50 Cent Rapper Life Review Essay Sample

50 Cent Rapper Life Review Essay Sample 50 Cent Rapper Life Review Essay Example 50 Cent Rapper Life Review Essay Example Inspiration, difficult work, good karma, and eagerness are the promise of achievement. In spite of the way that most of individuals partner accomplishment with cash, it is straightforwardly associated with the sentiment of fulfillment. Achievement includes a few basic parts of satisfaction, particularly physical and otherworldly wellbeing, passionate and, at last, material prosperity. Considering the way that various vocalists, artists, and rappers are named effective individuals, the given paper plans to reveal insight into the splendid vocation and fortune of 50 Cent in the circle of music and business. Life and Rap profession Thinking about the biographic information of 50 Cent, note that Curtis James Jackson III isn't just a perceived rapper yet a fruitful entertainer, financial specialist just as a business visionary (McKellop). In any case the way that 50 Cent confronted various issues in the past as the rapper took part in conveyance of medications during the â€Å"crack epidemic† during the 1980s, his â€Å"addiction† to music persuaded him to defeat himself and push ahead towards his fantasy. At present, 50 Cent is one of the most prosperous and, simultaneously, smash hit rappers on the planet. Curtis Jackson effectively endure disappointment while in transit to progress and increased overall acknowledgment (McKellop). For instance, in 1994, while sedate managing and ownership, he had to invest some energy in the restorative training camp. In any case, this severe educational experience didn't block him while in transit to overall acclaim. At the end of the day, troublesome adolescence , mother’s passing, and medication managing didn't destroy the determination of this popular man (McKellop). Rap vocation might be contrasted with an alleged direction point that persuaded 50 Cent not to surrender and battle as far as possible. At present, an expected total assets of 50 Cent is equivalent to $140 million (McKellop). Regardless of the way that numerous individuals guarantee that achievement and popularity of 50 Cent are practically unbelievable, Curtis Jackson’s story is unimaginably rousing. There are various persuading proofs that clarify the exceptional achievement of 50 Cent as an overall prestigious rapper just as an incredible business person (Hamm). In any case, it is somewhat imperative to take note of that 50 Cent always remembers about difficult work. As indicated by the perspective of 50 Cent, this standard is the most dependable on the grounds that diligent work will be compensated in a specific snapshot of people’s life. Furthermore, serious authenticity is viewed as the second key to progress. Robert Greene, the coauthor of the book The 50th Law communicates the possibility that 50 Cent has a one of a kind capacity to survey genuine circumstances in a fitting manner and make decisions about essentialness of these circumstances in the serious business world (Hamm). 50 Cent guarantees that individuals who need to prevail in future should concentrate on their encounters while beginning another business, since experience allows individuals to discover the exit from the most noticeably awful circumstances. Life, as 50 Cent accepts, is a game, thusly experience is certifiably not an exercise in futility, however a significant wellspring of information and the extraordinary chance to maintain a strategic distance from life traps and slip-ups. Thirdly, the rapper guarantees that fruitful individuals should occupy room on the planet. As such, extraordinary certainty, chance taking, and, at long last, brave conduct have impacted the accomplishment of 50 Cent (Hamm). 50 Cent is an interesting individual since he shrouds his feelings of dread, distrust, and uncertainty before enormous business magnates. Additionally, 50 Cent is an aggressive and fearless rapper that goes about as an innovator in the business world. At last, companions of 50 Cent admit that he is a staggeringly quiet individual who has prevailing with regards to defeating debilitation and disappointments (Hamm). During the meeting with 50 Cent about his phenomenal achievement, he guarantees that he followed various â€Å"rules† that helped him to push his fortunes. With in excess of 30 million collections sold during his splendid vocation, this well known man has energized a large number of individuals around the world not to surrender in spite of various challenges. Considering the perspective of Evan Carmichael, 50 Cent is an exceptional individual who began from the base and with the course of time rose to the highest point of progress, popularity, riches, and fortune. In this manner, the most huge standards that allowed the rapper to outperform himself are as per the following (Hamm): difficult work; eagerness; thought and appraisal of past additions and mix-ups; understanding that cash isn't the main estimation of achievement; seeking after own fantasies; being prepared to acknowledge the hazard; having great comical inclination; being prepared to give back (Hamm). As indicated by the estimations of 50 Cent, he as a rapper has figured out how to make his rap vocation, and, thus, melodic achievement since he never surrenders. In one of his ongoing meetings, 50 Cents gives certain proposals or â€Å"tips† to individuals who are eager to make progress in their life (Western). As a matter of first importance, 50 Cent asserts that the main voice that truly matters is yours. As such, the rapper guarantees that mistrust and questions keep individuals from pushing ahead. Besides, 50 Cent admits that he has consistently attempted to rethink himself since this extraordinary component gives him the magnificent opportunity to adjust to changing states of the business condition. In such a manner, supposed â€Å"reinvention† will offer an opportunity to each fan to be tuned-in and go with the occasions (Western). Thirdly, the rapper guarantees that effective individuals ought not bargain their character. In straightforward words, the rapper gua rantees that on the off chance that family, companions, and family members state that one’s dreams are ridiculous, individuals ought to disregard them since they will neglect to arrive at their fantasies with such â€Å"reliable† support (Western). Fourthly, the rapper expresses that he has consistently continued working. 50 Cent accepts that things will consistently turn out badly on the off chance that lethargy surpasses endeavors and work. Ingenuity, trust in close to home qualities, and energy will allow individuals to accomplish significance. Fifthly, 50 Cent admits that he has given as long as he can remember to his fantasies (Western). For example, the expression â€Å"get rich or kick the bucket trying† is viewed as the existence philosophy of 50 Cent. In addition, it is critical to take note of the way this recognized rapper expresses the passing ought to spur individuals as opposed to devastating them. For example, during one of the meetings, 50 Cent s ays that when he almost kicked the bucket, it made him imagine that it could happen again any second (Western). Subsequently, he settled on a choice to live like he had never lived. At the end of the day, nothing should stop individuals on their approach to progress. Thus, individuals ought not be exhausted and do nothing in light of the fact that the hour of each individual is constrained. In this manner, 50 Cent asserts that individuals who long for cash, achievement, and satisfaction should gain ground towards their internal objectives, travel, get new encounters, and meet new individuals (Western). The acclaimed rapper confirms that he has figured out how to battle fatigue and lethargy. He guarantees that numerous individuals in this world are despondent in light of the fact that they neglect to adapt to fatigue (Western). At last, 50 Cent, probably the wealthiest superstar in the realm of music, is persuaded that each negative experience is really a positive one since disappointment shares nothing for all intents and purpose with an all out misfortune. Despite what might be expected, disappointment ought to be comprehended as an unavoidable component or part of the achievement that radically builds the odds of individuals to do things the correct way (Western). Having decided, investigated, and surveyed triumphs and fortunes of 50 Cent in the circle of music and business, I might want to pressure that the life story of 50 Cent has truly enlivened me. In spite of the way that I am not an expert who can pass judgment on such a notable character as 50 Cent, and reprimand his victories just as disappointments in music and money related circles, I accept that 50 Cent is a â€Å"created person†. At the end of the day, I am an advocate of the possibility that heritability and qualities share nothing for all intents and purpose with his huge achievement and worldwide acknowledgment. Actually, I am persuaded that he â€Å"created† himself, his popularity, and riches with the assistance of his craving, eagerness, difficult character, and all around created administration attributes. To be completely forthright, I believe that 50 Cent doesn't set limitations and impediments on what he can accomplish. Thus, he has prevailing with regards to turning into a well off business visionary, entertainer, vocalist, and rapper since he never puts confines on himself and his qualities. He is an independent and sure individual who has gotten his own chief. At last, I might want to summarize that I very value his promise to his work, commitment with his fans or supporters, and, at long last his charity. Regardless of his money related issues and various defects, I accept that 50 Cent is perhaps the most brilliant case of eminent superstars who made careful arrangements so as to pick up staggeringly gigantic melodic and business victories. To be completely forthright, on the off chance that I had a chance, I would do nothing another way on the phase of hip jump and account since I totally consent to the choices of 50 Cent. At the end of the day, I accept that tremendous accomplishment of this rapper in the circles of business and music might be clarified by the correct choices he made. Conseque ntly, as I would see it, he was not mixed up when he chose to consolidate rapper profession with business, ventures, and, at long last, charity. I guess that such suggestions of 50 Cent as finding tremendous open doors even in disappointments, keeping the stream moving, regarding process just as understanding, dismissing the cutoff points, and, at long last, standing up to the mortality might be foll

Reflection writing assignment Essay Example | Topics and Well Written Essays - 250 words

Reflection composing task - Essay Example It originates from inside us. We focus on arranging and thinking how to change our intricate contemplations into a sorted out composed content. Now and then, I would end up gazing at a clear paper for a considerable length of time since I don't have the foggiest idea how to begin the subject I am working. More awful, when I get the chance to begin composing, I would it hard to end the subject. Additionally, I would once in a while be befuddled in linguistic guidelines particularly when I develop complex sentences. In addition, I need direction in utilizing the correct accentuations for longer sentences. Be that as it may, in the midst of every one of these troubles I experienced recorded as a hard copy, I have stayed persistent in re-composing and altering my drafts to think of a satisfactory paper. Composing a diagram likewise causes me in sorting out my contemplations and thoughts. The vast majority of all, I attempt to peruse a great deal so as to gain more from the distinctive composing styles of creators. I accept that training is the main way that I could ace the

Water, Plants, Humanity and the Future

Water, Plants, Humanity and the Future “A company’s  journey, led by two recent college graduates, to use plants to solve the global water crisis by following key 5-steps” © Shutterstock.com | Riccardo MayerIn this article, the founders of Everwaters share their insights on (1) how market research helped them define the customer problem they want to solve and (2) how they brainstormed and validated their solution ideas.The entrepreneur: passionate, unrelenting, courageous, and, arguably, insensible at times when it comes to believing in their ideas and visions a friend of mine likes to think “entrepreneurs all have a weird tick,” something that bothers them so much that they start a company to solve it. My Co-Founder,  Matthew Lisle, and I definitely have a  tick: 3.4 million people, mostly children under the age of five, across the world die each year because of contaminated drinking water; it kills more than malaria, measles, and AIDS combined per day.If you look at history of the United States, a doctor, John Leal, in 1908 decided one day to pour chlorine, without the approval of local authorities, in Jersey City’s municipal water supply. Wi th over 200,000 people depending on it, a mistake would cost thousands of lives; fortunately, this tick to clean contaminated water proved a success. Dr. Leal revolutionized water treatment in the United States and, almost immediately, he decreased infant mortality by  74%  and total mortality by  43%  that means 7 out of 10 children under the age of five were now being saved practically overnight.There is a reason water is deemed the “elixir of life”, but we have another problem: it’s 2016 and 783 million people still lack access to clean, affordable drinking water, a problem we solved in 1908! I ask myself everyday: “If we’ve solved this problem at home, why does it still exist, and arguably, worsen with time, abroad?” Our company,  Everwaters, has a tick, or belief, that we can solve this global crisis.Enter Moringa oleifera  (MO), colloquially known as the “Miracle Tree.” This tree cleans water yes, a plant can turn dirty water into safe, drinkable water (Fig. 1 2): Figures 1 2People in the Sudan have long used the seeds of the Moringa tree (Fig. 3) to coat their vessels to clean water and, for over twenty years, researchers in many countries have explored the water purification abilities of Moringa seeds (Fig. 4). Our company is taking this research out of the lab, integrating with a novel business model, and pioneering plant-based water treatment technology to provide “clean drinking water, for everyone, for life.” Figures 3 4Think of us as the Brita of the underdeveloped world.  Everwaters  creates a plant-based, household water filter that removes microbes responsible for water related illnesses, such as cholera, typhoid, etc. these are the microbes that are responsible for 3.4 million deaths per year, but fortunately, our “Miracle” is here.So, what? We have plants that clean water, do we travel around the world and tell everyone to grow it? How do we achieve widespread adoption to combat this global crisis? Through this article, I’ll explain our company’s  journey, all the  challenges  we faced, and future  vision  of where we see plants and water creating a healthier world for all. Through our story, we’ll provide aspiring entrepreneurs with a simple  5-step process  to identify a market-problem and develop a suitable business plan to solve it. Figure 5For starters, is there to a better way to understand a problem than jumping headfirst? After all, it’s all about the journey. As two aspiring entrepreneurs eager to understand the water crisis, we began our adventure by booking a flight to Kenya (Fig. 5).Step 1: Defining the Problem  Real Market ResearchDuring our two month stay in Kenya, in addition to the occasional elephant crossing the road and zebra grazing in the backyard, we had one goal in mind: “define the problem; speak to as many people about their water problem.” During the occasional candle-lit dinner power went out on Thursdays we all sat around, drank tea, and had a real heart-to-heart: many mothers, like our friend Mamamwangi, walk for hours every day to fill an empty jug from the local well (Fig. 6). If walking is too strenuous, many gather water from a local trench (Fig. 7), which is shared by local cattle and goats.The containers are unclean and heavy, and when it rains many prefer to collect and s tore rainwater at home. By storing them, however, in open containers at home, the water gets infected and provides prime real estate for mosquitos to breed. To make matters more difficult, most families earn about $60/month; they spend about $40 on school fees, and the remaining $20 is used sustain their homes and put food on the table. Given that competing solutions cost between $25-$40, some even $90, the problem is clear. Figures 6 7Step 2: Research How are people currently trying to solve the problem? How can successful solutions in other industries complement our company’s goal?Existing solutions are impractical for most families to purchase, and after further interviewing, this is the main reason why many prefer to stick with rainwater or water from the local trench and spring.The World Health Organization, USAID, and the United Nations agree that a simple, affordable, point-of-use household filter has the highest potential of acceptance and prolonged usage in the underdeveloped world. By combining an in-depth understanding of the problem with further industry research and recommendations, we came to the conclusion that our plant-based “Brita of the developing world” at the right price, may best be suited to solve this problem.After we developed the most basic version of our product, or minimum viable product (MVP)    we designed a CAD model we went around asking our friends in both urban and rural communities for their opinions (Fig. 8 9). Figures 8 9This was critical during the development of our MVP. By obtaining their feedback on the initial design, we were able to modify certain elements of it to better suit our future customer’s needs. Companies exist to solve problems for a specific segment of people who deem it valuable to be solved, and in this context of urban and rural communities in Kenya, the same principle applies. Obtaining appropriate user feedback on an MVP was quite difficult: communities were 40 minutes away by car on a dirt road, language barriers made it difficult to ask the “right question” and cultural norms were absolute musts in order to gain our customer’s trust.At any company, trust between your customers needs to be established to obtain high-quality information about the problem and feedback about a potential solution. In order to gain trust, we visited their homes, invited our friends to lunch and dinner, and shared stories over the famous Kenyan beer, Tusker. During our conversati ons, we learned about other successful companies: M-PESA, a mobile banking platform used by over 72% of the population, M-KOPA, a pay-as-you-use solar company, and thought about ways to incorporate their successful programs with our product.Step 3: Brainstorm  Every idea, good or bad, counts. Figure 10Once we understood the problem and its context in the urban and rural communities, we had a brainstorming session: late night food runs, work-induced mania, the occasional office chair push ups, and 4:30 a.m. conversations about integrating a plant-based filter into a sustainable business model; we rolled up our sleeves and wrote down every crazy idea that came to mind on the office white board (Fig. 10).Our unfettered brainstorming session created a slew of ideas, some more applicable than others:Use social entrepreneurship tools this specific breed of entrepreneur has not one, but two ticks: profits and social impactUse the mobile banking platform, M-PESA, which over 72% of the population usesSell crushed moringa seedsHoverboards should be part of company cultureAsk the government to grow moringaMarket to a specific segmentRemember Peter Drucker’s wisdom: “If it’s not measured, it’s not managed”Local service centers selling filtersAbandon ship?By setting the exp ectation that no idea is crazy enough, we produced a novel approach to integrating our filter in the local community: set-up users through a flexible payment plan via M-PESA, a mobile banking platform, and distribute through local service centers.Bingo!Step 4: Prototype Iterate, Iterate, and create a solution to the problem, not a problem for the solution.Once we had a comprehensive list of ideas to pursue, we made it a point to, in the least amount of time as possible, rule out or pursue suggestions some call this being “lean”. To accomplish this, we drafted more lists of questions and surveys and took them directly to our potential customers. Customers are great at explaining their problems, but it is up to the entrepreneur to develop the solution if Henry Ford asked his customers for a solution, they would say faster horses.A great product sells itself, and through steps 1,2, and 3, we were able to iterate on ideas for a solution to a well-defined problem, market-segment, all within the context of competing solutions and business models. Many household filters we saw were solutions designed without the end-user in mind, creating an unpopular product that has never penetrated this underserved market segment across the world. Figure 11We knew what we wanted to make; we spent countless hours walking through local cities to find the supplies to make our MVP: PVC piping, moringa seeds, and some basic hardware. After some time, and bartering, we had the materials and developed a prototype for further testing (Fig. 11).Our tests were negative, suggesting our technique was not working as well as we thought. The filtered water was unclean and we knew we needed to think different. Dozens of tests were carried out, and it was at this point where a keen quote kept our spirits up:“Would you like me to give you a formula for success? It’s quite simple, really. Double your rate of failure.” Thomas Watson, Founder of IBM.Imagine this scenario and all the possibilities for things to go wrong: within 6 hours, including a 4-hour drive on a one-lane road from Loitokitok, a city southeast of Nairobi, Kenya, we had to stop at three different natural springs and collect three water samples. After driving for 4 hours, w e passed off the water samples to a local motorcycle driver and prayed the samples were delivered in time; it was late, and all of our tests were invalid.We tried, and tried, quickly discarding hypotheses and identifying ways to correct our previous mistakes. Many of my entrepreneurial friends call this scenario the major slump of the company’s lifespan: you either push threw it, aka pivot, or perish. Because of the failed experiments and difficulties with logistics in Kenya, we decided to cut our trip early and fly back to the United States to recreate our experiments this was a tough and expensive decision: we were bootstrapping, but we took a leap a faith and decided it was necessary.During this iteration phase, teams need to establish hard, fast deadlines. With goals and milestones in the short and long term, and ways to track the progression of them, startup companies begin to foster a culture of execution, accountability, and can then adjust to better position future delive rables on a timely schedule. Our team struggled at first, but by agreeing on deliverables and deadlines, we were able to prioritize our tasks and quickly iterate on experiments, filter designs, and business models.With deadlines, well-defined deliverables, and water testing at a nearby facility in Philadelphia, we showed significant and achieved much more promising results (Fig. 12 13): Figures 12 13Wherever we were, with whatever resources we had, both product supplies and customers to interview, we made the most out of them by moving quickly to confirm or reject different hypotheses that we brainstormed in step 3.Always think:“What is the most important question I need to answer, and how can I do it with the least about of time and money.” Step 5: Think Big  picture the company 5, 10, 20 years down the road.Our technology, business plan, and overall goal is to pioneer plant-based water treatment technology. In the long term, we see many uses for this technology: on an industrial scale, researchers claim that the technique, which we are refining, will produce fewer and more useful by-products and eliminate chemical traces that have raised public health concerns in municipal water supplies. By thinking 5, 10, 20 years down the road, we strengthen our message, identify short-term and long-term company goals, and provide a meaningful future that attracts money, talent, and other resources to fuel our efforts.Take a page out of Peter Thiel’s “Zero to One,” and create the future: create a world, where if your company didn’t exist, we would all lose something very special.Here is our example: Our goal is to address the United Nation’s Sustainable Development Goals, which calls to end poverty, fight inequality and injustice, and tackle climate change by 2030. To accomplish these goals, we must address a fundamental issue: access to clean, affordable drinking water. Without clean water, children miss school, families are burdened by medical bills and high infant mortality rates, cascading to stifle economic prosperity and trapping billions in poverty and disease. At Everwaters, we believe water is life, and through social entrepreneurship, or market-based thinking and entrepreneurial capitalism in a social context, we will work to provide “clean water, for everyone, for life.”So the next time you have a tick, think back to our sto ry and how, regardless where you are in the world or what problem you are trying to solve, there are 5-steps to solve problems and get your idea off-the-ground: Define, Research, Brainstorm, Prototype, and Think Big. Our team is working hard to innovate and solve the global water crisis because we believe no one should die from drinking dirty water. We believe that every child should have the same chance to thrive and live a fulfilling life. Follow us on social media as we continue to develop our technology and distribute a plant-based household water filtration system to the whole world.What problem will you solve? What idea do you have to change the world? What’s the hardest part about turning your great idea into reality?____________________________Check out our crowdfunding campaign on  Indiegogo, ‘Water, Plants, Humanity and the Future’ in partnership with the  Millennial Train Project.” This 10-day trip will take us across the country, spreading the idea to use plants to clean water and save millions of lives across the world.Currently Located in Philadelphia, PA,  Everwaters  is developing plant-based household water filters in Kenya with plans to expand to Tanzania, Uganda, East Africa, Latin America, India, and the United States. Since its Founding in June 2015,  Everwaters  has been developing a plant-based filtration technique and has been recognized for its pioneering business model and technology, notably winning the 2015 Inaugural 2015  UPenn’s President’s Engagement Prize.  Co-Founders,  Adrian Lievano, CEO, and  Matthew Lisle, CTO, are two recent Mechanical Engineering graduates from the University of Pennsylvania working to combat the world water crisis, with plants.   All figures (1-13) are designed and photographed by the team of Everwaters in the year of 2015; the author is Everwaters, LLC. Copyrighted some rights reserved.

Back-to-School Student Questionnaire

One of the challenges of starting a new school year is getting acquainted with your students. Some students are friendly and talkative right away, while others may be shy or reserved. Provide students with a back-to-school questionnaire to learn more about each student in your class. You can also combine student questionnaires with other icebreakers during the first week of school. Sample Student Questions The following questions are some examples to consider including in your own questionnaire. Modify the questions to suit your students grade level. If you need a second opinion, run your questionnaire draft by an administrator or a fellow teacher. You dont need to have students answer every question, though you might want to give them an incentive to participate. And remember, students want to get to know you better, too—so fill out a questionnaire of your own and distribute it. Personal Details What is your full name?Do you like your name? Why or why not?Do you have a nickname? If so, what is it?When is your birthday?Do you have any siblings? If so, how many?Do you have any pets? If so, tell me about them.Who is your favorite relative? Why? Future Goals What career do you hope to have?Do you want to go to college? Why or why not?If you want to go to college, which one do you want to attend?Where do you see yourself in five years? Ten years?Do you plan to stay in this area or move away? Specific Information About This Class What do you think about [the grade level and/or subject matter you teach]?What concerns, if any, do you have about this class?What do you hope to learn in this class?What grade are you striving to earn in this class? This Year in School What are you most looking forward to this year?What are you least looking forward to this year?Which school clubs are you planning to participate in this year?What extracurricular activities do you plan to join this year—such as sports, theater, or band?Do you think that you learn better by seeing, hearing, or doing something?Do you consider yourself well organized?Where do you typically do your homework?Do you like to listen to music while you do schoolwork? Free Time Who are your friends in this class?What do you like to do in your free time?What are your hobbies?Whats your favorite type of music?Whats your favorite TV show?Whats your favorite type of movie? (For example, you might choose thrillers, romantic comedies, or horror movies.) Why do you like that genre? More About You Whats your favorite color?If you could invite three famous people to dinner, who would they be and why?What do you think is the most important quality that a teacher can have?Five adjectives that describe me are:If you were given a first-class ticket to travel anywhere in the world, where would you go and why?

I Am Close With Damon - 971 Words

Since the age of fifteen, I have been dating my boyfriend, Damon, whose family has accepted me as their own. Last year, Damon’s step-brother Elijah had a wonderful little girl named Korra. She is now 11 months old and beginning to exhibit signs of development that we have been exploring in our class work. Since I am close with Damon’s family, I have been able to see at least once a week and watch her develop and learn new things, allowing me to compare her to one of our recent chapters, which was development. I have noticed that Korra is showing Secure Attachment when with her mother, Jessica. When Korra is with her, she is a very happy baby who is willing to be around others that she recognizes and is not afraid to play with her toys; but when her mother leaves she begins to panic and cry out for Jessica to come back. This weekend we had a party for Damon’s youngest sister, and she had many friends over to play and celebrate. When Jessica left Korra with Damonâ €™s sister and her friends, Korra became scared and began to cry for her mother; and when mom returned, Korra was happy and no longer crying. The text book refers to secure attachment as â€Å"in their mother’s presence they play comfortably, happily exploring their new environment† (Meyers Dewall, 2014). Korra is a direct reflection of this statement of the book, depicting that she has a healthy relationship with her mother. The Stranger Anxiety Korra exhibits when her mother leaves is very typical for aShow MoreRelatedViolence In Films Essay720 Words   |  3 PagesViolence In Films In this essay I am going to compare 3 scenes of violence from 3 different genres and analyse their certifications and effects on young people and whether children are finding ways of viewing secretly, or are being allowed to see, too much violence in films, T.V or through any other median. 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Hydraulic Design of Small Hydro Plants Free Essays

Version 2 STANDARDS/MANUALS/ GUIDELINES FOR SMALL HYDRO DEVELOPMENT Civil Works – Hydraulic Design Of Small Hydro Plants Lead Organization: Sponsor: Alternate Hydro Energy Center Indian Institute of Technology Roorkee Ministry of New and Renewable Energy Govt. of India May 2011 AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  1 1. GUIDELINES FOR HYDRAULIC DESIGN OF SMALL HYDRO PLANTS This section provides standards and guidelines on the design of the water conductor system. We will write a custom essay sample on Hydraulic Design of Small Hydro Plants or any similar topic only for you Order Now This system includes; head works and intake, feeder canal, desilter (if required), power canal or alternative conveyance structures (culverts, pipelines, tunnels, etc), forebay tank, penstock and surge tank (if required) up to the entry of the turbine, tailrace canal below the turbine and related ancillary works. 1. 1 HYDRAULIC DESIGN OF HEAD WORKS In general head works are composed of three structural components, diversion dam, intake and bed load sluice. The functions of the head works are: Diversion of the required project flow from the river into the water conductor system. Control of sediment. Flood handling. Typically a head pond reservoir is formed upstream of the head works. This reservoir may be used to provide daily pondage in support of peaking operation or to provide the control volume necessary for turbine operation in the water level control mode. This latter case would apply where the penstock draws its water directly from the head pond. Sufficient volume must be provided to support these functions. There are three types of head works that are widely used on mini and small hydro projects, as below: Lateral intake head works Trench intake head works Reservoir / canal intakes Each type will be discussed in turn. 1. 1. 1 Head Works with Lateral Intakes (Small Hydro) Head works with lateral intakes are typically applied on rivers transporting significant amounts of sediment as bed load and in suspension. The functional objectives are: To divert bed-load away from the intake and flush downstream of the dam (the bed load flushing system should be operable in both continuous and intermittent modes). To decant relatively clean surface water into the intake. To arrest floating debris at intake trashracks for removal by manual raking. To safely discharge the design flood without causing unacceptable upstream flooding. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  2 The following site features promote favourable hydraulic conditions and should be considered during site selection: The intake should be located on the outside of a river bend (towards the end of the bend) to benefit from the spiral current in the river that moves clean surface water towards the intake and bed load away from the intake towards the centre of the river. The intake should be located at the head of a steeper section of the river. This will promote removal of material flushed through the dam which may otherwise accumulate downstream of the flushing channel and impair its function. Satisfactory foundation conditions. Ideal site conditions are rare, thus design will require compromises between hydraulic requirements and constraints of site geology, accessibility etc. The following guidelines assume head works are located on a straight reach of a river. For important projects or unusual sites hydraulic model studies are recommended. A step by step design approach is recommended and design parameters are suggested for guidance in design and layout studies. Typical layouts are shown in Figures 2. 2. 1 to 2. 2. 3. 1. 1. 2 Data Required for design. The following data are required for design: Site hydrology report as stipulated in Section 1. 3 of this Standard giving: – Qp (plant flow) – Q100 (design flood flow, small hydro) – Q10 (design flood flow, mini hydro) (data on suspended sediment loads) – Cw – H-Q Curves (W. L. rating curves at diversion dam) Topographic mapping of the site including river bathymetry covering all head works structure sites. Site geology report. 1. 1. 3 Site Selection: Selection of the head works site is a practical decision which involves weighing of several factors including hydraulic desiderata (Section 2. 2. 1/1. 0), head optimization, foundation conditions, accessibility and constructability factors. Given the importance of intake design to the overall performance of the plant it is recommended that an experienced hydraulic engineer be consulted during studies on head works layout. 1. 1. 4 Determination of Key Elevations: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  3 For the illustrative example: Qp = 10. 0 m3/s Determine V0 = 0. 5 Q0. 2 (= 0. 792, say 0. 80 m/s) (= 12. 5 m2) A0 = Q ? V0 A0 H= (= 1. 77 m, say 1. 80 m) 4 Assume L = 4H (= 7. 08 m, say 7. 0 m) ye = greater of 0. 5 yo or 1. 5 m (= 1. 80m) yd = L. S (= 0. 28 m) NOL = Z0 + ye + yd + H NOL = 97. 5 + 1. 80 + 0. 28 + 1. 80 (=101. 38m, say 101. 50 m) Sill = NOL – H (= 99. 7m) Crest of weir or head pond NOL = 101. 5 m Height of weir = 4. 0 m These initial key elevations are preliminary and may have to be adjusted later as the design evolves. 1. 1. 5 Head Works Layout The entry to the intake should be aligned with the river bank to provide smooth approach conditions and minimize the occurrence of undesirable swirl. A guide wall acting as a transition between the river bank and the structure will usually be required. Intake hydraulics are enhanced if the intake face is slightly tilted into the flow. The orientation of the intake face depends on river bank topography, for straight river reaches the recommended values for tilt vary from 10o to 30o depending on the author. When this angle becomes too large the intake will attract excessive amounts of sediment and floating debris. It is recommended that the sill level of the intake is kept sufficiently higher than the sill level of the under sluice. The under sluice should be located adjacent to the intake structure. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  4 For development of the head work plan, it is recommended that the following parameters be used for layout: Axis of intake should between 100 ° to 105 ° to axis of diversion structure The actual inclination may be finalized on the basis of model studies. Divide wall, if provided, should cover 80% to 100% of the intake. Assume flushing flow equal to twice project flow then estimate the width and height of the flushing gate from orifice formula,: Example should be in appendix. Qf = 0. 6 ? 0. 5W2 Where: Qf = flushing flow W = gate width H = gate height (= 0. 5W) Yo = normal flow depth as shown in 2. 2. 1. 1/2. 0 Sill should be straight and perpendicular to the flow direction. In the sample design (Fig. 2. 2. 1. 1) the axis of the intake = 105 ° Qf = 2. 0? 10. 0 = 20m3/s ? 20. 0 = 0. 6 ? 0. 5 W2 ? W = 2. 8 m (say 3. 0m) and H = 1. 5 m. 1. 1. 6 Flood Handling, MFL and Number of Gates. For small hydro a simple overflow diversion weir would be the preferred option if flood surcharge would not cause unacceptable upstream flooding. For purpose of illustration, the following design data are assumed (see Figure 2. 2. 2): Design flood, Q100 = 175 m3/s A review of reservoir topography indicated that over bank flooding would occur if the flood water level exceeded 103. 0 m. Select this water level as the MFL. This provides a flood surcharge (S) of 1. 20 m. Assume weir coefficients as below: Gate, Cw = 1. 70 – – – sill on slab at river bottom. Weir, Cw = 1. 0 – – – – – – -ogee profile. Assume gate W/H ratio = 1:2 H = 4. 0 m ? W = 4. 8 (say 5. 0 m) MFL. = NOL + 1. 50 (= 103. 0m) Qgate = Cw. W. (MFL – ZS)1.. 5 Qweir = Cw. Lw. S1. 5 Capacity check for MFL = 103. 0 m No. of Length of Overflow QG Gates Section (m) (m3/s) 0 35. 0 0. 0 1 29. 0 109. 6 QW (m3/s) 82. 8 68. 6 QT (m3/s) 82. 8 178. 2 175 AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  5 Therefore one gate is sufficient. Where: MFL = Maximum flood level (m) NOL = Normal operating level (m) S = flood surcharge above NOL (m) W = width of gate (m) H = height of gate (m) ZS = elevation of gate sill (m) = weir coefficient (m0. 5s-1) Cw QG, QW, QT = gate, weir and total flows The flow capacity of the sediment flushing gate may also be included in calculating flood handling capacity. 1. 1. 7 Diversion structure and Spillway Plains Rivers: Stability of structures founded on alluvial foundations typical of plains rivers, is governed by the magnitude of the exit gradient. The critical gradient is approximately 1. 0 and shall be reduced by the following safety factors: Types of foundation Shingles / cobbles Coarse sand Fine sand Safety factor 5 6 7 Allowable Exit Gradient 0. 20 0. 167 0. 143 Also diversion structures on plains rivers will normally require stilling basins to dissipate the energy from the fall across the diversion structure before the water can be returned safely to the river. Design of diversion weirs and barrages on permeable foundation should follow IS 6966 (Part 1). Sample calculations in Chapter 12 of â€Å"Fundamentals of Irrigation Engineering† (Bharat Singh, 1983) explain determination of uplift pressure distributions and exit gradients. Further details on structural aspects of design are given in Section 2. 3. 3 of this Standard. Mountain Rivers: Bedrock is usually found at relatively shallow depths in mountain rivers permitting head works structures to be founded on rock. Also the beds of mountain rivers are often boulder paved and are much more resistant to erosion than plains rivers. Therefore there may be no need for a stilling basin. The engineer may consider impact blocks on the downstream apron or simply provide an angled lip at the downstream end of the apron to â€Å"flip† the flow away from the downstream end of the apron. A cut-off wall to bed rock of suitable depth should AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  6 also be provided for added protection against undermining by scour. The head works structures would be designed as gravity structures with enough mass to resist flotation. For low structures height less than 2. 0 m anchors into sound bedrock may be used as the prime stabilization element in dam design. Stability and stress design shall be in accordance with requirements of Section 2. 3. 3 of this Standard. 1. 1. 8 Sediment Flushing Channel To be reviewed The following approach is recommended for design of the flushing channel: Select flushing channel flow capacity (Qf) = 2? Qp Estimate maximum size of sediment entering the pocket from site data or from transport capacity of approaching flow and velocity. In case of diversion weir without gates assume sediment accumulation to be level with the weir crest. (Assume continuous flushing with 3? Qp entering the pocket, for this calculation). Establish entrance sill elevation and channel slope assuming an intermittent flushing mode (intake closed) with Qs = 2Qp, critical flow at the sill, supercritical flow downstream (FN ? 1. 0) and a reservoir operating level 0. 5m below NOL. Determine slope of channel to provide the required scouring velocity, using the following formula which incorporates a safety factor of 1. 5: i = 1. 50 io d 9/7 i0 = 0. 44 6 / 7 q Where: io = critical scouring velocity d = sediment size q = flow per unit width (m3/s per m) Verify that flow through pocket in continuou s flushing mode (Qs = 3Qs) will be sub critical, if not lower entrance sill elevation further. Determine height of gate and gate opening based on depth of flow at gate location and corresponding gate width. Increase the above theoretical gate height by 0. 5 m to ensure unrestricted open channel flow through the gate for intermittent flushing mode and a flushing flow of 2 Qp. For initial design a width to height ratio of 2:1 for the flushing gate is suggested. 1. 1. 9 Intake/Head Regulator: In intake provides a transition between the river and the feeder canal. The main design objectives are to exclude bed-load and floating debris and to minimize head losses. The following parameters are recommended: Approach velocity at intake entrance (on gross area) 0. 20 Ve = 0. 5 Q p m / s For trashracks that are manually cleaned, V should not exceed 1. 0 m/s. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  7 Convergence of side walls 2. 5:1 with rate of increase in velocity not exceeding 0. 5 m/s per linear m. †¢ Height of sill above floor of flushing channel (ye) = greater of 1. 5m or 50% flow depth. †¢ The floor of the transition should be sloped down as required to join the invert of the feeder canal. Check that the flow velocity in the transition is adequate to prevent deposition in the transition area. If sediment loads are very high consider installing a vortex silt ejector at the downstream end of the transition. Provide coarse trashracks to guard entry to the head gate. The trashrack would be designed to step floating debris such as trees, branches, wood on other floating objects. A clear spacing of 150 mm between bars is recommended. Trashrack detailed design should be in accordance with IS 11388. †¢ The invert of the feeder canal shall be determi ned taking into consideration head losses through the trashrack and form losses through the structure. Friction losses can be omitted as they are negligible: V2 Calculate form losses as: H L = 0. 3 2 2g Where: V2 = velocity at downstream end of contraction. Calculate trashrack losses as: 4/3 V2 ?t? H L = K f ? ? . Sin? . 2g ?b? Where: Kf = head loss factor (= 2. 42 assuming rectangular bars) T = thickness of bars (mm) B = clear bar spacing (mm) ? = angle of inclination to horizontal (degrees) V = approach velocity (m/s) 1. 1. 10 References on Lateral Intakes and Diversion Weirs. IS Standards Cited: IS 6966 (Part 1) IS 11388 USBR (1987) Singh, Bharat Nigam, P. S. Hydraulic Design of Barrages and Weirs – Guidelines Recommendations for Design of Trashracks for Intakes Design of Small Dams Fundamentals of Irrigation Engineering Nem Chand Bros. Roorkee (1983) Handbook of Hydroelectric Engineering (Second edition) †¦.. pages 357 to 365 Nem Chand Bros. – Roorkee (1985) 1. 1. 11 Other References: Bucher and Krumdieck Guidelines for the Design of Intake Structures for Small Hydro Schemes; Hydro ’88/3rd International Conference on Small Hydro, Cancun – Mexico. Bouvard, M. Mobile Barrages and Intakes on Sediment Transporting AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  8 Razvan, E. 1. 2. Rivers; IAHR Monograph, A. A. Balkema – Rotterdam (1992) River Intakes and Diversion Dams Elsevier, Amsterdam (1988) SEMI PERMANENT HEADWORKS (MINI HYDRO) For mini hydro projects the need to minimize capital cost of the head works is of prime importance. This issue poses the greatest challenge where the head works have to be constructed on alluvial foundations. This challenge is addressed by adoption of less rigorous standards and the application of simplified designs adapted to the skills available in remote areas. A typical layout is shown in Figure 2. 2. 3. 1. 2. 1 Design Parameters Hydraulic design should be based on the following design criteria: Plant flow Qp) = QT + QD Where: QT = total turbine flow (m3/s) QD = desilter flushing flow (= 0. 20 QT) m3/s QFC = feeder canal flow (= 1. 20 QT) m3/s QF = gravel flushing flow (= 2. 0 QP) Spillway design flow (SDF) = Q10 Where: Q10 = flood peak flow with ten year return period. 1. 2. 2 Layout ? To be reviewed Intake approach velocity = 1. 0 m/s Regulator gate W/H = 2 Flushing channel depth (HD) = 2H + W/3 Flushing channel m inimum width = 1. 0 m Assumed flushing gate W/H = 2, determine H from orifice equation, as below: Q f = 0. 53? 2 H 2 . 2 gY1 Y1 = HD for design condition Where: W width of gate (m) H = height of gate (m) Yi = upstream depth (m) = depth of flushing channel (m) HD Select the next largest manufactures standard gate size above the calculated dimensions. 1. 2. 3 Weir AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  9 Determine weir height to suit intake gate and flushing gate dimensions, as shown in Figure 2. 2. 3. For weirs founded on permeable foundations the necessary structure length to control failure by piping should be determined in accordance with Section 2. 2. 1/4. 1 of this Standard. A stepped arrangement is recommended for the downstream face of the weir to dissipate hydraulic energy. The height of the steps should not exceed 0. 5 m and the rise over run ratio should not less than 1/3, the stability of the weir cross-section design should be checked for flotation, over turning and sliding in accordance with Section 2. 3. 1. 1. 3 TRENCH INTAKES Trench intakes are intake structures located in the river bed that draw off flow through racks into a trench which conveys the flow into the project water conductor system. A characteristic of trench intakes is that they have minimum impact on river levels. Trench intakes are applied in situations where traditional headwork designs would be excessively expensive or result in objectionable rises in river levels. There are two quite different applications: on wide rivers and on mountainous streams, but the basic equations are the same for both types. The trench intake should be located in the main river channel and be of sufficient width to collect the design project flow including all flushing flows. If the length of the trench is less than the width of the river, cut off walls will be required into each bank to prevent the river from bypassing the structure. Trench weirs function best on weirs with slopes greater than 4%-5%, for flatter slopes diversion weirs should be considered. The spacing between racks is selected to prevent entry of bed load into the trench. The following terms are sometimes used in referring to trench intake designs. Trench weir, when the trench is installed in a raised embankment. †¢ Tyrolean or Caucasian intakes, when referring to trench intakes on †¢ mountainous streams. Features: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  10 1. 3. 2 Design Parameters The following design parameters are suggested for the dimensioning of trench weirs. †¢ Design Flows: The following design flows are recommended: Bedload flushing flow (from collector box) = 0. 2 QT †¢ Desilter flushing flow = 0. 2 QT †¢ Turbine flow = 1. 0 QT †¢ Total design flow †¢ = 1. 4 QT Dimensional Layout AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  11 The following factors should be considered in determining the principal dimensions: length, breadth and depth of a trench weir: Minimum width (B)= 1. 25 m (to facilitate manual cleaning) Length should be compatible with river cross section. It is †¢ recommended that the trench be located across main river channel. Maximum width (B) ? 2. 50m. Trashrack bars longer than about 2. 50 m †¢ may require support as slenderness ratios become excessive. Invert of collector box should be kept a high as possible. †¢ †¢ Racks à ¢â‚¬ ¢ †¢ †¢ †¢ The clear spacing between bars should be selected to prevent entry of bed-load particles that are too large to be conveniently handled by the flushing system. Generally designs are based on excluding particles greater than medium gravel size from (2 cm to 4 cm). A clear opening of 3. 0 cm is recommended for design. A slope across the rack should be provided to avoid accumulation of bed load on the racks. Slopes normally used vary from 0 ° to 20 °. Rectangular bars are recommended. Bar structural dimension shall be designed in accordance with Section 2. 2. 1/5. 0 of this Standard. An appropriate contraction coefficient should be selected as explained in the following sub-section. Assume 30% blockage. Spacing between racks is designed to prevent the entry of bedload but must also be strong enough to support superimposed loads from bedload accumulation, men and equipment. This issue is discussed further in Subsection 2. 2. 3 / 2. 0. 1. 3. 3 Hydraulic Design of Trench Intake The first step in hydraulic design is to decide the width of the trench intake bearing in mind the flow capacity required and the bathymetry of the river bed. The next step in hydraulic design is to determine the minimum trench breadth (B) that will capture the required design flow. The design approach assumes complete capture of river flow, which implies, that river flow is equal to plant flow for the design condition. Hydraulic design is based on the following assumptions: Constant specific energy across racks. †¢ Effective head on screen is equal to base pressure (depth) †¢ Approach velocity is subcritical with a critical section at the entry to the structure as shown in figure 2. 2. 3/1. The set of equations proposed is based on the method given by Lauterjung et al (1989). †¢ First calculate y1: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraul ic Design Of Small Hydro Plants /May 2011  Ã‚  12 2 y 1 = k. H0 3 – – – – – – – – – – – (1) Where: y1 = depth at upstream edge of rack Ho = the energy head of the approaching flow k = an adjustment factor (m) m) (-) k is a function of inclination of the rack and can be determined from the following table: Values of k as a Function of Rack Slope (? ) Table: 2. 2. 1/1 ? = 0 ° 2 ° 4 ° 6 ° 8 ° 10 ° 12 ° k = 1. 000 0. 980 0. 961 0. 944 0. 927 0. 910 0. 894 ? = 14 ° 16 ° 18 ° 20 ° 22 ° 24 ° 26 ° k = 0. 879 0. 865 0. 851 0. 837 0. 852 0. 812 0. 800 Then calculate the breadth of the collector trench from the following equations (2) to (4) 1. 50 q – – – – – – – – – – – – – – (2) L= E1. E 2 C. cos? 3/2 . 2gy 1 Where: L = sloped length across collector trench (m) E1 = blockage factor E2 = Eff ective screen area = e/m C = contraction coefficient ? = slope of rack in degrees y1 = flow depth upstream from Equation 1. (m) q = unit flow entering intake (m3/s per m) e = clear distance between bars (cm or m) m = c/c spacing of bars (cm or m) Assume E1 = 0. 3 (30%) blockage. â€Å"C† can be calculated from the following formula (as reported by Raudkivi) Rectangular bars: ?e? C = 0. 66 ? ? ?m? ?0. 16 ?m? .? ? ?h? 0. 13 Assume h = 0. 5 y1. This formula is valid for 3. 5 – – – – – – – – – – – – – (3) h e 0. 2 and 0. 15 0. 30 m m Finally, the required breadth (B) can be determined as below: B = L cos ? – – – – – – – – – – – – -(4) AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  13 1. 3. 4 Hydraulic Design of Collector Trench Normally a sufficient slope on the i nvert of the trench is provided to ensure efficient flushing of bed-load particles that would otherwise accumulate on the invert of the trench. A suitable scouring slope can be estimated from the following equation: Ss = 0. 66 d 9 / 7 6/7 qo Where: d = sediment size (m) qo = flow per unit width (Q/B) at outlet of trench (m3/s per m) Ss = design slope of trench invert. The minimum depth of the trench at the upstream and is normally between 1. 0m to 1. 5 m, based on water depth plus a freeboard of 0. 3 m. For final design the flow profile should be computed for the design slope and the trench bottom profile confirmed or adjusted, as required. A step-by-step procedure for calculating the flow profile that is applicable to this problem can be found in Example 124, page 342-345 of â€Å"Open-Channel Hydraulics† by Ven. T. Chow (1959). In most cases the profile will be sub critical with control from the downstream (exit) end. A suitable starting point would be to assume critical flow depth at the exit of the trench. 1. 3. 5 Collector Chamber The trench terminates in a collector box. The collection box has two outlets, an intake to the water conductor system and a flushing pipe. The flushing pipe must be design with the capacity to flush the bed-load sediment entering from the trench, while the project flow is withdrawn via the intake. The bottom of the collection box must be designed to provide adequate submergence for the flushing pipe and intake to suppress undesirable vortices. The flushing pipe should be lower than the intake and the flushing pipe sized to handle the discharge of bed load. If the flushing pipe invert is below the outlet of the trench, the Engineer should consider steepening the trench invert. If the trench outlet invert is below the flushing pipe invert, the latter should be lowered to the elevation of the trench outlet or below. The deck of the collector box should be located above the design flood level to provide safe access to operate gates. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  14 1. 3. Flushing Pipe The flushing pipe should be designed to provide a high enough velocity to entrain bed-load captured by the weir. A velocity of at least 3. 0 m/s should be provided. If possible, the outlet end of the pipe should be located a minimum of 1. 0m above the river bed level to provide energy to keep the outlet area free from accumulation of bed load that could block t he pipeline. 1. 3. 7 References on Trench weirs CBIP, (2001): Manual on Planning and Design of Small Hydroelectric Scheme Lauterjung et al (1989): Planning of Intake Structures Freidrich Vieweg and Sohn, Braunswchweig – Germany IAHR (1993): Hydraulic Structures Design Manual: Sedimentation: Exclusion and Removal of Sediment from Diverted Water. By: Arved J. Raudkivi Publisher: Taylor Francis, New York. Chow (1959): Open- Channel Hydraulics Publisher: McGraw-Hill Book Company, New York. 1. 4 RESERVOIR, CANAL AND PENSTOCK INTAKES The designs of reservoir, canal and penstock intakes are all based on the same principles. However, there are significant variations depending on whether an intake is at the forebay reservoir of a run-of-river plant or at storage reservoir with large draw down or is for a power tunnel, etc. Examples of a variety of layouts can be fond in IS 9761 Hydropower Intakes – Criteria for Hydraulic Design or Guidelines for Design of Intakes for Hydropower Plants (ASCE, 1995). The features common to all designs are shown in the following sketch: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  15 The objectives of good design are: To prevent entry of floating debris. †¢ To avoid formation of air entraining vortices. †¢ To minimize hydraulic losses. †¢ 1. 4. 1 Control of floating debris To prevent the entry of debris a trashrack is placed at the entry to the intake. For small hydro plants the trashrack overall size is determined based on an approach velocity of 0. 75 m/s to 1. 0m/s to facilitate manual raking. Trashracks may be designed in panels that can be lowered into place in grooves provided in the intake walls or permanently attacked to anchors in the intake face. The trashracks should to sloped at 14 ° from the vertical (4V:1H) to facilitate raking. The spacing between bars is determined as a function of the spacing between turbine runner blades. IS 11388 Recommendations for Design of Trashracks for Intakes should be consulted for information about spacing between trashracks bars, structural design and vibration problems. Also, see Section 2. 2. 1/5 of this Standard. 1. 4. 2 Control of Vortices First of all the direction of approach velocity should be axial with respect the intake if at all possible. If flow approaches at a significant angle (greater than 45o) AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  16 from axial these will be significant risk of vortex problems. In such a situation an experienced hydraulic engineer should be consulted and for important projects hydraulic model studies may be required. For normal approach flow the submergence can be determined from the following formulae: S = 0. 725VD0. 5 S D V = submergence to the roof of the gate section (m) = diameter of penstock and height of gate (m) = velocity at gate for design flow. (m/s) Where: A recent paper by Raghavan and Ramachandran discusses the merits of various formulae for determining submergence (S). 1. 4. 3 Minimization of Head losses Head losses are minimized by providing a streamlined transition between the entry section and gate section. Minimum losses will be produced when a streamlined bellmouth intake is used. For a bellmouth intake the transition section is formed with quadrants of ellipses as shown in the following sketch. The bellmouth type intake is preferred when ever the additional costs are economically justified. For smaller, mainly mini hydropower stations, simpler designs are often optimal as the cost of construction of curved concrete surfaces may not be offset by the value of reduction in head losses. Details on the geometry of both types are given †¢ Bellmouth Intake Geometry Geometries for typical run-of-river intakes are shown below: A gate width to height of 0. 785 (D): 1. 00 (H) with H = D is recommended. This permits some reduction in the cost of gates without a significant sacrifice in hydraulic efficiency. There is a second transition between the gate and penstock, rectangular to circular. For a gate having H = D and W= 0. 785D the flow velocity at the gate will be equal to the velocity in the penstock so no further flow acceleration is produced in this section. A length for this transition of 1. x D should be satisfactory. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  17 The head loss co-efficient for this arrangement in Ki =0. 10 Details for layout of bell mouth transitions connecting to a sloping penstock are given in IS9761. †¢ Simplified layout (Mini-Hydro): For smaller/mini hydro project s intake design can be simplified by forming the transition in plane surfaces as shown below: The head loss for this design (Ki) = 0. 19V2/2g. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  18 . 4. 4. AIR VENT An air vent should be placed downstream of the head gate to facilitate air exchange between atmosphere and the penstock for the following conditions: †¢ Penstock filling when air will be expelled from the penstock as water enters. †¢ Penstock draining when air will enter the penstock to occupy the space previously filled by water. The air vent (pipe) must have an adequate cross section area to effectively handle these exchanges of air. The following design rules are recommended: Air vent area should the greater of the following values Where: (m3/s) AV = 0. 0 Ap or QT AV = 25. 0 (m2) AV = cross-section area of air vent pipe AP = cross-section area of penstock (m2) QP = turbine rated flow ( ? QT of m ore than one turbine on the penstock) The air vent should exhaust to a safe location unoccupied by power company employees on the general public. 1. 4. 5 PENSTOCK FILLING A penstock should be filled slowly to avoid excessive and dangerous â€Å"blowback†. The recommended practice is to control filling rate via the head gate. The AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  19 ead gate should not be opened more than 50 mm until the penstock is completely full. (This is sometime referred to as â€Å"cracking† the gate. ) 1. 4. 6 REFERENCES ON PENSTOCK INTAKES: †¢ 1. 4. 7 Indian Standard Cited. IS 9761: Hydropower Intakes – Criteria for Hydraulic Design OTHER REFERENCES †¢ Guidelines for Design of Intakes for Hydroelectric Plants ASCE, New York (1995) †¢ Validating the Design of an Intake Structure : By Narasimham Raghavan and M. K. Ramachandran, HRW – September 2007. â₠¬ ¢ Layman’s Guidebook European Small Hydro Association Brussels, Belgium (June 1998) Available on the internet. †¢ Vortices at Intakes By J. L. Gordon Water Power Dam Construction April 1970 1. 5. TRASHRACKS AND SAFETY RACKS 1. 5. 1 Trashracks: Trashracks at penstock intakes for small hydro plants should be sloped at 4 V: 1H to facilitate manual raking and the approach velocity to the trashracks limited to 1. 0 m/s or less. Use of rectangular bars is normal practice for SHP’s. Support beams should be alignment with the flow direction to minimize hydraulic losses. Detailed trashrack design should be done in accordance with IS 11388. 1. 5. 2 Safety Racks: Safety racks are required at tunnel and inverted siphon entries to prevent animals or people who may have fallen into the canal from being pulled into these submerged water ways. A clear spacing of 200 mm between bars is recommended. Other aspects of design should be in accordance with IS 11388. 1. 5. 3 References on Trashracks IS11388 – â€Å"Recommendations for Design of Trashracks for Intakes†. ASCE (1995) –â€Å"Guidelines for Design of Intakes for Hydroelectric Plants†. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  20 DRAWINGS: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  21 AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  22 2. HYDRAULIC DESIGN OF WATERWAYS The waterways or water conduction system is the system of canals, aqueducts, tunnels, inverted siphons and pipelines connecting the head works with the forebay tank. This Section provides guidelines and norms for the hydraulic design of these structures. 2. 1 2. 1. 1 CANALS Canals for small hydro plants are typically constructed in masonry or reinforced concrete. Several typical cross section designs are shown below: AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  23 Lined canals in earth, if required, should be designed in accordance with Indian Standard: IS 10430. A further division of canal types is based on function: – Feeder canal to connect the head regulator (intake) to the desilter – Power canal to connect the desilter to the Forebay tank. 2. 1. 2 Feeder Canals 2. 1. 2. 1 Feeder canal hydraulic design shall be based on the following criteria: = Turbine flow (QT) + Desilter flushing flow (QF). Design flow (Qd) AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  24 2. 1. 2. 2 Scouring velocity: A sufficiently high velocity must be provided to prevent deposition of sediment within the canal. This (scouring) velocity can be determined from the following formulae: d 9/7 S C = 0. 66 6 / 7 n = 0. 015 q 1 1 ? VS = . R 2 / 3 . S C/ 2 n Where: Sc = Scouring slope d = Target sediment size (m) q = Flow per unit width (Q/W) (m/s/m) R = hydraulic radius (m) Vs = scouring velocity (m/s) n = Manning’s roughness coefficient 2. 1. 2. 3 Optimization: The optimum cross section dimensions, slope and velocity should be determined by economic analysis so as to minimize the total life time costs of capital, OM and head losses (as capitalized value). The economic parameters for this analysis should be chosen in consultation with the appropriate regional, state or central power authorities these parameters include: – Discount rate (i) – Escalation rate(e) – Plant load factor – Service life in years (n) – Annual O+M for canal (% of capital cost) – Value of energy losses (Rs/kWh). Also see Section 1. 7 of this Standard. The selected design would be based on the highest of Vs or Voptimum. . 1. 2. 4 Freeboard: A freeboard allowance above the steady state design water level is required to contain water safely within the canal in event of power outages or floods. A minimum of 0. 5 m is recommended. 2. 1. 3 Power Canals: Power canal design shall be based on the following criteria a) Design flow = total turbine flow (QT) b) Power canal design should be based on optimization of dimensions, slope and velocity, as explained in the previous section. For mini-hydro plants Q 2. 0 m3/s optimal geometric design dimensions for Type 1 (masonry construction) can be estimated by assuming a longitudinal slope of 0. 04 and a Manning’s n value of 0. 018. Masonry construction would normally be preferred for canals with widths (W) less than 2. 0 m (flow area = AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  25 2. 0 m2). For larger canals with flow areas greater than 2. 0m2, a Type 3, box culvert design would be preferred – based on economic analysis. c) Freeboard: A freeboard allowance above the steady state design level is required to contain water safety within the canal in event of power outages. The waterway in most SHP’s terminates in a Forebay tank. This tank is normally equipped with an escape weir to discharge surplus water or an escape weir is provided near to the forebay tank. For mini-hydro plants a minimum freeboard of 0. 50 m is recommended. The adequacy of the above minimum freeboard should be verified for the following conditions: †¢ Maximum flow in the power canal co-incident with sudden outage of the plant. †¢ Design flow plus margins for leakage losses (+0. 02 to +0. 05 QT) and above rated operation (+ 0. 1QT). †¢ Characteristics of head regulator flow control. The freeboard allowance may be reduced to 0. 5 m after taking these factors into consideration. The maximum water level occurring in the forebay tank can be determined from the weir equation governing flow in the escape weir. 2. 1. 4 Rejection Surge Designs which do not incorporate downstream escape weirs would be subject to the occurrence of a rejection surge in the canal on sudden turbine shutdown, giving above static water levels at the downs tream end, reducing to the static level at the upstream (entry) end of the water way. Methods for evaluating water level changes due to a rejection surge are explained in Section 2. 2. 2 / 7. 0 of this Standard. . 2 AQUEDUCTS Aqueducts are typically required where feeder or power canals pass over a gully or side stream valley. If the length of the aqueduct is relatively short the same channel dimensions as for the canal can be retained and there would be no change in hydraulic design. For longer aqueducts design would be based on economic analysis subject to the proviso that flow remains sub critical with NF ? 0. 8 in the flume sections. The following sketch shows the principal dimension of aqueduct entry and exit transitions and flume section. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  26 The changes in invert elevation across the entry and exit structures can be calculated by Bernouli’s equation as below: †¢ Entry transition – consider cross – section (1) and (2); V2 V2 Z 1 + D + 1 = Z 2 + d + 2 + hL 2g 2g and 2 †¢ b? V ? hL = 0. 10 ? 1 ? ?. 2 ? B ? 2g Z2 can be determined from the above equations, since all geometrical parameters are known. Flume – Sections (2) to (3) The slope of the flume section is determined from Manning’s equation 2 †¢ ? Vn ? ( S ) = ? 2 / 3 ? . A Manning’s n = 0. 018 is suggested for concrete channels. ?R ? Some designers increase this slope by 10% to provide a margin of safety on flow capacity of the flume. Exit transition – consider cross section (3) and (4): V2 V2 Z 3 + d + 3 = Z 4 + D + 4 + hL 2g 2g AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  27 and 2 b? V ? hL = 0. 20 ? 1 ? ?. 3 ? B ? 2g Z4 can be determined from the above equations, since all geometrical parameters are known. The same basic geometry can be adapted for transition between trapezoidal canals sections and rectangular flume section, using mean flow width (B) = A/D. . 3. INVERTED SYPHONS 2. 3. 1 Inverted syphons are used where it is more economical to route the waterway underneath an obstacle. The inverted syphon is made up of the following components: †¢ Entry structure †¢ Syphon barrels †¢ Exit structure †¢ Entry Structure: Hydraulic design of the entry structure is similar to the design of reservoir, canal and penstock intakes. Follow the guidelines given in Section 2. 2. 2/2. of this Standard. †¢ Syphon barrels: The syphon barrel dimensions are normally determined by optimization ? V? ? does not tudies, with the proviso that the Froude Number ? N F = ? gd ? ? ? exceed 0. 8. Invert elevations are determined by accounting for head losses from entry to exit of the structure using Bernouli’s equation. For reinforced concrete channels a Manning’s â€Å"n† value of 0. 018 is recommended. The head loss coefficients for mitre bends can be determined from USACE HDC 228. 2. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  28 AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  29 Exit structure: The exit structure is designed as a diverging transition to minimize head losses; the design is similar to the outlet transition from flume to canal as discu ssed in Subsection 2. 2. 2/2 of this Standard. The following sketches show the layout of a typical inverted siphon. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  30 2. 3. 2 Reference on Aqueducts and Inverted Syphons â€Å"Hydraulic Structures† By C. D. Smith University of Saskatchewan Saskatoon (SK) Canada 2. 4. LOW PRESSURE PIPELINES Low pressure pipelines may be employed as an alternative to pressurized box culverts, aqueducts or inverted syphons. Concrete, plastic and steel pipes are suitable depending on site conditions and economics. Steel pipe is often an attractive alternative in place of concrete aqueducts in the form of pipe bridges, since relatively large diameter pipe possesses significant inherent structural strength. Steel pipe (with stiffening rings, as necessary), concrete and plastic pipe also have significant resistance against external pressure, if buried, and offer alternatives to inverted syphons of reinforced concrete construction. Generally pressurized flow is preferred. The pipe profile should be chosen so that pressure is positive through out. If there is a high point in the line that could trap air on filling an air bleeder valve should be provided. Otherwise, hydraulic design for low pressure pipelines is similar to the requirements for inverted syphons. The choice of type of design; low pressure pipeline land pipeline material), inverted syphon or aqueduct, depends on economic and constructability considerations, in the context of a given SHP. Manning’s â€Å"n† Values for selected Pipe Materials Material Welded Steel Polyethylene (HDPE) Poly Vinyl Chloride (PVC) Asbestos Cement Cast iron Ductile iron Precast concrete pipe Manning’s â€Å"n† 0. 012 0. 009 0. 009 0. 011 0. 014 0. 015 0. 013(2) Note: (1) From Table 5. 4 Layman’s Guide Book – ESHA (2) From Ven T. Chow – Open Channel Hydraulics AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  31 2. 5. TUNNELS 2. 5. 1 Tunnels often provide an appropriate solution for water conveyance in mountainous areas. Tunnels for SHP are generally of two types. †¢ Unlined tunnels †¢ Concrete lined tunnels On SHP tunnels are usually used as part of the water ways system and not subject to high pressures. . 5. 2 Unlined tunnels: Unlined water tunnels can be used in areas of favourable geology where the following criteria are satisfied: a) Rock mass is adequately water tight. Rock surfaces are sound and not vulnerable to erosion (or erodible zones b) are suitably protected. The static water pressure do es not exceed the magnitude of the minor field c) rock stress. Controlled perimeter blasting is recommended in order to minimize over break and produce sound rock surfaces. Additionally, this construction approach tends to produce relatively uniform surfaces and minimizes the hydraulic roughness of the completed tunnel surfaces. Design velocities of 1. 5 to 2. 0 m/s on the mean AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  32 cross section area give optimal cross section design. It is normal practice to provide a 100mm thick reinforced concrete pavement over leveled and compacted tunnel muck in the invent of the tunnel. IS 4880: Part 3 provides additional guidance on the hydraulic design of tunnels and on the selection of appropriate Manning’s â€Å"n† values. 2. 5. 3 Lined Tunnels Where geological are unfavourable it is often necessary to provide concrete linings for support of rock surfaces. IS4880: Parts 1-7 give comprehensive guidelines on the design of lined tunnels. 2. 5. 4 High Pressure Tunnels Design of high pressure tunnels is not covered in this standard. For high pressure design, if required, the designer should consult an experienced geotechnical engineer or engineering geologist. For the purpose of this standard, high pressure design is defined as tunnels subject to water pressures in excess of 10m relative to the crown of the tunnels. 2. 5. 5 Reference on Tunnels IS Standards: IS 4880 â€Å"Code of Practice for the Design of Tunnels Conveying Water†. Other References: Norwegian Hydropower Tunnelling† (Third volume of collected papers) Norwegian Tunneling Society Trondheim, Norway. www. tunnel. no Notably: Development of Unlined Pressure Shafts and Tunnels in Norway, by Einar Broch. 2. 6. CULVERTS AND CROSS-DRAINAGE WORKS Small hydro projects constructed in hilly areas usually include a lengthy power canal routed along a hillside contour. Lateral inflows from streams and gullies intercepted by SHP canals often transport large sediments loads which must be prevented from entering the canal. The first line of defense is the canal upstream ditch which intercepts local lateral runoff. The flow in these chains must be periodically discharged or the drain capacity will be exceeded. Flow from these drains is usually evacuated via culverts passing underneath the canal. These culverts would normally be located where gullies or streams cross the canal alignment. The capacity of canal ditches should be decided taking into consideration the average distance between culverts. In the rare cases when distance between culverts is excessive, consideration should be given to diverting AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  33 itch flows across the canal in flumes or half round pipes to discharge over the downhill side of the canal at suitable locations. Culverts are usually required where the canal route crosses gullies or streams. Culverts at these points provide for flow separation between lateral inflows and canal inflows and often present the most economical solution for crossing small but steep v alley locations. It is recommended that culverts design be based on the following hydrological criteria. †¢ For mini hydro projects, 1 in 10 year flood (Q10) †¢ For small hydro projects, 1 in 25 year flood (Q25) Where it is practical to extract the necessary basin parameters, the procedures given in Section 1. 4 should be applied. Otherwise design flows should be estimated from field measurements of cross section area and longitudinal slope at representative cross section of the gully or side stream. A survivable design approach is further recommended with canal walls strengthened to allow local over topping without damage to the canal integrity when floods exceed the design flood values. Detailed hydraulic design should be based on information from reliable texts or design guidelines – such as: â€Å"Design of Small Bridges and Culverts† Goverdhanlal †¢ †¢ 2. 7 2. 7. 1 â€Å"Engineering and Design – Drainage and Erosion Control†. Engineering Manual EM 1110-3-136 U. S. Army Corps of Engineers (1984) www. usace. army. mil/publications/eng-manuals Manufacturer’s guides, notably: – American Concrete Pipe Association www. concrete-pipe. org â⠂¬â€œ Corrugated Steel Pipe Institute www. cspi. ca Power Canal Surges Power canals that are not provided with escape weirs near their downstream end will be subject to canal surges on rapid load rejections or load additions. The rejection surge will typically cause the downstream water level to rise above static level and may control the design of canal freeboard. For load additions there is a risk that the level will fall to critical at the downstream end and restrict the rate at which load can be taken on by the unit. The following formulae taken from IS 7916: 1992 can be used to estimate the magnitude of canal surges. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  34 Maximum surge height in a power channel due to load rejection may be calculated from the empirical formulae given below: For abrupt closure hmax = K 2 + 2 Kh For gradual closure within the period required for the first wave to travel twice the length of the channel: K hmax = + V . h / g 2 Where: hmax = maximum surge wave height, K = V2/2g = velocity head, V = mean velocity of flow, and area of cross sec tion h = effective depth = top width †¢ Maximum water level resulting from a rejection surge at the downstream of a canal: Maximum W. L. = Yo + hmax †¢ Minimum water level resulting from by a start up surge at the downstream end of a canal: Minimum W. L. = YS – hmax Where: Yo YS = steady state downstream water level static downstream water level. The maximum water level profile can be approximated by a straight line joining the maximum downstream water level to the reservoir level. 2. 7. 2 Canal Surges on Complex Waterways: For waterway systems comprising several different water conductor types, the above equations are not applicable. In such cases a more detailed type of analysis will be required. The U. S. National Weather Service FLDWAV computer program can be used to solved for the transient flow conditions in such cases (Helwig, 2002). 2. 7. 3 References IS Standards cited: IS 7916: 1992 â€Å"Open Channel – Code of Practice†. Other References â€Å"Application of FLDWAV(Floodwave) Computer Model to Solve for Power Canal Rejection Wave for Simple and Complex Cases†. P. C. Helwig Canadian Society for Civil Engineering Proceedings, Annual Conference Montreal, Canada (2002). AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  35 3. HYDRAULIC DESIGN OF DESILTERS 3. 1 BACKGROUND Sediment transported in the flow, especially particles of hard materials such as quartz, can be harmful to turbine components. The severity of damage to equipment is a function of several variables, notably: sediment size, sediment hardness, particle shape, sediment concentration and plant head. The control of turbine wear problems due to silt erosion requires a comprehensive design approach in which sediment properties, turbine mechanical and hydraulic design, material selection and features to facilitate equipment maintenance are all considered (Naidu, 2004). Accordingly the design parameters for desilter design should be made in consultation with the mechanical designers and turbine manufacturer. Where the risk of damage is judged to be high a settling basin (or desilter) should be constructed in the plant waterway to remove particles, greater than a selected target size. 3. 1. 1 Need The first design decision is to determine whether the sediment load in the river of interest is sufficiently high to merit construction of a desilter. There is little guidance available on this topic; however, the following limits are suggested by Naidu (2004): Table 2. 2. 3/1. 0 Concentration Suggested Maximum Allowable Sediment versus Plant Head. Parameter Head Maximum allowable sediment concentration Low and Medium Head Turbines ? 150 m High Head Turbines 150 m 200 ppm 150 ppm 3. 1. 2 Removal Size There are also considerable divergences of opinion on the selection of design size for sediment removal. Nozaki (1985) suggests a size range of between 0. 3 mm to 0. 6 mm for plant heads ranging from 100 m to 300 m. Indian practice is to design for a particles size of 0. 20 m regardless of head. Some authors suggest that removal of particles smaller than 0. 20 mm is not practical. The adoption of 0. 20 mm is the design (target) sediment size is recommended for Indian SHP designs. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  36 3. 1. 3 Types of Desilters There are two basic types of desilters: Continuous flushing type Intermittent flushing type Guidelines for design of both types are given in this section. 3. 2. DESIGN CONSIDERATIONS 3. 2. 1 Data Requirements (Small Hydro Plants) It is recommended that a program of suspended sediment sampling be initiated near the intake site from an early stage during site investigations to ensure that sufficient data is available for design. The sampling program should extend through the entire rainy season and should comprise at least two readings daily. On glacier fed rivers where diurnal flow variations may exist, the schedule of sampling should be adjusted to take this phenomenon into account and the scheduled sampling times be adjusted to coincide with the hour of peak daily flow with another sample taken about twelve hours later. While it is often assumed that sediment load is directly related to flow, this is only true on the average, in a statistical sense. In fact it is quite likely, that the peak sediment event of a year may be associated with a unique upstream event such as a major landslide into the river. Such events often account for a disproportionately large proportion of the annual sediment flow. Therefore, it would also be desirable to design the sediment measurement program to provide more detailed information about such events, basically to increase the sampling frequency to one sample per 1 or 2 hours at these times. A five year long sediment collecting program would be ideal. Less than one monsoon season of data is considered unsatisfactory. Some authors suggest that the vertical variation of sediment concentration and variations horizontally across the river be measured. However, on fast flowing rivers inherent turbulence should ensure uniform mixing and sampling at one representative point should be sufficient. The data collected in a sediment sampling program should include: †¢ Mean daily concentration of suspended sediment (average of two readings twelve hours apart) †¢ Water temperature †¢ Flow (from a related flow gauging program) The following additional information can then be derived from collected samples. AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  37 †¢ †¢ †¢ A sediment rating curve (sediment concentration versus flow – where possible) Particle size gradation curve on combined sample Specific gravity of particles. It is also recommended that a petrographic analysis be carried out to identify the component minerals of the sediment mix. It is likewise recommended that experiments be made on selected ranges of particles sizes to determine settling velocities. A further discussion on the subject of sediment sampling is given in Avery (1989) The characteristics of the sediment on a given river as obtained from a data collection program will assist in selection of appropriate design criteria. 3. 2. 2 Data Requirements (Mini Hydro Plants) On mini hydro projects where resources and time may not be available to undertake a comprehensive sampling program, selection of design parameters will depend to a great extent on engineering judgment, supplemented by observations on site and local information. The following regional formula by Garde and Kothyari (1985) can be used to support engineering decision making. 0. 19 ?P ? 0 Vs = 530. 0 P0. 6. Fe1. . S0. 25 Dd . 10 .? max ? ?P? Where Vs = mean sediment load in (tonnes/km2/year) s = average slope (m/m) Dd = drainage density, as total length of streams divided by catchment area (km/km2) P = mean annual precipitation (cm) Pmax = average precipitation for wettest month (cm) Fe = ground cover factor, as below: 1 Fe = [0. 80 AA + 0. 60 AG + 0. 30 AF + 0. 10 AW ] ? Ai = arable land area AA = grass land area (all in km2) AG AF = forested area AW = waste land area (bare rock) 3. 2. 3 Design Criteria The principle design criteria are: 1. The target size for removal (d): d = 0. 20 mm is recommended 2. Flushing flow: QF = 0. 2 QP is recommended 3. Total (design) flow: QT = QP + QF = 1. 2 QP. Where QP is plant flow capacity in (m3/s). AHEC/MNRE/SHP Standards/ Civil Works – Guidelines For Hydraulic Design Of Small Hydro Plants /May 2011  Ã‚  38 3. 2. 4 Siting The following factors control site selection 1. A site along the water way of appropriate size and relatively level with respect to cross section topography 2. A site high enough above river level to provide adequate head for flushing. For preliminary layout a reference river level corresponding to the mean annual flood and minimum flushing head of 1. 0 m is recommended. In principle a desilting tank can be located anywhere along the water conductor system, upstream of the penstock intake. Sometimes it is convenient to locate the desilting basin at the downstream end of the waterway system where the desilter can also provide the functions of a forebay tank. However, a location as close to the head works is normally pref erred, site topography permitting. 3. 3 Hydraulic Design A desilter is made up of the following elements: †¢ Inlet section Settling tank †¢ Outlet section †¢ †¢ Flushing system 3. 3. 1 How to cite Hydraulic Design of Small Hydro Plants, Essay examples

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A look at the rights of the consumer and an assessment of proving whether a retailer is liable for faulty goods. The following paper examines whether a retailer, specifically TV World Ltd. is reliable for faulty tv sets, under the Sale of Goods Act 1979. The writer discusses the case study presented where TV World Ltd., a retail business, advertised a new 28 inch stereo television with teletext. The paper continues to examine how Ms. Hardy bought the television set for $300 but after a month it broke down. This paper asserts that Ms. Hardy signed a clause in the sales contract excluding liability under the Sale of Goods Act. The writer looks at a number of points had to be considered before establishing Ms. Hardys legal position. . Under section 12 of the Sale of Goods Act 1979 we can see that the TV World Ltd does have the right to sell the television in question. We will write a custom essay sample on Sale of Goods Act 1979 or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Section 13 ascertains that there is an implied condition that the goods will correspond with the description. Although Ms Hardy saw the TV in operation before he bought it, we can say that it was still bought by description as she was relying on the TV being a stereo model as described. TV World Ltd argues that as Ms Hardy should have realized that it was not a stereo model as she watched the set in the store. As Ms Hardy is just a consumer, she cannot be an expert in televisions and therefore it would be unfair to say that she should have known. We can see this in Beal v Taylor (1967) 3 ALL ER 253 where the plaintiff had inspected the car before she bought but later realized that it was an earlier model. The Court of Appeal held that the plaintiff was entitled to damages for breach of section 13 as she had relied on the description contained in the advertisement. Similar facts are found in the present situation and the goods have not corresponded to their description so TV World Lt d has breached section 13.