Superheated steam at 20 mpa, 560c enters the turbine of a vapor power plant. the pressure at the exit of the turbine is 0.5 bar, and liquid leaves the condenser at 0.4 bar at 75 degrees c. the pressure is increased to 20.1 mpa across the pump. the turbine and pump have isentropic efficiencies of 81 and 85%, respectively. cooling water enters the condenser at 20 degreesc with a mass flow rate of 70.7 kg/s and exits the condenser at 38 degreesc. for the cycle, determine

(a) the mass flow rate of steam, in kg/s.
(b) the thermal efficiency

Heat is added to a piston-cylinder device filled with 2 kg of air to raise its temperature 400 c from an initial temperature of t1 27 cand pressure of pi 1 mpa. the process is isobaric process. find a)-the final pressure p2 b)-the heat transfer to the air.

Fluids at rest possess no flow energy. a)- true b)- false

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?