Impulse turbine energy exchange: Jet velocity at entry and exit Evaluate the statement: In an impulse turbine, water 'impinges with a low velocity and leaves with a high velocity' after flowing over the buckets. Choose the correct judgment.
Mechanical Engineering
Hydraulic Machines
Difficulty: Easy
Choose an option
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ATrue — entry velocity is lower; exit velocity is higher
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BFalse — entry velocity is high; exit velocity is reduced after energy transfer
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CTrue only for multi-jet Pelton wheels
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DTrue only under part-load conditions
Answer
Correct Answer: False — entry velocity is high; exit velocity is reduced after energy transfer
Explanation
Concept/Approach
- Impulse turbines (e.g., Pelton) convert the entire available head into jet kinetic energy before the runner.
ReasoningThus, the jet strikes the buckets at high velocity and ideally leaves with a much lower absolute velocity after transferring energy to the runner.
Final AnswerFalse — the jet arrives fast and leaves slower.