Solve this multiple-choice question and choose the correct option.

Home » Mechanical Engineering » Steam Nozzles and Turbines

Driving force in an impulse–reaction turbine For an impulse–reaction turbine stage, identify the nature of the driving force acting on the moving blades. Choose the correct option.

Difficulty: Easy

An impulsive force only
A reaction force only
Partly impulsive and partly reaction
None of the above

Correct Answer: Partly impulsive and partly reaction

Explanation:

ConceptIn an impulse–reaction stage, part of the pressure drop occurs in the fixed nozzles (impulse component) and part within the moving blades (reaction component). The resulting torque arises from both the change in jet momentum (impulse) and from pressure forces across the rotor passages (reaction).

Final AnswerPartly impulsive and partly reaction

← Previous Question Next Question→

More Questions from Steam Nozzles and Turbines

Supersaturated steam flow through a nozzle vs. stable (equilibrium) flow When steam expands with supersaturation (delayed condensation), how does the available heat drop compare to a stable (equilibrium) expansion? Choose the correct option.
Applications of steam turbines Identify where steam turbines are commonly used in practice. Choose the correct option.
Type classification: De Laval turbine Classify the De Laval turbine according to type and staging. Choose the correct option.
Exit state from a nozzle Steam leaves a nozzle with what typical combination of pressure and velocity? Choose the correct option.
Parsons turbine: impulse or reaction? Identify the correct classification of a Parsons turbine stage. Choose the correct option.
Choked flow in a convergent–divergent steam nozzle Statement: In a C–D nozzle, the mass discharge rate depends on the initial (inlet) steam conditions and the throat area (once choked), not on the exit pressure. Decide whether the statement is correct.
Effect of reducing back (exit) pressure on nozzle mass flow As the exit/back pressure is gradually reduced from high to low values, how does the mass discharge rate through a steam nozzle change? Choose the correct option.
Steam nozzle back pressure vs design exit pressure: identify the nozzle condition for expansion. Given: Back pressure (ambient) is lower than the designed exit pressure of the nozzle. Choose the correct technical term that describes the nozzle condition.
Definition check: What qualifies as a convergent nozzle in fluid/steam-nozzle terminology? Identify the correct description of how the cross-sectional area changes from inlet to exit. Choose the correct option.
True/False (steam nozzles): Compare critical pressure ratios for different steam qualities. Statement: “The critical pressure ratio for initially dry saturated steam is greater than that for initially wet steam.” Decide whether the statement is correct.

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion