Concept explainers
a)
The final equilibrium temperature.
a)
Answer to Problem 97P
The final equilibrium temperature is
Explanation of Solution
Write the expression for the energy balance equation for closed system.
Here, energy transfer into the control volume is
Write the expression to calculate the mass of the air.
Here, mass of the air is
Conclusion:
Substitute 0 for
Here, mass of the air is
From the Table A-2, “Ideal-gas specific heats of various common gases”, obtain the properties for air.
From the Table A-3, “Properties of common liquids, solids, and foods”, the specific heat of water
Substitute
Substitute
Thus, the final equilibrium temperature is
b)
The amount of heat transfer to the air.
b)
Answer to Problem 97P
The amount of heat transfer to the air is
Explanation of Solution
Write the expression to calculate the heat transfer
Conclusion:
Substitute
Thus, the amount of heat transfer to the air is
c)
The entropy generation.
c)
Answer to Problem 97P
The entropy generation is
Explanation of Solution
Write the expression for the entropy balance equation of the system.
Here, rate of net entropy in is
Write the expression to calculate the final pressure
Here, final temparature is
Conclusion:
Substitute
Substitute 0 for
Substitute
Thus, the entropy generation is
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Chapter 7 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
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