Chapter 7, Problem 7.78P

A steam turbine operates with an inlet condition of 30 bar, 400 0C, 160 m/s and an outlet state of a saturated vapour at 0.7 bar with a velocity of 100 m/s. The mass flow rate is 1200 kg/min and the power output is 10800 kW. present process is on T-V diagram. Determine the magnitude and direction of the heat transfer rate in kJ/min if the potential energy change is negligible.

Refrigerant 134a at 15 oC, 1.8 bar, and a mass flow rate of 5 kg/min enters an insulated compressor operating at steady state and exits at 5 bar. The isentropic compressor efficiency is 77%. Neglect the changes in kinetic and potential energies and assume the surroundings to be at 25 °C.Determine:S 1.1  the temperature of the refrigerant exiting the compressor, 1.2  the power input to the compressor, in kW, and 1.3  the rate of exergy destruction, in kW.

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.

At steady state, a device receives a stream of saturated water vapor at 210°C and discharges a condensate stream at 20°C, 0.1 MPa while delivering energy by heat transfer at 300°C. The only other energy transfer involves heat transfer at 20°C to the surroundings. Kinetic and potential energy changes are negligible. What is the maximum theoretical amount of energy, in kJ per kg of steam entering, that could be delivered at 300°C?

Carbon dioxide gas is compressed at steady state from a pressure of 1.5 bar and a temperature of 0°C to a pressure of 3.5 bar and a temperature of 40°C. The gas enters the compressor with a velocity of 9 m/s and exits with a velocity of 25 m/s. The mass flow rate is 1360 kg/hr. The magnitude of the heat transfer rate from the compressor to its surroundings is 5% of the compressor power input. Use the ideal gas model with cp = 0.88 kJ/kg K and neglect potential energy effects. a. Determine the flow area at the inlet, in m². b. Determine the compressor power, in kW. T₁=0°C P₁=1.5 bar mflow=1360kg/hr V₁-9 m/s Qout (5%) Win Win = ?? T₂-40°C P2=3.5 bar V₂-25 m/s

Water vapor flows through a two-stage turbine at steady-state, entering the inlet of the first turbine stage at a temperature of 480"C and a pressure of 10 MPa, and exiting the second turbine stage at a pressure of 0.5 bar and a quality of 95%. The mass flow rate through the first turbine stage is 15.8 kg/s, after which some of the steam is directed towards a regenerative feedwater heater. If the first turbine stage generates 8517,78 kW of work, and the second turbine stage generates 3624.2 kW of work, what is the mass flow rate (kg/s) of steam sent to the regenerative feedwater heater?

A pump operating at steady state receives 2.4 kg/s of liquid water at 50°C, 1.5 MPa. The pressure of the water at the pump exit is 15 MPa. The magnitude of the work required by the pump is 37.8 kW. Štray heat transfer and changes in kinetic and potential energy are negligible. Determine the work required by a reversible pump operating with the same conditions, in kW, and the isentropic pump efficiency.

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)

Refrigerant 22 is enters a compressor operating at steady state as saturated vapor at 10 bar and compressed adiabatically in an internally reversible process to 16 bar. Ignoring kinetic and potential energy effects, determine the required mass flow rate of refrigerant, in kg/s, if the compressor power input is 6 kW. Show this compression process on a T-s diagram.