Chapter 8, Problem 8.25P

Water is used as the working fluid in an ideal Rankine Cycle. Steam enters the turbine at a pressure and temperature of 30 MPa and 620 deg C, respectively. The condenser pressure is 100 kPa. Determine the cycle thermal efficiency.

In a steam power plant operating according to the ideal Rankine cycle at 4MPa pressure and 400CIt enters and condenses in the condenser at a pressure of 100kPa. Determine the efficiency of the cycle.What would the efficiency be if the steam entered the turbine at 5MPa pressure and condensed at 90kPa pressure.

An ideal reheat Rankine cycle with water as the working fluid operates the inlet of the high-pressure turbine at 7000 kPa and 450°C, the inlet of the low-pressure turbine at 500 kPa and 500°C, and the condenser at 10 kPa. Determine the mass flow rate through the boiler needed for this system to produce a net 5000 kW of power and the thermal efficiency of the cycle. Use steam tables. kg/s. The mass flow rate through the boiler needed for this system to produce a net 5000 kW of power is The thermal efficiency is %.

An ideal Reheat-Regenerative engine operates with a boiler pressure of 8 MPa and a condenser pressure of 8 kPa. Throttle steam at 8 MPa, 480°C is expanded in the turbine to 2 MPa where it is withdrawn from the turbine and reheated to 460°C. The reheated steam then expands in the turbine to 300 kPa where a portion of the steam is extracted for feedwater heating in an open heater. The remainder of the steam continues its expansion to the condenser pressure of 8 kPa. Removing the reheater while retaining the feedwater heater,  what is the: % of mass extracted? turbine work in kJ/kg? thermal efficiency?  energy chargeable against the engine in kJ/kg?

An ideal Reheat-Regenerative engine operates with a boiler pressure of 8 MPa and a condenser pressure of 8 kPa. Throttle steam at 8 MPa, 480°C is expanded in the turbine to 2 MPa where it is withdrawn from the turbine and reheated to 460°C. The reheated steam then expands in the turbine to 300 kPa where a portion of the steam is extracted for feedwater heating in an open heater. The remainder of the steam continues its expansion to the condenser pressure of 8 kPa. What is the: turbine Work in kJ/kg? % of mass extracted for feedwater heating? thermal efficiency? energy chargeable against the engine in kJ/kg?

Calculate the work done in the low-pressure turbine (LPT) of a Rankine cycle with reheat. The steam enters the LPT at 425°C & 60 MPa and leaves LPT as superheated steam at 375°C & 50MPA. Suggest what would be the dryness fraction of the working fluid entering the condenser.

8.25 Water is the working fluid in an ideal regenerative Rankine cycle. Superheated vapor enters the turbine at 10 MPa, 480°C, and the condenser pressure is 6 kPa. Steam expands through the first-stage turbine to 0.7 MPa where some of the steam is extracted and diverted to an open feedwater heater operating at 0.7 MPa. The remaining steam expands through the second-stage turbine to the condenser pressure of 6 kPa. Saturated liquid exits the feedwater heater at 0.7 MPa. Determine for the cycle a. the heat addition, in kJ per kg of steam entering the first-stage turbine. 2613.9 b. the thermal efficiency. 44.2% c. the heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam entering the first-stage turbine. 1458.4

An ideal reheat Rankine cycle with water as the working fluid operates the boiler at 15,000 kPa, the reheater at 2000 kPa, and the condenser at 100 kPa. The temperature is 450C at the entrance of the high-pressure and lowpressure turbines. The mass flow rate through the cycle is 1.74 kg/s. Determine the power used by pumps, the power produced by the cycle, the rate of heat transfer in the reheater, and the thermal efficiency of this system.

An ideal reheat cycle has steam enters the high pressure turbine at 780psia and 860°F and leaves at 90psia. It is then reheated to 840°F, passes through the low pressure turbine and exhausts to a condenser at 3psia. What is the thermal efficiency of the cycle?