Which of these statements about an impulse turbine are correct or incorrect?
I. The pressure remains constant across the nozzle guide vanes
II. The pressure drops across the rotor blades
Refer to figure.
IMPULSE TURBINE | ||
Nozzle guide vanes (form convergent ducts – accelerate the gas) | Velocity increases | Pressure decreases |
Rotor Blades | Velocity decreases | No change in pressure |
REACTION TURBINE | ||
Nozzle guide vanes | Pressure remains constant | |
Rotor Blades (form convergent ducts – accelerate the gas, creating reaction force which drives the turbine) | Velocity increases | Both temperature and pressure decrease |
According to Rolls Royce, in a reaction turbine, the nozzle guide vanes simply direct the gas onto the turbine blades. Therefore, there is no change in speed or pressure across them, only a change in direction.
Correct option: INCORRECT, INCORRECT
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