Chapter 8, Problem 8.121EP

Q4 a- The pressure inlet for air compressor is 14 psi ,60 F and the output of 140 psi at 1080 R .This output passes through a cooler of constant pressure .if the exit air out of cooler is 540R find the specific work and specific heat of this compressor .use the table below in case.

· A closed gaseous system undergoes a reversible process with constant pressure of 200kpa. 2500 kJ of heat is rejected, and the volume changes from 5m3 to 2m3. Find the change in internal energy

An amount of 4000 BTU of heat is transferred from a reservoir at 800 deg. F to a reservoir at 200 deg. F. Find the entropy change of the system.

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Steam to a turbine at a mass flow rate of 1.4 kg/s, 700 kPa pressure and 400 °C enters the temperature. Steam at 100 kPa pressure and 1.4 m3/kg specific volume exits the turbine. Heat transfer from turbine to environment 50 kW, with turbine Since the boundary temperature between the environment is 70 °C, a) Find the power produced by the turbine, entropy produced in the turbine and isentropic efficiency of the turbine. Note: The changes in kinetic and potential energies will be neglected and T (K) = 273 + °C will be taken.

2. A closed constant volume system receives 10.5 kJ of paddle work. The system contains oxygen at 344 kPa, 278 K and occupies 0.06 cu. m. Find the heat (gain or loss) if the final temperature is 400 K.

A refrigeration system has a heat added of 440 kw. If COP is 7,find the mass of cooling water in the condenser for a temperature increase of 14°C.

A mixing chamber with heat transfer receives 2 kg / s of R - 134a at 1 MPa, 50 ° C in one line and 1 kg / s of R - 134a at 15 ° C, quality 40% in a line with a valve. The outgoing Now is at 1 MPa, 70 ° C Find the rate of heat transfer to the mixing chamber

The turbine section in a jet engine receives gas (assume air) at 1200 K, 800 kPa with an ambient atmosphere at 80 kPa. The turbine is followed by a nozzle open to the atmosphere and all the turbine work drives a compressor receiving air at 85 kPa, 270 K with the same flow rate. Find the turbine exit pressure P₂ so the nozzle has an exit velocity of 800 m/s.