The thermal efficiency of the cycle.
Answer to Problem 68P
The thermal efficiency of the cycle is
Explanation of Solution
Refer to Table A-1E, Obtain the molar masses of
Refer to Table A-2Ea, obtain the constant-pressure specific heats of the gases at room temperature.
Write the mass of
Here, the mole number of
Write the mass of
Here, the mole number of
Write the mass of
Here, the mole number of
Write the mass of
Here, the mole number of
Write the equation to calculate the total mass of the mixture.
Calculate the mass fraction of
Calculate the mass fraction of
Calculate the mass fraction of
Calculate the mass fraction of
Calculate the molar mass of the gas mixture.
Write the equation to calculate the constant-pressure specific heat of the mixture.
Here, mass fraction of
Calculate the gas constant of the mixture.
Here, the universal gas constant is
Calculate the constant volume specific heat.
Calculate the specific heat ratio.
Refer to Table A-2Ea, obtain the air properties at room temperature.
Calculate the constant pressure and constant velocity specific heat on an average.
Calculate the average specific heat ratio.
Calculate the final temperature during the compression process.
Here, the compression ratio is r.
Express the heat addition process.
Here, specific heat at constant volume on an average is
Write the equation to calculate the temperature during the expansion process.
Express the heat rejection process.
Calculate the thermal efficiency of the cycle.
Conclusion:
Consider 100 lbmol of this mixture.
Substitute 25 lbmol for
Substitute 224 lbm for
Substitute 224 lbm for
Substitute 3188 lbm for
Substitute 0.07026 for
Substitute
Substitute
Substitute
Substitute
Substitute 1.328 for k and 1.4 for
Substitute 1.4 for
Substitute
Substitute 1.328 for
Substitute
Substitute
Thus, the thermal efficiency of the cycle is
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Chapter 13 Solutions
Thermodynamics: An Engineering Approach ( 9th International Edition ) ISBN:9781260092684
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