Question

Electric power is to be generated by installing a hydraulic turbine–generator at a site 110 m below the free surface of a large water reservoir that can supply water steadily at a rate of 900 kg/s. If the mechanical power output of the turbine is 800 kW and the electric power generation is 750 kW, determine the turbine efficiency and the combined turbine–generator efficiency of this plant. Neglect losses in the pipes.

Answer 1

Answer:

Given that

h = 110 m

Mass flow rate(m') = 900 kg/s

Mechanical power = 800 KW

Power generation = 750 KW

p = m' g h

P= 900 x 10 x 110

P= 990 KW

The turbine efficiency ηt

ηt = 800 /990

ηt = 0.808

Generator efficiency ηg

ηg= 750/800

ηg= 0.93

Combine efficiency η

η = ηt  x ηg

η =0.75