PRESENTATION ON HYDRO TURBINES

HYDRO TURBINE

Hydro turbine converts energy of water into mechanical energy and further into electrical energy by generator. Hydro turbines are classified on the basis of action of water on moving blades.

CLASSIFICATION OF HYDRO TURBINES As per the action of water on moving

blades, hydro turbines are classified as:

Impulse turbineReaction turbine

IMPULSE TURBINE

In impulse turbine, the pressure energy of water when passed through nozzle is converted into kinetic energy and forms the high velocity jet of water. The formed jet is used to drive the wheel. The casing of impulse turbine operates under atmospheric pressure. Impulse turbine requires high head and small quantity of flow.

PELTON TURBINE

Pelton turbine is generally mounted on horizontal shaft. A number of buckets are mounted round the periphery. Water is directed through nozzle towards buckets. The flow of water through nozzle is controlled by special regulating system. For max speed of rotation, the mean diameter of runner should be small.

TURGO TURBINE

In turgo impulse turbine, a much larger jet can be applied to runner of a given diameter. With turgo impulse turbine, the jet is set at an angle to face the runner, strikes the buckets at the front and discharges at opposite side.

PELTON/TURGO TURBINE

Rated head is 80-1600m

Rated flow is 0.1-20m3/s

Rated speed is 150-1500rpm

Rated o/p is 100KW-80MW

REACTION TURBINE

The power in reaction turbine is developed from the combined action of pressure and velocity of water. The casing of reaction turbine operates unde high pressure. The casing of reaction turbine is made completely leakproof.

FRANCIS TURBINE

In francis turbine, the water enters into a casing with a relatively low velocity, passes through guide vanes located around the cicumference and flows through runner and finally discharged into draft tube. The water passage from headrace to tailrace is completely filled with water.

FRANCIS TURBINE

Rated head is10-300m

Rated flow is 0.3-100m3/s

Rated speed is 68.2-1500rpm

Rated o/p is 100KW-100MW

Francis turbine

PROPELLER TURBINE

Propeller turbine can be considered as development of a Francis turbine. The only disadvantage of Francis turbine is that the runner blades are fixed and nonadjustable. But in case of propeller turbine blades are adjusted automatically by servomechanism. Movable blades type propeller turbine is known as Kaplan turbine.

KAPLAN TURBINE

Kaplan turbine is a propeller turbine having movable blades instead of fixed one. The blades of turbine are rotated to most efficient angle by a hydraulic servo motor. These turbines are suitable for variable heads and variable flows where ample quantity of water is available.

KAPLAN TURBINE

Rated head is 2-70m

Rated flow is 1-200m3/s

Rated speed is 68.2-750rpm

Rated o/p is 100KW-100MW

OPTIMUM HYDROELECTRIC TURBINE TYPE

EFFICIENCIES OF TURBINES

Hydraulic efficiency: It is the ratio of power developed by the runner of turbine to the power supplied by the water at the inlet of turbine.

Mechanical Efficiency: It is the ratio of power availabe at the shaft of turbine to the power developed by runner.

Volumetric Efficiency: It is the ratio of volume of water actually striking the runner to the volume of water supplied to the turbine.

Overall Efficiency: It is the ratio of power available at the shaft to the power supplied by water at inlet of water.

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