Concept explainers
(a)
The final pressure in the tank.
(a)
Answer to Problem 118P
The final pressure in the tank is
Explanation of Solution
At the final observation, the valve is closed and the tank composed with one-half water and vapor at the temperature of
Hence, the pressure
Refer Table A-4E, “Saturated water-Temperature table”.
The saturation pressure corresponding to the temperature of
Conclusion:
Hence, the pressure of the mixture in the tank at the final state is
(b)
The amount of steam entered in the tank.
(b)
Answer to Problem 118P
The amount of steam entered in the tank is
Explanation of Solution
Write the equation of mass balance.
Here, the inlet mass is
The change in mass of the system for the control volume is expressed as,
Here, the suffixes 1 and 2 indicates the initial and final states of the system.
Consider the given rigid tank as the control volume.
At final state, the valve is close and the steam is not allowed to exit, i.e.
Rewrite the Equation (I) as follows.
At initial state, the tank consist of saturated water vapor
Write the formula for mass of steam
Here, the volume is
At final state, the tank consist of mixture of vapor
Write the formula for mass of steam
Here, the suffixes
It is given that the tank consist of one-half of the volume of the tank is occupied by liquid water.
At the initial state (1):
The tank consist of saturated water vapor
Refer Table A-4E, “Saturated water-Temperature table”.
Obtain the initial specific volume
At the final state (2):
The tank consist of mixture of vapor
Refer Table A-4E, “Saturated water-Temperature table”.
Obtain the final fluid and gaseous specific volume corresponding to the temperature of
Conclusion:
Substitute
Substitute
Substitute
Thus, the amount of steam entered in the tank is
(c)
The amount of the heat transfer.
(c)
Answer to Problem 118P
The amount of the heat transfer is
Explanation of Solution
Write the energy balance equation.
Here, the heat transfer is
Since the tank is not insulated, the heat transfer occurs through the tank wall. In control volume, there is no work transfer, i.e.
The Equation (V) reduced as follows.
At the final state, the tank is composed of vapor and liquid. Hence, the final state energy is expressed as follows.
At the line (while entering the tank):
The supply line consist of superheated water vapor.
Refer Table A-6E, “Superheated water”.
Obtain the line enthalpy
At the initial state (1):
The tank consist of saturated water vapor
Refer Table A-4E, “Saturated water-Temperature table”.
Obtain the initial internal energy
At the final state (2):
The tank consist of mixture of vapor
Refer Table A-4E, “Saturated water-Temperature table”.
Obtain the final fluid and gaseous internal energies corresponding to the temperature of
Conclusion:
Substitute
Substitute
Here, the negative sign indicates that the heat transfer occurs from the tank to the surrounding.
Thus, the amount of the heat transfer is
Want to see more full solutions like this?
Chapter 5 Solutions
Thermodynamics: An Engineering Approach
- A 0.06-m3 rigid tank initially contains refrigerant- 134a 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 36°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 (a) the mass of the refrigerant that has entered the tank and (b) the amount of heat transfer.arrow_forwardSteam enters a turbine steadily at a flow rate of 1 kg/s at 7 MPa and 500 degrees and exits as saturated steam at 40 kPa. If there is a heat loss of 10 kW from the turbine, what will be the power produced by the turbine?arrow_forwardRefrigerant-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_forward
- Steam flows steadily through a turbine at a rate of 45,000 lbm/h, entering at 1000 psia and 900°F and leaving at 5 psia as saturated vapor. If the power generated by the turbine is 4 MW, determine the rate of heat loss from the steam.arrow_forwardA 0.25 m^3 rigid tank contains refrigerant-134a at 0.8 MPa and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a at 1.25 MPa and 30 ∘C. 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 1.25 MPa. Determine the heat transfer and the mass of the refrigerant that has entered the tank.arrow_forwardA 0.8-m3 rigid tank contains carbon dioxide (CO2) gas at 250 K and 100 kPa. A 500-W electric resistance heater placed in the tank is now turned on and kept on for 40 min, after which the pressure of CO2 is measured to be 175 kPa. Assuming the surroundings to be at 300 K and using constant specific heats, determine the net amount of heat transfer from the tank.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_forwardA 200-m3 rigid tank contains compressed air at 1 MPa and 300 K. Determine how much work can be obtained from this air if the environment conditions are 100 kPa and 300 K.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
- A student living in a 4 - m 5 - m 3 - m dormitory room turns on her 100 - W fan before she leaves the room on a summer day, hoping that the room will be cooler when she comes back in the evening. Assuming all the windows are tightly closed and disregarding any heat transfer through the walls and the windows, determine the temperature in the room when she comes back 8 h later. Use specific heat values at room temperature, and assume the room to be at 100 kPa and 20 ° C in the morning when she leaves.arrow_forwardA hair dryer is basically a duct in which a few layers of electric resistors are placed. A small fan pulls the air in and forces it through the resistors where it is heated. Air enters a 1200-W hair dryer at 100 kPa and 22°C and leaves at 47°C. The cross-sectional area of the hair dryer at the exit is 60 cm2 . Neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine the volume flow rate of air at the inlet.arrow_forwardA hair dryer is basically a duct in which a few layers of electric resistors are placed. A small fan pulls the air in and forces it through the resistors where it is heated. Air enters a 1200-W hair dryer at 100 kPa and 22°C and leaves at 47°C. The cross-sectional area of the hair dryer at the exit is 60 cm2 . Neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine the velocity of the air at the exit.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