Question
A single jet Pelton wheel operates at 300 rpm. The mean diameter of the wheel is 2 m. Operating head and dimensions of jet are such that water comes out of the jet with a velocity of 40 m/s and flow rate of 5 m³ /s. The jet is deflected by the bucket at an angle of 165°. Neglecting all losses, the power developed by the Pelton wheel is ______________ MW (round off to two decimal places).
Answer :
Correct answer is : 2.65
N = 300 rpm, D = 2 m,δ = 165°, V1 = 40 m/s, Q = 5 m3/s
Angle of deflection (δ) = 180° - ϕ
∴ ϕ = 180° - 165° ⇒ 15°
Power developed = ρQ(V1 - u)[1 + cos ϕ]u
∴ Power developed = 103 × 5 × (40 - 31.415) × (1 + cos 15°) × 31.415
∴ Power developed = 2.65 MW
The power developed by the Pelton wheel is 2.65 MW.
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