Concept explainers
The final pressure of the two rigid tanks.
The amount of heat transfer to the two rigid tanks.
Answer to Problem 138RP
The final pressure of the two rigid tanks is
The amount of heat transfer to the two rigid tanks is
Explanation of Solution
Write the expression for the energy balance equation.
Here, the total energy entering the system is
Simplify Equation (I) and write energy balance two rigid tanks.
Here, the work to be done into the system is
Take the two rigid tanks as the system.
Substitute
Here, the total mass of the two rigid tank is
Determine the initial specific volume of the tank A.
Here, the specific volume of the saturated liquid phase is
Determine the initial internal energy of the tank A.
Here, the specific internal energy of the saturated liquid phase is
Determine the total mass of the two rigid tanks.
Determine the final specific volume of the two rigid tanks.
Here, the total volume of the two tanks is
Determine the final dryness fraction of the two rigid tanks.
Here, the specific volume change upon vaporization is
Determine the final internal energy of the tanks.
Conclusion:
For Tank A:
From the Table A-5, “Saturated water-Pressure”, obtain the value of the specific volume of liquid, the specific volume of vapour, the specific internal energy of liquid, and the specific internal energy change upon vaporization at 400 kPa of pressure and 0.80 of dryness fraction of water in tank A as:
Substitute
Substitute
For tank B:
The unit conversion of pressure from kPa to MPa.
From the Table A-5, “Superheated water-Pressure”, obtain the value of the initial specific volume of liquid and the initial specific internal energy of liquid at 0.2 MPa of pressure and
Substitute
Substitute
From the Table A-4, “Saturated water-Temperature”, obtain the value of the specific volume of liquid, the specific volume of vapour, the specific internal energy of liquid, the specific internal energy change upon vaporization, and the final pressure of the saturated mixture of liquid-vapour at
Thus, the final pressure of the two rigid tanks is
Substitute
Substitute
Substitute
Thus, the amount of heat transfer to the two rigid tanks is
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