Overview of Hydro Power Sector in India

HYDRO POWER Power from force of moving water  Process of extracting ores by use of water waves is called hushing  A falling water column with sufficient head is used to generate compressed air & in turn power  Power =  Hydraulic power = η Q g h (for water dropping from height i.e. PE) = ρQ (for moving water i.e. KE)  Hydro electricity - electricity produced by hydropower i.e. power of falling water  Accounts for 20% of world electricity & 88% of renewable power till 2006  Rarely a hydro power station operates at its full capacity  Capacity Factor - ratio of annual average power produced to its installed capacity  Hydropower also called as white coal  Hoover dam - built in 1928 , generated 1345 MW , largest hydro electric power plant in 1936  Grand Coulee dam - built in 1948 , generate 6809 MW  Itaipu dam - built in 1984 , produced 14000 MW  Three gorges dam - built in 2008 , generate 22500 MW  Methods of generating hydro electricity  Conventional  makes use of dam  PE of dammed water is used to rotate turbine blades which in turn makes generator to produce electricity  Pumped storage  used to meet high peak demands by moving water b/w reservoirs at different elevations  used in large scale grid system  Run off the river              has small or no reservoir  running water from river is directly used to produce power without any storage Tidal power  makes use of tides in ocean Classification of Hydroelectricity facilities Large  above 25 MW (as per GOI)  Three Gorges Dam at 22.5 GW  Itaipu Dam at 14 GW  Guri Dam at 10.2 GW Small  20 to 25 MW (as per GOI)  Juthed & Titang small hydro power located in Chamba, HP  Total installed capacity of small hydro power in India is 2953 MW from 801 projects till 31/1/2011  serve as low cost renewable energy system  useful for supplying power to small industries & consumers Mini  10 to 20 MW (as per GOI) Micro  upto 10 MW capacity (as per GOI) Pico  upto 5 kW Related Equipments Penstock  enclosed pipes that supplies water to turbine in hydropower projects Turbines  rotary engine that takes energy from moving water  2 types a) reaction turbine b) impulse turbine Reaction Turbine  water pressure head acts on turbine blades & produce work  involves change in pressure  must be encased  Newton's third law describes transfer of energy  pressure drops occur both at fixed & moving heads  used in low & medium head application Impulse Turbine  change velocity of water jet  due to change in direction momentum changes which causes force in turbine  no change in water pressure occur  Newton's second law applies for transfer of energy  used in high head applications 0 140.79 88. Advantages of Hydro power  economical  less CO2 emission  reservoirs can be used for other purpose also  Disadvantages of Hydropower  eco system damage and loss of land  change in water levels  change in water course  emission of methane from reservoirs due to anaerobic decay of plant  Major hydro power producers of world (year 2009) Country China Canada Brazil US Russia Norway India Venezuela Japan Sweden Annual hydro production (TWh) 652.511 45.96 69.6 167.5 363.080 79.6 85.5 115.000 27.05 369.8 250.2 65.528 33.5 Installed capacity (GW) 196.229 16.974 69.600 14.209 .622 27. Hydropower and India  Union minister of power . Shushil Kumar Shinde  Union minister of new & renewable energy .Mr.Mr Farqoo Abdulla . Maharastra.wG Handri-neeva Mylavaram Dam Koil sagar Dam PABR Dam MPR Dam Chhatisgarh     gangrel Dam Hasdeo Bango Dam sondur Dam Dudhawa Dam . Chattisghad Pulichintala on the river Krishna in Guntur district Ellammpalli Singur Dam Dummagudem Sunkesula Musi Reservoir pothireddy padunear kund Ramagundam Dam on the river Godavari in [[Karimnagar District] Pranahita Chevella on the river Godavari in Adilabad District Jeri Dam Brmham sagar Polavaram. List of Dams in India Andhra Pradesh                                     Dowleswaram Barrage on the Godavari River in the East Godavari district Joorala Reservoir on the Krishna River Nagarjuna Sagar Dam on the Krishna River in the [Nalgonda district] Osman Sagar Reservoir on the [Musi River] Nizam Sagar Reservoir on the Manjira River in the [Nizamabad district] Prakasham Barrage on the Krishna River Sriram Sagar Reservoir Reservoir on the Godavari River Srisailam Dam on the Krishna River in the Kurnool district Rajolibanda Dam Telugu Ganga Polavaram Project on Godavari River Koil Sagar Lower Maneru Reservoir on the canal of Sriramsagar Project(SRSP) in '''Karimnagar''' District Himayath Sagar Reservoir Dindi Reservoir Somasila Gandipalem Reservoir Tatipudi Reservoir Inchampalli on the river Godavari and an inter state project Andhra pradesh. I & II on the Jhelum River near Uri in the Baramula district Nimoo Bazgo Project at village Alchi Dumkhar Hydroelectric Dam Project on Leh.Khalsi Batalik road Chutak on River Suru Kishanganga Hydropower project on the Kishanganga River Bursar Dam on Marusudar River in Doda District Jharkhand        Maithon Dam on Barakar River at Dhanbad Chandil Dam on Swarnarekha River near Chandil Palna Dam on Swarnarekha River near Chandil Konar Dam on Konar River Panchet on Damodar River Garga dam on Garga river Tilaiya Dam on Barakar River Karnataka  Hidkal Jalashaya (Dam) across Ghataprabha .Gujarat        Dantiwada Dam on Banas River in Banaskantha district Dharoi Dam on Sabarmati River near Dharoi Sukhi Dam on Sukhi River Sardar Sarovar Dam or Narmada Dam on the Narmada River Ukai Dam near Surat on Tapi river Kakrapar Dam near Surat on Tapi river Vasana Berej on Sabarmati River near Ahmedabad Himachal Pradesh + Punjab        Baira siul on Ravi River near Chamba Bhakra Nangal Dam on Satluj River near the border between Punjab and Himachal Pradesh Chamera Dam on Ravi River in the Chamba district of Himachal Pradesh Nathpa Dam on Sutlej River in the Kinnaur and Shimla districts of Himachal Pradesh Pong Dam Reservoir on Beas River in the Kangra district of Himachal Pradesh Pandoh Dam on Beas River in the Mandi district of Himachal Pradesh Ranjeet Sagar Dam on Raavi River in the Gurdaspur District of Punjab Jammu & Kashmir             Baglihar Dam on the Chenab River in the southern Doda district Dulhasti Hydroelectric Project on the Chenab River in the Kishtwar district Salal Hydroelectric Project on the Chenab River Kirthai Dam on Chenab River Sawalkot Dam on Chenab River Pakal-Dul Dam on Chenab River Uri Hydroelectric Project . P Dam Chikahole Dam. (Marikanive). Tumkur Dist Thippagondanahalli Reservoir Kanva Reservoir Vani Vilasa Sagara. Mysore Dist Nugu Dam. Chamarajnagar Taraka Reservoir. Chamarajnagar Suvarnawathi Dam. Kodagu Dist Narayanpur Dam downstream of Alamatti Dam Garura Dam Krishna River Hemavathi Reservoir (Gorur Dam). Mysore Dist Chakra Dam on the Chakra river Kerala                  Banasura Sagar Dam on Kabini River in the Wayanad District Malampuzha Dam on Malampuzha river in the Palakkad District Peechi Dam Vazhani dam Mangalam Dam Mattupetty Dam Kundala dam in Munnar Parambikulam Dam on the Parambikulam River Pothundi Dam Walayar Dam on the Walayar River Idukki arch dam on the Periyar River Idamalayar Dam Mullaperiyar Dam on the Periyar River Pazhassi Dam on Iritty River in the Kannur District Malankara Dam Neyyar Dam Siruvani Dam .D. H. Beerwal.                               Dhupdal Reservoir across Ghataprabha Krishna Raja Sagara Dam on Kaveri River Alamatti Dam across Krishna Basava Sagara Dam Lingsugur Linganamakki Dam on Sharavathi River Supa Dam Kodasalli Dam Kadra Dam Tunga Bhadra Dam Kabini Reservoir Beechanahalli.D Kote. Mysore Dist Harangi Reservoir Kushalnagar.Kote.Kote. Hassan Dist Naviltheertha Dam across Malaprabha Nethravathi river Linganmakki Dam across Sharavathi River Gajanuru Dam across Tunga river Lakkavali Dam across Bhadra river Manchinabeli Dam Marconhalli Dam. H.D. Kunigal. Hiriyur.R. Chitradurga Dist Kempu Hole Dam B. H. Nashik Dhom Dam-Krishna River[Wai]SATARA Ozarkhed Dam.River Mula Akkalpada Dam .River Pawna Wilson Dam .Ambi River Radhanagari Bhatsa Tansa Vaitarna Pawna .River Panjra(Dhule).River Pravara Gangapur Dam.Venna River . Rahuri .River Bhima Mulshi Dam .[SATARA] Koyna Dam .Koyna River Jayakwadi dam on River Godavari Ujani .River Mula Khadakwasla .River Mutha Kolkewadi Dam Panshet .      Meenkara Dam Kanjhirapuzha Chulliyar Dam Jeevana dam Asurankundu Dam thenmala Dam Madhya Pradesh                Bansagar Dam on Son River in the Shahdol District Bargi Dam on Narmada River in the Jabalpur District Gandhi Sagar Dam on Chambal River in the Mandsaur District Indirasagar on Narmada River in the Khandwa District Madikheda Dam on Sindh River in the Shivpuri District Rajghat Dam on Betwa River in the Ashoknagar District Tawa Reservoir on Tawa River in the Hoshangabad District tigra dam on sank river in the gwalior district Barna Dam halali dam kolar dam kerwa dam Omkareshwar Dam on narmada tippa jhariya Dam omkareshwar project on narmada river in khargon district Maharashtra Main article: Dams in Maharashtra                     Mula Dam.[In progress] Kanehar Dam . Nashik Karanjwan Dam . Tehsil-Nimbahera. Koraput District Indravati Dam on river Indravati in kalahandi district Salia dam on river Kharkhari in Ganjam District SATKOSIA (ANGUL) Rajasthan             Jawai Dam Jawahar Sagar Dam Kota Barrage Rana Pratap Sagar dam on Chambal River Sukali dam on Sukali river at Selvada Meja Dam on Kothari river Morel Dam on Morel River Pong Dam on Vyas River Mahi Bajaj Sagar Dam on Mahi River Bisalpur Dam Project on Banas River Gambhiri Dam on Gambhiri River at Aranoda village.             Nandur Madhmeshwar Dam Gose dam . chittorgarh ((meja dam )) in Bhilwara District Sikkim   Teesta-V Dam Rangit Dam Tamil Nadu     Aliyar Reservoir Amaravathi Reservoir Amaravathi Dam Anaikuttam Reservoir . Dist.bhandara dist Yeldari Dam on Purna River Near Parbhani Siddheshwar Dam on Purna River Near Parbhani Manjara On River Manjara Near Latur Girna Dam On River Girna Chaskaman On River Bhima Near Rajgurunagar Pravara On River Godavari Isapur Dam On River Painganga River Yedgaon Dam on river kukadi Varasgaon on river Mose Temghar on river Mutha Pavnanagar on Pavna River Orissa       Balimela Reservoir Hirakud Dam on Mahanadi River near Sambalpur Jalaput on Machkund River near Jaypore.                                                    Anainaduvu Reservoir Bhavanisagar Reservoir Chittar Reservoir Chittar Reservoir-1 Chittar Reservoir-2 Gatana Reservoir Golwarpatti Reservoir Gomukhinadhi Reservoir Gundar Reservoir Gunderippalam Reservoir Kallanai Anaicut Kariakoil Reservoir Karupppanadhi Reservoir Kelavarapalli Reservoir Kesarigulihalla Reservoir Kodaganar Reservoir Kodiveri Dam Kovilar Reservoir Krishnagiri Reservoir Kullursandai Reservoir Kutharaiyar Reservoir Lower Nirar Reservoir Manimukthanadhi Reservoir Manimuthar Reservoir Manjalar Reservoir Marudhanadhi Reservoir Mettur Dam on Kaveri River Nagavathi Reservoir Noyyal Oarathuppalayam Palar Porandalar Reservoir Pambar Reservoir Parappalar Reservoir Pechiparai Reservoir Periyar Reservoir (Pilavukkal Project) Perumpallam Reservoir Perunchani Reservoir Peruvaripallam Ponnaniar Reservoir Ramanadhi Reservoir Sathanur Reservoir Sholayar Reservoir Siddhamalli Reservoir Soolagiri chinnar Reservoir Stanley Reservoir Thambalahalli Reservoir Thirumurthi Reservoir Thoppaiyar Reservoir Thunakadavu Reservoir Uppar Reservoir Upper Nirar Wier Vaigai Dam . Nalgonda District of Andhra Pradesh.         Vaigai Reservoir Vaniyar Reservoir Varadamanadhi Reservoir Varattupallam Reservoir Vattamalaikarai Odai Reservoir Vembakottai Reservoir Vidur Reservoir Willingdon Reservoir Karaiyar Reservoir Uttar Pradesh              Parichha Dam on Betwa River in Jhansi District Matatila Dam on Betwa River in Lalitpur District Govind Ballabh Pant Sagar on Rihand River in Sonbhadra Jamni Dam on Jamni River in Lalitpur District Ramganga Dam on Ramganga River in Kalagarh Rohini Dam on Rohini River in Lalitpur District Shahzad Dam on Shahzad River in Lalitpur District Govind Sagar Dam on Shahzad River in Lalitpur District Sajnam Dam on Sajnam River in Lalitpur District Sukma-Dukma Dam a below water construction on Betwa River near Jhansi District Jirgo reservoir on Jirgo river in mirzapurUttar Pradesh Musa Kahand on Karmnasa river]] in chaundali district Uttar Pradesh Chittaurgarh dam Balrampur Dist. between 1955 and . India.UP Uttarakhand            Tehri Dam on Bhagirathi River Dhauliganga dam Vishnuprayag Lakhwar Tanakpur Dam Haripura dam BAUR DAM Tumaria dam Nanaksager dam BEGUL DAM Birahi Ganga Hydro Power Ltd West Bengal  Farakka Barrage on Ganges River Nagarjuna Sagar Dam  Nagarjuna Sagar Dam (Telugu: నాగార్జనసాగర్ ఆనకట్ట ) is the world's largest masonry dam built across ు Krishna River in Nagarjuna Sagar. it also is one of the earliest multi-purpose irrigation and hydro-electric projects in India.25 m. Critics maintain that its negative environmental impacts outweigh its benefits. Punjab .900 sq mi).55 m (740 ft) high next to the 261m Tehri Dam also in India. enough to drain the whole of Chandigarh.5 m (448 ft). Gujarat. wide and 45 ft (14 m).6 km long with 26 gates which are 42 ft (13 m). parts of Haryana. It has a proposed final height of 136. The length of the dam (measured from the road above it) is 518. and is near the border between Punjab and Himachal Pradesh in northern India. The dam provides irrigation water to the Nalgonda District. Khammam District and Guntur District and electric power to the national grid. Bhakra Dam Bhakra Dam is a concrete gravity dam across the Sutlej River. The dam is the largest dam in and part of the Narmada Valley Project. stores up to 9340 million cu m of water. Its reservoir.  Of the thirty large dams planned on river Narmada. The project took form in 1979 as part of a development scheme to increase irrigation and produce hydroelectricity. Prakasam District.[2] Nagarjuna Sagar was the earliest in the series of large infrastructure projects initiated for the Green Revolution in India. The dam contains the Nagarjuna Sagar reservoir with a capacity of up to 11.1 m broad. known as the "Gobind Sagar".472 million cubic metres. a large hydraulic engineering project involving the construction of a series of large irrigation and hydroelectric multi purpose dams on the Narmada River. It has created discord between its government planners and the citizens group Narmada Bachao Andolan.1967. The project will irrigate more than 18. India.000 km2 (6.   o o o o  o o Catchment Area : 215000 km² (83012 sq mi) Masonry dam Spillway of dam : 471 m Non-over flow dam : 979 m Length of Masonry dam : 1450 m Maximum height : 125 m Earth dam Total Length of Earth dam : 3414 m Maximum height : 28 m Sardar Sarovar Dam  The Sardar Sarovar Dam is a dam on the Narmada River near Navagam. tall and 1. The dam is 490 ft (150 m). is Asia's second highest at 225. The dam. most of it in drought prone areas of Kutch and Saurashtra. Sardar Sarovar Dam (SSD) is the largest structure to be built. tall. located at a gorge near the (now submerged) upstream Bhakra village in Bilaspur district of Himachal Pradesh. it is 9. Kuravanmala (839 feet) and Kurathimala (925 feet). Built in 1957.[1] Technically. At 167. It was constructed and is owned by the Kerala State Electricity Board. it is one of the highest arch dams in Asia. about 15 km from Sambalpur in the state of Orissa in India.[1] Behind the dam extends a lake.and Delhi. Hirakud Reservoir. The stored water is used to produce electricity at the Moolamattom Power house. It is one of the first major multipurpose river valley project started after India's independence. Described as 'New Temple of Resurgent India' by Jawaharlal Nehru. the dam attracts tourists from all over India. It is built on the Periyar River. 55 km long. It started generating power on 4 October 1975. The dam stands between the two mountains . at 555 feet in height. Sometimes both the dams together are called Bhakra-Nangal dam though they are two separate dams. The 90 km long reservoir created by the Bhakra Dam is spread over an area of 168. the dam type is a concrete double. it withholds the second largest reservoir in India.35 km2. the three dams have created an artificial lake that is 60 km² wide. Idukki Dam The Idukki Dam. In terms of storage of water. Rana Pratap Sagar Dam The Rana Pratap Sagar Dam is a gravity masonry dam of 53. India.[2] This dam was constructed along with two other dams at Cheruthony and Kulamavu.8 metres (177 ft) height built on the Chambal River at Rawatbhata in Rajasthan in India. Nangal dam is another dam downstream of Bhakra dam. located in Kerala.22 billion cu m. the first being Indira Sagar dam in Madhya Pradesh with capacity of 12. in the ravine between the Kuravan and Kurathi Hills in Kerala. is currently the 14th largest arch dam in Asia. The Government of Canada aided in the building of the dam with long term loans and grants. which is located inside nearby rocky caves. Hirakud Dam is one of the longest dams in the world. thin arc dam. The name of the dam is mostly mis-pronounced in North India as Hirakund which is actually Hirakud.[1][2][3] . about 16 mi (26 km) in length. It is part of integrated scheme of a cascade development of the river involving four projects starting with the Gandhi Sagar Dam in the upstream reach (48 kilometres (30 mi) upstream) in Madhya Pradesh and the Jawahar Sagar Dam on the downstream (28 kilometres (17 mi) downstream) with a terminal structure of the Kota Barrage (28 kilometres (17 mi) further downstream) in Rajasthan for irrigation.[1] the first prime minister of India. the dam is one of the world's longest earthen dam. India.[1] Hirakud Dam Hirakud Dam (Oriya: ହୀରାକୁ ଦ ବନ୍ଧ) is built across the Mahanadi River. curvature parabolic.68 metres. Together. Wildhorse Dam near Mountain City. The normal component of the weight of the arch ring may be taken by the arch action. this subtended angle is kept a constant and the variation in distance between the abutments at various levels are taken care of by varying the radii.5 kilometres (10. Jones Falls Dam.240 metres (7. This method of construction minimizes the amount of concrete necessary for construction but transmits large loads to the foundation and abutments.3 mi) from the border with Bangladesh near Chapai Nawabganj District.0 GWh of generation has been exceeded in most years since its commissioning. is a constant radius dam. roughly 16. firm reliable supports at the abutments (either buttress or canyon side wall) are more important. also known as a variable radius dam.  The multiple-arch dam consists of a number of single-arch dams with concrete buttresses as the supporting abutments. while the distribution of the normal hydrostatic pressure between vertical cantilever and arch action will depend upon the stiffness of the dam in a vertical and horizontal direction. as for example the Daniel-Johnson Dam. Constant-radius dams are much less common than constant-angle dams.350 ft) long. Nevada in the United States is an example of the type. In a constant-angle dam. namely the constant-angle and the constantradius dam. The dam and power plant are named after the warrior Maharaja Rana Pratap of Rajasthan. located in the Indian state of West Bengal. the then Prime Minister of India.  A similar type is the double-curvature or thin-shell dam.The direct benefit from the dam is hydropower generation of 172 MW (with four units of 43 MW capacity each) at the dam toe powerhouse adjoining the spillway. which means that as the channel grows narrower towards the bottom of the dam the central angle subtended by the face of the dam becomes smaller. Québec.[27] The safety of an arch dam is dependent on the strength of the side wall abutments. The Power Station was officially declared open on 9 February 1970 by Indira Gandhi. Parker Dam is a constant-angle arch dam. If the upstream face is vertical the entire weight of the dam must be carried to the foundation by gravity.  Two types of single-arch dams are in use. The estimated generation potential of 473. The multiple-arch dam does not require as many buttresses as the . while the normal hydrostatic pressure will be distributed as described above.[4][3] Farakka Barrage Farakka Barrage is a barrage across the Ganges River. in Canada. Canada. 1975. Operations began on April 21. Construction was started in 1961 and completed in 1975. The constant-radius type employs the same face radius at all elevations of the dam. The barrage is about 2. The most desirable place for an arch dam is a narrow canyon with steep side walls composed of sound rock.[1]  Types of dams Arch dams  In the arch dam. hence not only should the arch be well seated on the side walls but also the character of the rock should be carefully inspected. The feeder canal from the barrage to the Bhagirathi-Hooghly River is about 25 miles (40 km) long. When the upstream face is sloped the distribution is more complicated. The appearance is similar to a single-arch dam but with a distinct vertical curvature to it as well lending it the vague appearance of a concave lens as viewed from downstream. with releases received from the Gandhi Sagar Dam and the additional storage created at the dam by the intercepted catchment area. For this type of dam. stability is obtained by a combination of arch and gravity action. but the buttresses are inflexible and prevent the dam from falling over. stability is secured by making it of such a size and shape that it will resist overturning. The core of the dam is zoned depending on the availability of locally available materials. [28] In a gravity dam. though the hollow dam is frequently more economical to construct. the dam cross section is usually designed so that the resultant falls within the middle at all elevations of the cross section (the core). the force that holds the dam in place against the push from the water is Earths gravity pulling down on the weight of the dam itself. For this type of dam. in order to prevent tensile stress at the upstream face and excessive compressive stress at the downstream face. pushing the dam into the ground. but requires good rock foundation because the buttress loads are heavy. foundation conditions and the material attributes. is smaller than the moment caused by the weight of the dam[clarification needed]." Grand Coulee Dam is a solid gravity dam and Itaipu Dam is a hollow gravity dam. The Romans were the first to use buttresses to increase the stability of a dam wall. Buttress dam A buttress dam or hollow dam is a dam with a solid. sliding and crushing at the toe. impervious foundations with high bearing strength are essential. When situated on a suitable site.[2] Buttress dams were originally built to retain water for irrigation or mining in areas of scarce or expensive resources but cheap labour. Gravity dams In a gravity dam. However. Gravity dams are classified as "solid" or "hollow" and are generally made of either concrete or masonry.[1] The dam wall may be flat or curved. gravity dams can prove to be a better alternative to other types of dams. The solid form is the more widely used of the two. The dam will not overturn provided that the moment around the turning point. Water pushes against the dam. Since the fear of flood is a strong motivator in many regions. the gravity dam probably represents the best developed example of dam building. This is the case if the resultant force of water pressure and weight falls within the base of the dam. gravity dams are being built in some instances where an arch dam would have been more economical. the virtues and weaknesses of the buttress type dams have become apparent. caused by the water pressure.hollow gravity type. When built on a carefully studied foundation. This is called "zoning". water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses or supports. A buttress dam is a good choice in wide valleys where solid rock is rare. Most buttress dams are made of reinforced concrete and are heavy.[3] As designs have become more sophisticated.[4] . Gravity dams can also be classified as "overflow" (spillway) and "non-overflow. . which is a shaft or drum with blades attached. a "U"-shaped cofferdam is used in the construction one half of a dam. with components consisting of sheet piles. Torch cutting of the hull is done inside a cofferdam attached directly to the hull of the ship. The cofferdam is later replaced while the hull sections are welded together again. the cofferdam is removed and a similar one is created on the opposite side of the river for the construction of the dam's other half. wales. These cofferdams are typically a conventional embankment dam of both earth. or in pairs across. and is then detached before the hull sections are floated apart. In some cases a ship is actually cut in two while still in the water. steam. These cofferdams are usually welded steel structures. Modern steam turbines frequently employ both reaction and impulse in the same unit. Such structures are typically dismantled after the ultimate work is completed. Dependent upon the the geography of a dam site. An example of such an application is certain ship lengthening operations. Typically. a body of water and constructed to allow the enclosed area to be pumped out. typically varying the degree of reaction and impulse from the blade root to its periphery. a rotor assembly. Turbine A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work. one upstream and one downstream of the proposed dam. See also caisson. two cofferdams are usually built. Early turbine examples are windmills and water wheels. in some applications. upon completion of the dam and associated structures. for invention of the impulse turbine.and rock-fill. Credit for invention of the steam turbine is given both to the British engineer Sir Charles Parsons (1854–1931).Cofferdam A cofferdam (also called a coffer[1]) is a temporary enclosure built within. but concrete or some sheet piling also may be used. and water turbines usually have a casing around the blades that contains and controls the working fluid. Gas. Moving fluid acts on the blades. The cofferdam is also used on occasion in the shipbuilding and ship repair industry. As expensive as this may be to accomplish. bridge piers and other support structures built within or over water. use of a drydock may be even more expensive. when it is not practical to put a ship in drydock for repair or alteration. For dam construction. and cross braces. Enclosed coffers are commonly used for construction and repair of Oil platforms. The simplest turbines have one moving part. When complete. for invention of the reaction turbine and to Swedish engineer Gustaf de Laval (1845–1913). after an alternative diversion tunnel or channel has been provided for the river flow to bypass the dam foundation area. and a new section of ship is floated in to lengthen the ship. or the blades react to the flow. the downstream coffer is removed and the upstream coffer is flooded as the diversion is closed and the reservoir begins to fill. creating a dry work environment for the major work to proceed. so that they move and impart rotational energy to the rotor. the fluid's pressure head is changed to velocity head by accelerating the fluid with a nozzle. Whilst this makes the Parsons turbine much longer and heavier. Francis turbines and most steam turbines use this concept. multiple turbine stages are usually used to harness the expanding gas efficiently. for the same degree of thermal energy conversion. The axial compressor in many gas turbine engines is a common example. Benoit Fourneyron. Claude Burdin coined the term from the Latin turbo. a Parsons type reaction turbine would require approximately double the number of blade rows as a de Laval type impulse turbine. The fluid may be compressible or incompressible. Several physical principles are employed by turbines to collect this energy: Impulse turbines These turbines change the direction of flow of a high velocity fluid or gas jet. Newton's second law describes the transfer of energy for impulse turbines. The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. in modern axial compressors. such as would be used for marine applications or for land-based electricity generation. Pelton wheels and de Laval turbines use this process exclusively. A pressure casement is needed to contain the working fluid as it acts on the turbine stage(s) or the turbine must be fully immersed in the fluid flow (such as with wind turbines). Impulse turbines do not require a pressure casement around the rotor since the fluid jet is created by the nozzle prior to reaching the blading on the rotor. Here again. The pressure of the gas or fluid changes as it passes through the turbine rotor blades. all the pressure drop takes place in the stationary blades (the nozzles). built the first practical water turbine. driven. In the case of steam turbines. maintains the suction imparted by the draft tube.. Newton's third law describes the transfer of energy for reaction turbines. i. a student of Claude Burdin. the overall efficiency of a reaction turbine is slightly higher than the equivalent impulse turbine for the same thermal energy conversion. For compressible working fluids. as in the case of a steam or gas turbine. is a compressor or pump. the degree of reaction and impulse typically vary from the blade root to its periphery.A device similar to a turbine but operating in reverse. both reaction and impulse are employed and again. Before reaching the turbine. Theory of operation A working fluid contains potential energy (pressure head) and kinetic energy (velocity head).e. There is no pressure change of the fluid or gas in the turbine blades (the moving blades). for water turbines. or vortex. during an 1828 engineering competition. . Reaction turbines These turbines develop torque by reacting to the gas or fluid's pressure or mass. The casing contains and directs the working fluid and. relative to the rotor. However. Wind turbines also gain some energy from the impulse of the wind. Vector analysis related the fluid flow with turbine shape and rotation. Mean performance for the stage can be calculated from the velocity triangles. Crossflow turbines are designed as an impulse machine. As the volume increases. Formulae for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow condition. Graphical calculation methods were used at first. in absolute terms the rotor exit velocity is Va2. Wind turbines use an airfoil to generate lift from the moving fluid and impart it to the rotor (this is a form of reaction). at velocity Vr2. simplifying assumptions were made. and the base of the blade spins at a slower speed relative to the tip. with a nozzle. tip. Relative to the rotor. As with most engineering calculations. modern turbine designs use both reaction and impulse concepts to varying degrees whenever possible.Steam turbines and later. Velocity triangles can be constructed at any section through the blading (for example: hub . The rotor rotates at velocity U. the velocity of the gas as it impinges on the rotor entrance is Vr1. Steam Turbines were traditionally more impulse but continue to move towards reaction designs similar to those used in Gas Turbines. like a traditional water wheel. to a high reaction style tip. midsection and so on) but are usually shown at the mean stage radius. Some of the calculations are empirical or 'rule of thumb' formulae. using the Euler equation: Hence: where: specific enthalpy drop across stage turbine entry total (or stagnation) temperature turbine rotor peripheral velocity . continue to do so and in practice. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The reason is due to the effect of the rotation speed for each blade. Turbines with multiple stages may utilize either reaction or impulse blading at high pressure. Velocity triangles can be used to calculate the basic performance of a turbine stage. The gas is turned by the rotor and exits. and others are based on classical mechanics. At low pressure the operating fluid medium expands in volume for small reductions in pressure. Classical turbine design methods were developed in the mid 19th century. the blade height increases. This change in speed forces a designer to change from impulse at the base. by deflecting it at an angle. gas turbines developed continually during the 20th Century. The velocity triangles are constructed using these various velocity vectors. but in low head applications maintain some efficiency through reaction. at this radius. Under these conditions (termed Low Pressure Turbines) blading becomes strictly a reaction type design with the base of the blade solely impulse. causing the runner to spin. Francis turbine The Francis turbine is a type of water turbine that was developed by James B. Massachusetts. A casement is needed to contain the water flow. Francis in Lowell. The Francis turbine is a reaction turbine.change in whirl velocity The turbine pressure ratio is a function of and the turbine efficiency. known as a runner. These tools have led to steady improvements in turbine design over the last forty years. As the water moves through the runner. the specific speed can be calculated and an appropriate turbine design selected. further acting on the runner. giving up its energy. which means that the working fluid changes pressure as it moves through the turbine. The specific speed is derived to be independent of turbine size. The turbine is located between the high-pressure water source and the low-pressure water exit. The speed range of the turbine is from 83 to 1000 rpm. This radial flow acts on the runner's vanes.[1] It is an inward-flow reaction turbine that combines radial and axial flow concepts. but normally they have horizontal shaft. if the string is pulled short. This . Vertical shaft may also be used for small size turbines. Modern turbine design carries the calculations further. though mini-hydro installations may be lower. They operate in a head range of ten meters to six hundred and fifty meters and are primarily used for electrical power production. the ball spins faster due to the conservation of angular momentum. usually at the base of a dam. Computational fluid dynamics dispenses with many of the simplifying assumptions used to derive classical formulas and computer software facilitates optimization. The power output generally ranges from 10 to 750 megawatts. The inlet is spiral shaped. along with some fundamental formulas can be used to reliably scale an existing design of known performance to a new size with corresponding performance. The guide vanes (or wicket gate) may be adjustable to allow efficient turbine operation for a range of water flow conditions. Medium size and larger Francis turbines are most often arranged with a vertical shaft. Runner diameters are between 1 and 10 meters. Given the fluid flow conditions and the desired shaft output speed. Off-design performance is normally displayed as a turbine map or characteristic. The specific speed. For an analogy. Guide vanes direct the water tangentially to the turbine wheel. Francis turbines are the most common water turbine in use today. imagine swinging a ball on a string around in a circle. its spinning radius decreases. This number describes the speed of the turbine at its maximum efficiency with respect to the power and flow rate. The primary numerical classification of a turbine is its specific speed. The outlet is a specially shaped draft tube that helps decelerate the water and recover kinetic energy. a critical element of Kaplan design is to maintain a positive seal to prevent emission of oil into the waterway. It was developed in 1913 by the Austrian professor Viktor Kaplan. The design combines radial and axial features. Because the propeller blades are rotated by high-pressure hydraulic oil. Current areas of research include CFD driven efficiency improvements and new designs that raise survival rates of fish passing through. however. but may be lower in very low head applications. Discharge of oil into rivers is not permitted. who combined automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and water level. which means that the working fluid changes pressure as it moves through the turbine and gives up its energy. Its invention allowed efficient power production in low-head applications that was not possible with Francis turbines. helps Francis and other inward-flow turbines harness water energy efficiently. The resulting pressure drop may lead to cavitation. Runner diameters are between 2 and 8 meters. in addition to the water's pressure. The Kaplan turbine was an evolution of the Francis turbine. A higher turbine location. Pelton wheel The Pelton wheel is an impulse turbine which is among the most efficient types of water turbines. The turbine does not need to be at the lowest point of water flow as long as the draft tube remains full of water. low-head power production The Kaplan turbine is an inward flow reaction turbine. as opposed to its weight like traditional overshot water wheel. The inlet is a scroll-shaped tube that wraps around the turbine's wicket gate. The range of the turbine is from 79 to 429 rpm. Kaplan turbines are now widely used throughout the world in high-flow. Water is directed tangentially through the wicket gate and spirals on to a propeller shaped runner. It was invented by Lester Allan Pelton in the 1870s. . Kaplan turbine efficiencies are typically over 90%. Kaplan turbine The Kaplan turbine is a propeller-type water turbine which has adjustable blades. The head ranges from 10-70 meters and the output from 5 to 120 MW. The Pelton wheel extracts energy from the impulse (momentum) of moving water. increases the suction that is imparted on the turbine blades by the draft tube.property. Variable geometry of the wicket gate and turbine blades allow efficient operation for a range of flow conditions. causing it to spin. Pelton wheels have only one turbine stage.[1] Specific speed Specific speed Ns is a quasi non-dimensional number used to classify pump impellers as to their type and proportions. and given the characteristically low specific speed of the Pelton.Although many variations of impulse turbines existed prior to Pelton's design. For maximum power and efficiency. the water leaving these wheels typically still had high speed. The formula suggests that the Pelton turbine is most suitable for applications with relatively high hydraulic head H. A very small percentage of the water's original kinetic energy will still remain in the water. Pelton's paddle geometry was designed so that when the rim runs at ½ the speed of the water jet. so ." This resulting unitless ratio may loosely be expressed as a "speed. Therefore. thus splitting the water jet in half (see photo). and helps to ensure smooth. which divides the actual performance figure to provide a unitless figure of merit. unlike gas turbines that operate with compressible fluid. This "impulse" does work on the turbine. In metric units flow may be in l/s or m³/s and head in m. The specific speed ns of a turbine dictates the turbine's shape in a way that is not related to its size. the turbine system is designed such that the water-jet velocity is twice the velocity of the bucket. however. thus allowing the water flow to continue uninterrupted. this allows the bucket to be emptied at the same rate it is filled. Often two buckets are mounted side-by-side. the water leaves the wheel with very little speed. In the process. due to the 5/4 exponent being greater than unity. and carried away much of the energy. and care must be taken to state the units used. the water's momentum is transferred to the turbine. This allows a new turbine design to be scaled from an existing design of known performance. The specific speed is also the main criterion for matching a specific hydroelectric site with the correct turbine type. and allowing for a very efficient turbine. the direction of the water velocity changes to follow the contour of the bucket. extracting almost all of its energy. This balances the side-load forces on the wheel. (see conservation of mass). the water exerts pressure on the bucket and the water is decelerated as it does a "u-turn" and flows out the other side of the bucket at low velocity." only because the performance of the reference ideal pump is linearly dependent on its speed. Because water and most liquids are nearly incompressible. efficient momentum transfer of the fluid jet to the turbine wheel. The resulting figure would more descriptively be called the "ideal-reference-device-specific performance. Performance is defined as the ratio of the pump or turbine against a reference pump or turbine. almost all of the available energy is extracted in the first stage of the hydraulic turbine. When the water-jet contacts the bucket. The water flows along the tangent to the path of the runner. As water flows into the bucket. Nozzles direct forceful streams of water against a series of spoon-shaped buckets mounted around the edge of a wheel. they were less efficient than Pelton's design. In Imperial units it is defined as the speed in revolutions per minute at which a geometrically similar impeller would operate if it were of such a size as to deliver one gallon per minute against one foot of hydraulic head. Several mathematical definitions of specific speed (all of them actually ideal-device-specific) have been created for different devices and applications. Radial impellers are generally low flow/high head designs whereas axial flow impellers are high flow/low head designs. e. Centrifugal pump impellers have specific speed values ranging from 500 to 10. mixed flow at 2000-8000 and axial flow pumps at 7000-20. where: Ns is specific speed (unitless) n is pump rotational speed (revolutions per seconds) Q is flowrate (m³/s) at the point of best efficiency H is total head (m) per stage at the point of best efficiency g is acceleration due to gravity (m/s²) Note that the units used affect the specific speed value and consistent units should be used for comparisons.g. with radial flow pumps at 500-4000.0 for a true axial flow impeller. the ratio of the impeller outlet diameter to the inlet or eye diameter decreases.000 or greater generates its head exclusively through axial forces. Pump specific speed Low-specific speed radial flow impellers develop hydraulic head principally through centrifugal force. Net suction specific speed . in order to produce the performance.000. instead of its reference speed of "1 unit. An axial flow or propeller pump with a specific speed of 10. Pumps of higher specific speeds develop head partly by centrifugal force and partly by axial force. Once the desired specific speed is known. basic dimensions of the unit's components can be easily calculated.that the ratio of [device-performance to reference-device-performance] is also the increased speed the reference device would need to turn. changing the values listed above." Specific speed is used in engineering design where it is thought of as an index used to predict desired pump or turbine characteristics.000 (English units). Often it is used to predict the type of pump or turbine required for a design flow rate and head. the general shape of a pump's impeller.. Pump specific speed can be calculated using British gallons or using Metric units (m3/s or L/s and metres head). This ratio becomes 1. As the specific speed increases. Values of specific speed less than 500 are associated with positive displacement pumps. (dimensioned parameter). Francis turbines fall in the range of 10 to 100. a Pelton wheel is typically around 4. The envelope of stable operation is defined in terms of the best efficiency point of the pump. n = rpm[citation needed] where: Ω = angular velocity (radians per second) Hn = Net head after turbine and waterway loss (m) Q = water flow (m³/s)  N = Wheel speed (rpm) . all in imperial units[5]. It is defined by centrifugal and axial pumps' inherent physical characteristics and operating point [2]. The net suction specific speed of a pump will define the range of operation in which a pump will experience stable operation [3] .The net suction specific speed is mainly used to see if there will be problems with cavitation during the pump's operation on the suction side [1]. This allows accurate calculations to be made of the turbine's performance for a range of heads. then the smaller the range of stable operation. The net suction specific speed is defined as[4]: where: Nss = net suction specific speed N = rotational speed of pump in rpm Q = flow of pump in US gallons per minute NPSHR = Net positive suction head (NPSH) required in feet at pump's best efficiency point Turbine specific speed The specific speed value (radian/second) for a turbine is the speed of a geometrically similar turbine which would produce one unit of he specific speed of a turbine is given by the manufacturer (along with other ratings) and will always refer to the point of maximum efficiency. typically ranging from 1 to 10. Well-designed efficient machines typically use the following values: Impulse turbines have the lowest ns values. while Kaplan turbines are at least 100 or more. The higher the net suction specific speed. The relief valve can be internal or external. The internal valve should in general only be used as a safety precaution. Liquid flows into the pump as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. Pumps fall into three major groups: direct lift. such as liquids. will produce the same flow at a given speed (RPM) no matter what the discharge pressure. an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended. Types Positive displacement pump A positive displacement pump causes a fluid to move trapping a fixed amount of it then forcing (displacing) that trapped volume into the discharge pipe. A pump displaces a volume by physical or mechanical action. A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. gases or slurries. or both. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase. Positive displacement types A positive displacement pump can be further classified according to the mechanism used to move the fluid: . The pump manufacturer normally has the option to supply internal relief or safety valves. until the line bursts or the pump is severely damaged.[1] Their names describe the method for moving a fluid. and gravity pumps. displacement.  P = Power (kW) H = Water head (m) Pump A pump is a device used to move fluids. [edit] Positive displacement pump behavior and safety Positive displacement pumps. positive displacement pumps are "constant flow machines". A positive displacement pump must not be operated against a closed valve on the discharge side of the pump. unlike centrifugal or roto-dynamic pumps. because it has no shut-off head like centrifugal pumps. The volume is constant given each cycle of operation. Thus.     Rotary-type positive displacement: internal gear. The pumps can be powered by air. where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.usually simple devices for pumping small amounts of liquid or gel manually. screw. which allow liquid to slip through and reduce the efficiency of the pump. steam or through a belt drive from an engine or motor. The volume is constant given each cycle of operation. . plungers or membranes (diaphragms). Reciprocating positive displacement pumps Reciprocating pumps are those which cause the fluid to move using one or more oscillating pistons. Because of the nature of the pump. eliminating the need to bleed the air from the lines manually. the Wendelkolben pump) or liquid ring vacuum pumps. steady speed. Reciprocating-type positive displacement: piston or diaphragm pumps. the clearance between the rotating pump and the outer edge must be very close. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Typical reciprocating pumps are:    plunger pumps .g. shuttle block. Reciprocating pumps are now typically used for pumping highly viscous fluids including concrete and heavy oils. Diaphragm valves are used to pump hazardous and toxic fluids. diaphragm pumps . Reciprocating-type pumps require a system of suction and discharge valves to ensure that the fluid moves in a positive direction. they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. the fluids will cause erosion. An example is the common hand soap pump. Furthermore. Rotary pumps that experience such erosion eventually show signs of enlarged clearances. The vacuum created by the rotation of the pump captures and draws in the liquid. to in some cases "quad" four cylinders or more. Advantages: Rotary pumps are very efficient because they naturally remove air from the lines. Linear-type positive displacement: Rope pumps and chain pumps   Positive displacement rotary pumps are pumps that move fluid using the principles of rotation. requiring that the pumps rotate at a slow. Pumps in this category range from having "simplex" one cylinder. closed by suction on the way back. flexible vane or sliding vane. Liquid flows into the pumps as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. circumferential piston. helical twisted roots (e. Drawbacks: Positive displacement rotary pumps also have their weaknesses. piston displacement pumps . These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. If rotary pumps are operated at high speeds. and special applications demanding low flow rates against high resistance.similar to plunger pumps.a reciprocating plunger pushes the fluid through one or two open valves. flowing radially outward or axially into a diffuser or volute chamber. Centrifugal pumps are typically used for large discharge through smaller heads. is accelerated by the impeller and exits at right angles to the shaft (radially). . Centrifugal pumps are the most common type of pump used to move liquids through a piping system. However. Radial flow pumps operate at higher pressures and lower flow rates than axial and mixed flow pumps. axial and mixed flow variations. [edit] Radial flow pumps Often simply referred to as centrifugal pumps.Centrifugal pump A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. Centrifugal pumps are most often associated with the radial flow type. The fluid enters along the axial plane. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller. from where it exits into the downstream piping system. the term "centrifugal pump" can be used to describe all impeller type rotodynamic pumps[4] including the radial.