Concept explainers
(a)
The final temperature in the cylinder at equilibrium condition.
(a)
Answer to Problem 107RP
The final temperature in the cylinder at equilibrium condition is
Explanation of Solution
Write the ideal gas equation to calculate the mass of the gas
Here, initial pressure of the gas is
Write the energy balance equation for the entire system considering it as a stationary closed system.
Here, net energy input to the system is
Conclusion:
Refer the Table A-1E of “Molar mass, gas constant, and critical-point properties”, obtain the gas constants of Nitrogen and Helium as
Refer the Table A-2E of “Ideal-gas specific heats of various common gases”, obtain the specific heats of Nitrogen, copper, and Helium as
Substitute
Substitute
Calculate the temperature of piston as the average temperature of nitrogen and helium
Substitute
Thus, the final temperature in the cylinder at equilibrium condition is
Final temperature at equilibrium condition is same even if the piston is restricted from moving.
(b)
The amount of wasted work potential for the process.
The amount of wasted work potential for the process when piston is restricted from moving.
(b)
Answer to Problem 107RP
The amount of wasted work potential for the process is
The amount of wasted work potential for the process when piston is restricted from moving is
Explanation of Solution
Write the expression to calculate the total number of moles in the cylinder
Write the expression to calculate the pressure from ideal gas expression.
Here, universal gas constant is
Write the entropy generation
Here, entropy input to the system is
Write the expression to calculate the exergy destroyed
Here, the surrounding’s temperature is
Write the formula to calculate the entropy generation when the piston is restricted to move.
Conclusion:
Refer the Table A-1E of “Molar mass, gas constant, and critical-point properties”, obtain the molar masses of Nitrogen and Helium as
Substitute
Substitute
Substitute
Substitute
Thus, the amount of wasted work potential for the process is
Substitute
Substitute
Thus, the amount of wasted work potential for the process when piston is restricted from moving is
Want to see more full solutions like this?
Chapter 8 Solutions
THERMODYNAMICS
- Refrigerant-134a enters an adiabatic compressor as saturated vapor at 100 kPa at a rate of 0.7 m3 /min and exits at 1-MPa pressure. If the isentropic efficiency of the compressor is 87 percent, determine the temperature of the refrigerant at the exit of the compressor.arrow_forwardA 0.05-m3 rigid tank initially contains refrigerant134a at 0.8 MPa and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a at 1.2 MPa and 40°C. Now the valve is opened, and the refrigerant is allowed to enter the tank. The valve is closed when it is observed that the tank contains saturated liquid at 1.2 MPa. Determine the mass of the refrigerant that has entered the tankarrow_forwardDetermine the final temperature when air is expanded isentropically from 1000 kPa and 477°C to 100 kPa in a piston–cylinder devicearrow_forward
- Refrigerant-134a at 700 kPa, 70°C, and 8 kg/min is cooled by water in a condenser until it exists as a saturated liquid at the same pressure. The cooling water enters the condenser at 300 kPa and 15°C and leaves at 25°C at the same pressure. Determine the mass flow rate of the cooling water required to cool the refrigerant.arrow_forwardNitrogen gas is compressed from 80 kPa and 27°C to 480 kPa by a 10-kW compressor. Determine the mass flow rate of nitrogen through the compressor, assuming the compression process to be isothermal.arrow_forwardSteam at 100 psia and 650F is expanded adiabatically in a closed system to 10 psia. Determine the work produced, in Btu/lbm, and the final temperature of steam for an isentropic expansion efficiency of 80 percent.arrow_forward
- In large compressors, the gas is often cooled while being compressed to reduce the power consumed by the compressor. Explain how cooling the gas during a compression process reduces the power consumption.arrow_forwardA steam turbine operates with 5 kg / s of steam from 4 MPa and 500 degrees Celsius to 50 kPa. If the humidity at the outlet of the turbine is 5%. Determine isentropic efficiency of the turbine.arrow_forwardIn a power plant, water vapor with a flow rate of 35 kg / s enters the adiabatic turbine at a pressure of 10 MPa and a temperature of 500° C, and comes out at a pressure of 150 kPa and 92% dryness at a speed of 200 m / s. The velocity at the turbine inlet is negligibly small compared to the outlet. The water coming out of the turbine is cooled in the condenser by cooling water whose inlet temperature is 20° C. At the condenser outlet, the cooling water temperature rises to 40 ° C, the steam pressure is 100 kPa, the temperature is 60 ° C. Coolant can be regarded as compressed liquid.a) Power generated in the turbineb)Heat transferred to the cooling water in the condenserc)Calculate the cooling water flowarrow_forward
- In a gas turbine plant, air enters the compressor at ambient conditions of 100 kPa and 25°C with a low velocity and exits at 1 MPa and 382°C with a velocity of 80 m/s. The compressor is cooled at a rate of 1500 kJ/min, and the power input to the compressor is 230 kW. (i) Identify the enthalpy of air (units: kJ/kg) at the compressor inlet, (ii) Identify the enthalpy of air (units: kJ/kg) at the compressor exit, and (iii) Determine the mass flow rate of air (units: kg/s) through the compressor.arrow_forwardA 5-ft3 rigid tank initially contains refrigerant-134a at 60 psia and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a at 140 psia and 80F. The valve is now opened, allowing the refrigerant to enter the tank, and is closed when it is observed that the tank contains only saturated liquid at 100 psia. Determine (a) the mass of the refrigerant that entered the tank, (b) the amount of heat transfer with the surroundings at 708F, and (c) the entropy generated during this process.arrow_forwardTen cu ft of air at 30 psia and 400°F is cooled to 140°F at constant volume. What is the change in entropy ? Group of answer choices -0. 0581 Btu/oR +0. 20 Btu/oR 0 +0. 581 Btu/oRarrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY