8-64 Steam enters a turbine at 9 MPa, 600°C, and 60 m/s and

leaves at 20 kPa and 90 m/s with a moisture content of 5 percent.

The turbine is not adequately insulated, and it estimated that

heat is lost from the turbine at a rate of 220 kW. The power

output of the turbine is 4.5 MW. Assuming the surroundings

to be at 25°C, determine (a) the reversible power output of the

turbine, (b) the exergy destroyed within the turbine, and (c)

the second-law efficiency of the turbine. (d) Also, estimate the

possible increase in the power output of the turbine if the tur-

bine were perfectly insulated.

Steam/n9 MPa

600°C, 60 m/s

Turbine

20 kPa

90 m/s

x = 0.95

FIGURE P8-64

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