Chapter 8, Problem 8.22P

1.) A steam power plant uses the ideal Reheat Rankine cycle where the steam enters the high-pressure turbine at 4 MPa and 300C. It partially expands to 600 kPa then it is reheated to the same temperature. After expanding again, it enters the condenser at 10 kPa. Sketch the schematic diagram and the TS diagram with labeled points, and solve for Qa, Qr, Wt, Wp, Wnet, thermal efficiency, and Steam rate kg 3241.70,2144.67,1101.06 4.03, 1097.03 33.84%, 3.28 k kJ kg kl, kg kWh

In a reheat cycle steam at 15 MPa, 540°C enters the engine and expands to 1.95 MPa. At this point the steam is withdrawn and passed through a reheater. It reenters the engine at 540°C. Expansion now occurs to the condenser pressure of 0.0035 MPa. (a) For the ideal cycle, find e. (b) A 60,000 kw turbine operates between the same state points except that the steam enters the reheater at 1.95 MPa and 260°C, departs at 1.8 MPa and 540°C. The steam flow is 147,000 kg/hr, generator efficiency is 96%. For actual engine, finde, m,, and m, (c) Determine the approximate enthalpy of the exhaust steam if the heat lost through the turbine casing is 2% of the combined work. Ans.: (a) 46.1%, (b) 37.3%, 2.45 kg/kwh, 79.3%, (c) 2489.6 kJ/kg

In a reheat cycle steam at 15 Mpa, 540°C enters the engine and expands to 1.95 Mpa. At this point the steam is withdrawn and passed through a reheater. It reenters the engine at 540°C. Expansion now occurs to the condenser pressure of 0.0035 Mpa. (a) For the ideal cycle, find ee (b) A 60,000 kW turbine operates between the same state points except that the steam enters the reheater at 1.95Mpa and 260°C, departs at 1.8 Mpa and 540°C. The steam flow is 147,000 kg/hr; generator efficiency is 96%. For actual engine, ek, mk, and nk, (c) Determine the approximate enthalpy of the exhaust steam if the heat lost through the turbine casing is 2% of the combined work.4. Steam at 200 bar, 760°C enters the thrott

A steam power plant operating on a simple ideal Rankine cycle maintains the boiler at 6000 kPa, turbine inlet at 600°C, and condenser at 50 kPa. Calculate and Compare the thermal efficiency of this cycle when a) It is operated in such a way that the liquid enters the pump as saturated liquid at the pressure of the pump. condenser. b) It is operated in such a way that the liquid enters the pump 11.3 °C colder than a saturated liquid. at condenser pressure. c) Plot the process from a) on a T-s diagram.

1. In an ideal reheat-regenerative cycle, steam enters the turbine at 6 MPaa and 400°C. After expansion to 1.4 MPaa steam is withdrawn and reheated to 300°C. Extractions for regenerative heating occur at 0.15 MPaa and 1.4 MPaa and the condenser pressure is 0.01MPaa. Use mass flowrate of 1 kg/s. (total=60 points) a. Sketch the schametic diagram showing the correct state points and its components. (5 points)

Water is the working fluid in a Rankine cycle with reheat. 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 and then is reheated to 480°C. The pump and each turbine stage have an isentropic efficiency of 70%.Determine for the cycle:(a) the total heat addition, in kJ per kg of steam entering the turbine.(b) the percent thermal efficiency.(c) the magnitude of 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.

a. Calculate the thermal efficiency and turbine-exit quality for an Ideal Rankine Cycle where the steam exits boiler at 5MPa, 450C and the condenser pressure is 15 kPa. Draw the systems and the Ts diagram for the process. b. Calculate also the thermal efficiency and turbine-exit quality if the system is modified to an Ideal Reheat Rankine Cycle where the reheat takes place at 1 MPa and the steam leaves the reheater at 500C. Draw the systems and the Ts diagram for the process and discuss your findings of these two systems.

Thermodynamics

1. In a reheat cycle steam at 15 MPa, 500oC enters the engine and expands to 2 MPa. At this point the steam is withdrawn and passed through a reheater. It reenters the engine at 500oC. Expansion now occurs to the condenser pressure of 5 kPa. The steam flow is 150000 kg/hr, the generator efficiency is 96%, mechanicalefficiency of 80% and indicated steam rate of 5.5 kg/kWh. For actual engine, find the following:a. output power in kWb. brake steam ratec. brake thermal efficiencyd. combined engine efficiency 2. An ideal reheat Rankine cycle operates between 8 MPa and 5 kPa with a maximum temperature of 600oC. Two reheat stages, each with a maximum temperature of 600oC are to be added to 2 MPa and 100 kPa. Calculate:a. turbine workb. heat added in the boilerc. heat added in the reheaterd. thermal efficiency