Turbines

TURBINES

THE MACHINES THAT CONVERTS THE ENERGY OF THE FLUID TO MECHANICAL ENERGY

FLUID JET FROM THE NOZZLE WITH A VERY HIGH VELOCITY IMPINGES ON THE CUP OF THE BUCKET. THE CHANGE OF MOMENTUM OF THE JET PRODUCES A THIRST ON THE BUCKET AS A RESULT OF WHICH THE WHEEL THAT CARRIES THE BUCKET FIXED ON ITS PERIPHERY RECEIVES A TORQUE AND STARTS TO ROTATE AND THUS PRODUCES ROTATIONAL KINETIC ENERGY.

PREPARED By SUBHANKAR KARMAKAR

Schematic diagrams of a generalized fluid machine

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The impulse turbine has one or more fixed nozzles. The nozzles turn the pressure energy into kinetic energy as high velocity jets of fluid. These jets then impinge on the moving blades of the runner where the fluid loses almost all of its kinetic energy and the momentum is transferred to the blade. A typical impulse turbine is the pelton wheel. The reaction turbine fluid transfers its energy by tangential slippage across the blades literally pushing the blades sideways out of its path. The energy transfer is a gradual process, the fluid loses it kinetic energy progressively. The fluid literally fills all of the passages through turbine blades. A typical reaction turbine is the steam or gas turbine.

TURBINES ARE OF TWO TYPES

(i) REACTION TURBINES (ii) IMPULSE TURBINES

REACTION TURBINES : FRANCIS TURBINES The reaction turbine is completely immersed in the fluid and the energy is converted from fluid to mechanical motion , and vice versa, gradually as the fluid passes over the blades

IMPULSE TURBINES :

PELTON WHEEL : AN IMPULSE TURBINE

VELOCITY DIAGRAMS

The impulse turbine has one or more fixed nozzles. The nozzles turn the pressure energy into kinetic energy as high velocity jets of fluid. These jets then impinge on the moving blades of the runner where the fluid loses almost all of its kinetic energy and the momentum is transferred to the blade. A typical impulse turbine is the pelton wheel

EXAMPLE OF TURBINES SPRINKLER: A REACTION TURBINE

PADDLE WHEEL: AN IMPULSE TURBINE