Impulse turbines

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Impulse turbines

  1. 1. 2012Impulse Turbines Mo’tasem Abushanap TUTO 11/4/2012
  2. 2. 4/11/2012 Mo`tasem Ash Impulse Turbines Definition In an impulse turbine the runner operates in air, and is turned by one or multiple jets of water which make contract with the blade. A nozzle converts the pressurized low velocity water into a high speed jet much like you might use with a garden hose nozzle. The nozzle is aligned so that it provides maximum force on the blades; they can be used for medium and high heads. Examples of this type are: a- Pelton Wheel: it is suitable for high heads and low flows, best operating heads 15- 1800m, it can generate up to 200 MW. b- Turgo: it is a modification of Pelton wheel where the runner is a cast wheel whose shape generally resembles a fan blade that is closed on the outer edges. The water stream is applied on one side, goes across the blades and exits on the other side, it used for medium heads, its head range 15-30m. c- Jonval Wheel: in which water descends through fixed curved guide vanes which direct the flow sideways onto curved vanes on the runner d- Water wheel: a machine for converting the energy of free-flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface. Most commonly, the wheel is mounted vertically on a horizontal axle, but the tub or Norse wheel is mounted horizontally on a vertical shaft. Vertical wheels can transmit power either through the axle or via a ring gear and typically drive belts or gears; horizontal wheels usually directly drive their load. Impulse Turbines Pelton Wheel Whater Jonval Turgo Wheel Figure 1.1 Impulse Turbines http://www.scribd.com/motasem_ash , Mo`tasem Abushanap 20121
  3. 3. 4/11/2012 Mo`tasem Ash Figure 1.3 Impulse Turbines Calculation of Pelton Wheel ηs=√ …………………………………………………………………1 P.E=m.g.h………………………………………………………………….2 K.E= m.V2…………………………………………………………………3 Vi=√ ………………………………………………………….……….4  Assume that al velocity vectors are parallel to each other.  Define speed of the runner as (u). Vi-u = initial velocity relative to runner speed. Vf=(-Vi+u)+u= -Vi+2u……………………………………………….……5 If Vf=0, then we have Ideal speed http://www.scribd.com/motasem_ash , Mo`tasem Abushanap 20122
  4. 4. 4/11/2012 Mo`tasem Ash u=Vi/2…………………………………………………………….……….6 which means that all the kinetic energy in the jet is transferred to the wheel. By applying newton’s 2nd and 3rd laws F = -m(Vf-Vi) = -ρQ[(-Vi+2u)-Vi] = -ρQ(-2Vi+2u) =2ρQ(Vi-u)……………………..……………………………….……….7 T= F(D/2) =ρQD(Vi-u)……………………………………………………..………..8 P=ω.T =F.u =2ρQ(Vi-u)*u………………………………………………….…………9 Assume Vf=0, Pmax= ρQVi2/2 Pmax= ρgHQ…………………………………………………..………….10 η= 4u(Vi-u)/Vi……………………………………………….…..………11 References 1. http://en.wikipedia.org/wiki/Hydraulics 2. http://www.turbinesinfo.com/what-is-a-turbine/ 3. http://www.wisegeek.com/what-is-a-turbine.htm 4. http://www.thermopedia.com/content/859/ 5. http://en.wikipedia.org/wiki/Turbine#Types 6. http://hassam.hubpages.com/hub/Types-Of-Turbines 7. http://www.ehow.com/list_7453448_types-hydraulic-turbines.html 8. http://www.energybible.com/water_energy/water_turbines.html 9. http://en.wikipedia.org/wiki/Pelton_wheel 10. http://www.frenchriverland.com/pelton_wheel.htm 11. http://www.microhydropower.com/our-products/pelton-wheel/ 12. http://en.wikipedia.org/wiki/Turgo_turbine 13. http://www1.eere.energy.gov/water/hydro_turbine_types.html http://www.scribd.com/motasem_ash , Mo`tasem Abushanap 20123
  5. 5. 4/11/2012 Mo`tasem Ash 14. http://en.wikipedia.org/wiki/Jonval_turbine 15. http://en.wikipedia.org/wiki/Water_wheel 16. https://d2t1xqejof9utc.cloudfront.net/screenshots/pics/ebbc86d5d057cef74fb3c8d59d697 9e3/medium.jpg 17. http://www.hydrogenappliances.com/pelton_wheel_diagram.gif 18. http://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Turgo_turbine.png/220px- Turgo_turbine.png 19. http://upload.wikimedia.org/wikipedia/commons/3/3f/Waterwheel_2.png 20. http://upload.wikimedia.org/wikipedia/commons/thumb/5/53/Overshot_water_wheel_sch ematic.svg/220px-Overshot_water_wheel_schematic.svg.png 21. http://www.british-hydro.org/mini-hydro/images/turgo-sketch.gif 22. http://upload.wikimedia.org/wikipedia/commons/thumb/7/7c/Schiffbau_jonval2.jpg/200p x-Schiffbau_jonval2.jpg 23. http://www.pioneer-sys.net/images/microhydro/micro_7.gif 24. http://www.pumpfundamentals.com/micro-hydro.htm http://www.scribd.com/motasem_ash , Mo`tasem Abushanap 20124

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