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Reaction turbines: source of axial thrust Given causes: (a) Pressure drop across the rotor (b) Change in axial component of velocity Select the correct cause(s) of axial thrust.

Difficulty: Easy

Pressure drop across the rotor only
Change in axial velocity only
Both (a) and (b)
None of these

Correct Answer: Both (a) and (b)

Explanation:

Concept/Approach

In a reaction turbine, static pressure drops across both stator and rotor; a net pressure force acts on rotor disks in the axial direction.
Additionally, a change in axial momentum (axial velocity component) across the rotor produces axial thrust.

Final Answer
Both (a) and (b)

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