Chapter 6, Problem 6.89P

Water at p1 = 20 bar, T1 = 400oC enters a turbine operating at steady state and exits at p2 = 1.5 bar, T2 = 180oC.  The water mass flow rate is 4000 kg/hour. Stray heat transfer and kinetic and potential energy effects are negligible. Determine the power produced by the turbine, in kW, and the rate of entropy production in the turbine, in kW/K.

Water at p1 = 20 bar, T1 = 400oC enters a turbine operating at steady state and exits at p2 = 1.5 bar, T2 = 200oC.  The water mass flow rate is 4000 kg/hour. Stray heat transfer and kinetic and potential energy effects are negligible.Determine the power produced by the turbine, in kW, and the rate of entropy production in the turbine, in kW/K.

Refrigerant 134a at p1 = 30 lbf/in2, T1 = 40oF enters a compressor operating at steady state with a mass flow rate of 350 lb/h and exits as saturated vapor at p2 = 160 lbf/in2. Heat transfer occurs from the compressor to its surroundings, which are at T0 = 40oF. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 3.5 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr·oR.

Refrigerant 134a enters an insulated diffuser as a saturated vapor at 60oF with a velocity of 1000 ft/s. The inlet area is 1.4 in2. At the exit, the pressure is 400 lbf/in2 and the velocity is negligible. The diffuser operates at steady state and potential energy effects can be neglected.Determine the mass flow rate, in lb/s, and the exit temperature, in oF.

Refrigerant 134a enters an insulated diffuser as a saturated vapor at 80 deg F with a velocity of 800 ft/s. The inlet area is 1.4 in^2. At the exit, the pressure is 400 lbf/in2 and the velocity is negligible. The diffuser operates at steady state and potential energy effects can be neglected. Determine the mass flow rate, in lb/s, and the exit temperature, in deg F.

Water vapor enters a turbine operating at steady state at 1000oF, 230 lbf/in2, with a volumetric flow rate of 25 ft3/s, and expands reversibly and adiabatically to 2 lbf/in2. Ignore kinetic and potential energy effects.    determine the mass flow rate in lb/s and  the power developed by the turbine in hp.

Steam enters a well-insulated turbine operating at steady state with negligible velocity at 4 MPa, 320°C. The steam expands to an exit pressure of 0.07 MPa and a velocity of 90 m/s. The diameter of the exit is 0.6 m. Neglecting potential energy effects, plot the power developed by the turbine, in kW, versus the steam quality at the turbine exit ranging from 0.9 to 1.0.

In a thermal power plant, an adiabatic steam turbine operating at steady state with inlet conditions at pressure of 30 bar, temperature of 350°C and mass flow rate of 10 kg/s. Half of the steam is extracted at the first exit at pressure of 5 bar and temperature of 200°C. The remaining steam leaves the second exit at pressure of 0.15 bar and a quality of 0.9. Neglect the change in kinetic and potential energy and the surroundings is assumed to be a temperature of 25°C and atmospheric pressure. Determine: a) The total work produced by the turbine (in kW) b) The exergy destruction (in kW) c) The second law efficiency of the turbine d) It is proposed to modify the turbine blade in order to increase the performance of the steam turbine. With this modification, the steam conditions at the inlet and the first exit remain the same but the steam will leave the second exit at pressure of 0.1 bar and a quality of 0.9. Perform an appropriate analysis and justify whether it is worth considering…

3. Water enters a turbine operating at steady state with an initial state of Pi=40 bar and T1= 520°C and exits at P2= 0.1 bar. When provided with a mass flow rate of 3 kg/s, the turbine is able to develop 2.3 MW of power. Heat transfer to the environment and changes in kinetic/potential energy can be neglected. Determine the following: a. the isentropic efficiency, ni (%) b. the rate of entropy production per kg of steam (kJ/kg-K)