A feed water pump operates with a flow rate of 350 kg/s. The water enters at 420 K. The inlet pressure is 0.7 MPa and the outlet pressure 20 MPa. Determine the power needed to drive the pump if the pump isentropic efficiency is 87%. Also determine the outlet temperature of the water. Plot the process on T-s coordinates. Show the saturated liquid line. Compressed liquid properties for water are given below. Note: Isentropic efficiency is defined differently for pumps and for turbines.
|
Pressure
(MPa)
|
Temperature
(K)
|
Specific volume
(m3/kg)
|
Enthalpy
(kJ/kg)
|
Entropy
(kJ/kg·K)
|
|
0.7 0.7 0.7
20 20 20
|
400 410 420
422.02 422.73 430
|
0.0010664 0.0010763 0.0010869
0.0010768 0.0010775 0.0010852
|
533.26 575.91 618.77
639.57 642.67 673.60
|
1.6008 1.7061 1.8094
1.8094 1.8166 1.8891
|