23-08-2012, 04:06 PM
Hydroelectricity Generation
1Hydroelectricity.ppt (Size: 1.63 MB / Downloads: 110)
BASIC IDEA USED
Hydro power is a renewable resource since it is ultimately derived from sun.
The real key is the physical height difference achieved between source and sink.
Potential energy of falling water is converted into kinetic energy used to rotate turbine blades.
Turbine shaft transmits energy to electro-mechanical generators and thus hydro electricity is generated.
MULTIPLE NOZZLE PELTON TURBINE
The edge that divides each bucket in two symmetrical parts cuts the water spurt, sectioning it in two laminae of fluid, theoretically of identical volume. This disposition allows resisting mutually the axial pushes that are originated in the bun.
KAPLAN TURBINE
WORKING OF KAPLAN TURBINE
The Kaplan turbine is an inward flow water reaction turbine whose design combines radial as well as axial features.
The Kaplan turbine is a helix turbine in which the blades of the bun turn itself when it is on.
Working fluid changes pressure as it moves through the turbine.
Kaplan turbine is used for lower head applications.
FRANCIS TURBINE
1. The Francis turbine is one of the reaction turbines.
2. The radial flow causes the turn of the runner which is completely submerged in water.
3. Both the pressure and the velocity of water decrease from inlet to outlet.
4. The runner is provided with curved vanes upon which the water impinges.
5. Francis turbines is designed for a medium range of head.
ADVANTAGES OF HYDRO POWER
Technical benefits- long life span, less maintenance and no fuel cost.
Environmental benefits- renewable source, no green house gas emission
Flood migration through storage dams.
Social impact- improved standards of living, recreation spots, employment opportunity.
DISADVANTAGES OF HYDRO POWER
Disturbance to ecological system.
Adverse impact on Groundwater.
Transport of nutrients.
Population movements.
Dam breach- uncontrolled flooding.
Development of diseases due to bacteria growth in reservoir water.