Question

# A steam turbine has inlet steam pressure p1 = 1.4 MPa absolute. Inlet steam temperature is...

A steam turbine has inlet steam pressure p1 = 1.4 MPa absolute. Inlet steam temperature is T1 = 400 oC. This corresponds to inlet enthalpy per unit mass of h1 = 3121 kJ/kg. Exit pressure of the steam is p2 = 101 kPa absolute. Exit steam temperature is T2 = 100 oC. This corresponds to exit enthalpy per unit mass of h2 = 2676 kJ/kg. Inlet speed of the steam is V1 = 15 m/s and exit speed is V2 = 60 m/s. Axis of the steam turbine is horizontal. Time-rate of heat loss through the walls of the turbine is Q = 7600 kJ/h. The mass flow rate of steam through the turbine is 0.5 kg/s.

a) If the power extracted by the turbine is Pactual = 200 kW, what is the amount of power loss (expressed in kW) due to viscous effects?

b) If there would be no viscous losses, what would be the ideal power, Pideal, extracted by the turbine (in kW)?

c) What is the coefficient of efficiency, ?, of the turbine?

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