Question

A pelton turbine is to operate under a net head of 650 m at 480 rpm. If a single jet with diameter 18 cm is used, then the specific speed of the machine is (Cv = 0.98, overall efficiency = 85%
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Answer 1

Explanation:

[tex]A pipe 300 m long with a diameter of Dp=15 cm and a friction coefficient λ=0.02 supplies water from a

reservoir situated 150 m above see level to a Pelton nozzle situated 90 m above see level. Assuming the losses

in the nozzle of the form 0.04 V2

/(2g), determine the jet diameter Dj, which gives maximal effect. Inlet losses

from the reservoir to the pipe are neglected.

Answer:

1/ 4 1 5

2

D D j L

ξ

λ

⎛ + = ⎜

⎝ ⎠ P

⎞

⎟ , Dj=5 cm[/tex]