Question

Tutorial Questions 1

.1. Water is the working fluid in an ideal Rankine cycle. The condenser pressure is kPa, and saturated vapor enters the turbine at 10 MPa. Determine the heat transfer rates, in kJ per kg of steam flowing, for the working fluid passing through the boiler and condenser and calculate the thermal efficiency.

2. Water is the working fluid in an ideal Rankine cycle. Saturated vapor enters the turbine at 16 MPa, and the condenser pressure is 8 kPa . The mass flow rate of steam entering the turbine is 120kg/s. Determine

(a) the net power developed, in kW. (b) the rate of heat transfer to the steam passing through the boiler, in kW. (c) the thermal efficiency. (d) the mass flow rate of condenser cooling water, in kg/s, if the cooling water undergoes a temperature increase of 18℃ with negligible pressure change in passing through the Condenser.

3. Water is the working fluid in a Carnot vapor power cycle. Saturated liquid enters the boiler at 16MPa, and saturated vapor enters the turbine. The condenser pressure is 8 kPa. The mass flow rate of steam entering the turbine is 120kg/s. Determine (a) the thermal efficiency. (b) the back work ratio. (c) the net power developed, in kW. (d) the rate of heat transfer from the working fluid passing

through the condenser, in kW.

4. A power plant based on the Rankine cycle is under development to provide a net power output of 10 MW. Solar collectors are to be used to generate Refrigerant 22 vapor at 1.6MPa, 50℃, for expansion through the turbine. Cooling water is available at 20℃. Specify the preliminary design of the cycle and estimate the thermal efficiency and the refrigerant and cooling water flow rates, in kg/h.

5. Water is the working fluid in a Rankine cycle.

Superheated vapor enters the turbine at 10MPa, 480℃, and the condenser pressure is 6kPa. The turbine and pump have isentropic efficiencies of 80 and 70%, respectively. Determine for the cycle (a) the rate of heat transfer to the working fluid passing through the steam generator, in kJ per kg of steam flowing. (b) the thermal efficiency. (c) the rate of heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam flowing.

6. Steam at 10 MPa, 600℃ enters the first-stage turbine of an ideal Rankine cycle with reheat. The steam leaving the reheat section of the steam generator is at 500℃, and the condenser pressure is 6 kPa. If the quality at the exit of the second-stage turbine is 90 %, determine the cycle thermal efficiency.

7. Water is the working fluid in an ideal Rankine cycle with reheat. Superheated vapor enters the turbine at 10 MPa, 480℃, and the condenser pressure is 6 kPa. Steam expands through the first-stage turbine to 0.7 MPa and then is reheated to 480℃. Determine for the cycle (a) the rate of heat addition, in kJ per kg of steam entering the first-stage turbine. (b) the thermal efficiency. (c) the rate of heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam entering the firststage turbine.

8. Water is the working fluid in an ideal regenerative Rankine cycle. Superheated vapor enters the turbine at 10 MPa, 480℃, 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 rate of heat addition, in kJ per kg of steam entering the first-stage turbine. (b) the thermal efficiency. (c) the rate of heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam entering the firststage turbine.

Answer 1

Solutim:-0 A Condenges ressure-f GK from SteaM table At R- 10MPA - > he 2725 4?3 KJ k KJ At tf 6k00L MPa heF 151-434 K1g Ste os21 KS3K 3.329 SSy 5.l60S21(8.323- 0521) at 6Kfa X0.6525 hy15144+ 452512566-67 -151.434) repired for PoMk Work dent F001110- :9.994 K hyhgt wp 161.49 KJ /K bailer Sopiishhyaas43-161-43 dS(3.983 KJ Kg Heat Reyected SA : h-hy 1727.330-1S1494 1575.A KK Condenier Thermat etticienctn) 0.3154-385