Chapter 5, Problem 5.4P

6.111 Steam enters a two-stage turbine with reheat operating at steady state as shown in Fig. P6.111. The steam enters turbine 1 with a mass flow rate of 120,000 lb/h at 1000 lbf/in.², 800°F and expands to a pressure of 60 lbf/in. From there, the steam enters the reheater where it is heated at constant pressure to 350°C before entering tur- bine 2 and expanding to a final pressure of 1 lbf/in.? The turbines operate adiabatically with isentropic efficiencies of 88% and 85%, respectively. Kinetic and potential energy effects can be neglected. Determine the net power developed by the two turbines and the rate of heat transfer in the reheater, each in Btu/h. Qin P3 = 60 lbf/in.2 T = 350°C P2 = 60 lbf/in.2 Reheater W net Turbine 1 Turbine 2 Nu = 88% Ni2 = 85% P4 =1 lbf/in.2 P1 = 1000 Ibf/in.2 T = 800°F m = 120,000 lb/h FIGURE P6.111

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Weycle: The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1000°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature Tand rejects energy Qc by heat transfer to a reservoir at Tc = 450°R. All energy transfers are positive in the directions of the arrows. Hot reservoir at TH R1 W cycle Reservoir at T W cycle R2 Cold reservoir at Te Determine: (a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles. (b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1000°R and 450°R, respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Wcycle

Thermodynamics problem. Answer letter G to I only.

A power cycle operating between two reservoirs receives energy Qu by heat transfer from a hot reservoir at TH = 2000 K and rejects energy Qc by heat transfer to a cold reservoir at Tc = 400 K. For the cases below you will be asked to determine the cycle n and whether the cycle operates Reversibly, Irreversibility, or is Impossible. Сycle Сycle Сycle Assume: п — пСarnot n пСarnot 1. The maximum thermal efficiency nCarnot for the cycle is equal to а. 0.2 b. 0.8 с. 1.0 d. none of the above. 2. If QH = 1100 kJ and the Weycle = 900 kJ then the cycle is Reversible b. Irreversible c. Impossible а. d. none of the above. 3. If QH = 1000 kJ and Qc = 200 kJ then the cycle is a. Reversible b. Irreversible c. Impossible d. none of the above. 4. If Wq a. Reversible b. Irreversible c. Impossible d. none of the above. суcle 1400 kJ and Qc= 600 kJ then the cycle is 5. If n = 50% then the cycle is a. Reversible b. Irreversible c. Impossible d. none of the above.

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Wcycle. The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1500°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature T and rejects energy QC by heat transfer to a reservoir at TC = 450°R. All energy transfers are positive in the directions of the arrows.   Determine:(a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles.(b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1500°R and 450°R, respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Wcycle.

Two reversible power cycles are arranged in series. The first cycle receives energy by heat transfer from a reservoir at temperature TH and rejects energy to a reservoir at an intermediate temperature T. The second cycle receives the energy rejected by the first cycle from the reservoir at temperature T and rejects energy to a reservoir at temperature TC lower than T. Derive an expression for the intermediate temperature T in terms of TH and TC when,a. The net works of the two power cycles are equalb. The thermal efficiencies of the two power cycles are equal

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Wcycle. The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1000°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature T and rejects energy Qc by heat transfer to a reservoir at Tc = 500°R. All energy transfers are positive in the directions of the arrows. Determine: Hot reservoir at TH QH Reservoir at T R1 lo ali R2 Qc Cold reservoir at Te W. cycle W cycle (a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles. (b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1000°R and 500°R. respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Wcycle.

Solve energy balance problems for common steady-flow devices such as nozzles, compressors, turbines, throttling valves, mixing chambers, and heat exchangers.

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Weycle. The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1500°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature T and rejects energy Qc by heat transfer to a reservoir at Tc = 500°R. All energy transfers are positive in the directions of the arrows. Hot reservoir at T RI W. cycle Reservoir at T R2 Wcycle Cold reservoir at Te Determine: (a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles. (b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1500°R and 500°R, respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Woycle-