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GATE 2018 ME (ME1) – Question 34

Thermal Engineering Applications · Turbomachinery: turbines, compressors, pumps · 1 mark · Numerical answer

For a given Pelton-wheel water-jet speed, bucket-speed/jet-speed ratio for maximum output power, to two decimals, is ______.

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Show answer and explanation

Correct answer: 0.45 to 0.52

Explanation

Ideal Pelton power for fixed jet speed V is proportional to $u(V-u)$. Derivative is V − 2u, so the maximum occurs at u/V = 0.50.