Concept explainers
a)
The final temperature in each tank A and tank B.
a)
Answer to Problem 201RP
The final temperature in tank A is
The final temperature in tank B is
Explanation of Solution
Write the formula to calculate the specific volume of steam from tables
Here, specific volume of saturated liquid is
Write the formula to calculate the specific internal energy of steam from tables
Here, specific internal energy of saturated liquid is
Write the formula to calculate the specific entropy of steam from tables
Here, specific entropy of saturated liquid is
Write the formula to calculate the mass of the steam
Here, volume of the steam is
Write the expression for the mass balance.
Here, mass of the water entering into the system is
Write the expression for the energy balance Equation for a closed system.
Here, net energy transfer into the control volume is
Conclusion:
From Table A-5, “Saturated water-Pressure table”, obtain the following properties of water at initial pressure
Substitute
Substitute
Substitute
From Table A-5, “Saturated water-Pressure table”, obtain the following properties of water at final pressure
Here, final temperature of steam in tank A is
The steam in tank A undergoes isentropic process, Thus final specific entropy of steam in tank A
Substitute
Substitute
Substitute
From Table A-6, “Superheated water”, note the properties for steam in tank B initially at the pressure of
Substitute
Substitute
Substitute
Rewrite the Equation (V) to calculate the final total mass of steam in tank B
Here, initial mass of steam in tank B is
Substitute
Substitute
Substitute
From first law of thermodynamics, Re-write the Equation (VI) for heat transfer
Here, work done is
Substitute
From Table A-5, “Saturated water-Temperature table”, obtain the following properties of water at
Here, the temperature of the steam in tank at final state is
Thus, the final temperature of steam in tank A is
b)
The entropy generated during the process.
b)
Answer to Problem 201RP
The entropy generated during the process is
Explanation of Solution
Write the expression for the entropy balance Equation of the system.
Here, rate of net entropy in is
Conclusion:
Re-write the Equation (IX) for the entropy generated
Here, temperature of the surroundings is
Substitute
Thus, the entropy generated during this process is
Want to see more full solutions like this?
Chapter 7 Solutions
Thermodynamics: An Engineering Approach
- Steam enters an adiabatic turbine at 8 MPa and 500°C at a rate of 2.7 kg/s and leaves at 20 kPa. If the power output of the turbine is 2.5 MW, determine the temperature of the steam at the turbine exit. Neglect kinetic energy changesarrow_forwardWhat is the minimum internal energy that steam can achieve as it is expanded adiabatically in a closed system from 1500 kPa and 320°C to 100 kPa?arrow_forwardAir enters a compressor at ambient conditions of 100 kPa and 20°C at a rate of 6.2 m3 /s with a low velocity and exits at 900 kPa, 60°C, and 80 m/s. The compressor is cooled by cooling water that experiences a temperature rise of 10°C. The isothermal efficiency of the compressor is 70 percent. Determine the second-law efficiency.arrow_forward
- Refrigerant-134a enters an adiabatic compressor as saturated vapor at 30 psia at a rate of 20 ft3 /min and exits at 70 psia pressure. If the isentropic efficiency of the compressor is 80 percent, determine the second-law efficiency of the compressor. Assume the surroundings to be at 75°F.arrow_forwardRefrigerant-134a at 140 kPa and –10°C is compressed by an adiabatic 0.5-kW compressor to an exit state of 700 kPa and 60°C. Neglecting the changes in kinetic and potential energies and assuming the surroundings to be at 27°C, determine the second-law efficiency of the compressor.arrow_forwardAn adiabatic diffuser at the inlet of a jet engine increases the pressure of the air that enters the diffuser at 11 psia and 30°F to 20 psia. What will the air velocity at the diffuser exit be if the diffuser isentropic efficiency, defined as the ratio of the actual kinetic energy change to the isentropic kinetic energy change, is 82 percent and the diffuser inlet velocity is 1200 ft/s?arrow_forward
- Steam enters an adiabatic turbine at 800 psia and 900F and leaves at a pressure of 40 psia. Determine the maximum amount of work that can be delivered by this turbine.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_forwardSteam enters an adiabatic turbine at 5 MPa and 450°C and leaves at a pressure of 1.4 MPa. Determine the work output of the turbine per unit mass of steam if the process is reversiblearrow_forward
- Air enters the compressor of a gas-turbine plant at ambient conditions of 100 kPa and 25 °C with a low velocity and exits at 1 MPa and 347 °C with a velocity of 90 m/s. The compressor is cooled at a rate of 1500 kJ/min, and the power input to the compressor is 250 kW. Determine the mass flow rate of air through the compressor. (Hint: Use Table A-17 of the Booklet for the properties of air.)arrow_forwardRefrigerant-134a at 140 kPa and 210C is compressed by an adiabatic 1.3-kW compressor to an exit state of 700 kPa and 60C. Neglecting the changes in kinetic and potential energies, determine (a) the isentropic efficiency of the compressor, (b) the volume flow rate of the refrigerant at the compressor inlet, in L/min, and (c) the maximum volume flow rate at the inlet conditions that this adiabatic 1.3-kW compressor can handle without violating the second law.arrow_forwardRefrigerant-134a at 140 kPa and –10°C is compressed by an adiabatic 0.5-kW compressor to an exit state of 700 kPa and 60°C. Neglecting the changes in kinetic and potential energies and assuming the surroundings to be at 27°C, determine the isentropic efficiency.arrow_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