Pelton Wheel — Recommended Bucket Depth For a Pelton wheel, the typical depth of a bucket is approximately how many times the jet diameter?
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Aequal to
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B1.2 times
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C1.8 times
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Ddouble
Answer
Correct Answer: 1.2 times
Explanation
Introduction:Geometric proportions of Pelton buckets (width, depth, splitter dimensions) are standardized to capture and deflect the jet effectively while minimizing losses and avoiding jet interference.
Given Data / Assumptions:
- Impulse turbine with free jet striking double-cupped buckets.
- Design guidance from classical proportions used in practice.
Concept / Approach:Bucket depth affects jet containment and deflection angle. Too shallow causes spillage; too deep increases friction and weight. Empirical design ratios recommend bucket depth about 1.2 * d, where d is jet diameter, balancing capture and hydraulic efficiency.
Step-by-Step Solution:Choose bucket dimensions based on jet size.Adopt depth ≈ 1.2 * d to house the jet adequately.Verify clearance to avoid interference with adjacent buckets.
Verification / Alternative check:Reference proportion sets also suggest bucket width ≈ 5 * d and pitch ≈ 2.3 * d, consistent with the chosen depth.
Why Other Options Are Wrong:equal to: marginal capture; prone to spillage.1.8 times and double: unnecessarily deep, increasing losses and mass.
Common Pitfalls:Using nonstandard ratios that degrade hydraulic efficiency.
Final Answer:1.2 times