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
Want to see more full solutions like this?
Chapter 13 Solutions
Thermodynamics: An Engineering Approach
- QUESTION : Which of the two gases—helium or—nitrogenhas the higher final temperature as it is compressed isentropically from 160 kPa and 25°C to 1 MPa in a closed system? Use the table containing the ideal gas specific heats of various common gases Which will have the higher final temperature? Helium or nitrogen?? Hint : It is compressed isentropically from 160 KPA * arrow_forwardSelect the correct expressions of the entropy change for the ideal gases with constant specific heats for arbitrary processes ___________ A. B. C. D.arrow_forwardThe isentropic relations of ideal gases are valid for the isentropic processes of ideal gases onlyarrow_forward
- A stream of outdoor air is mixed with a stream of return air in an air-conditioning system that is operated at 101.325 kPa barometric pressure. The flow rate of outdoor air is 2.0 kg/s and its condition is 35°C DBT and 25°C WBT temperatures. The flow rate of return air is 3.0 kg/s and its condition is 24°C DBT and 50% RH. If the ambient pressure is 98 kPaa, determine the following: 1. Enthalpy of the mixture in kJ/kg 2. Humidity ratio 3. Dry bulb temperature of the mixture in °Carrow_forwardSteam of 1.4MN/m2 and of dryness fraction 0.7 is throttled to 0.11MN/m2 determine the dryness fraction of the steam after throttling?arrow_forwardThe volumetric analysis of a mixture of gases is 35 percent ethylene and 65 percent ethane.This mixture is heated from 175◦C to 335◦C while flowing at a rate of 0.28 kg/s through a heat exchanger in which pressure is maintained at 270 kPa. Determine the rate of heat transfer to the mixture.arrow_forward
- Steam (H2O) enters a turbine at 35 m/s and specific enthalpy of 3500 kJ/kg. Thesteam leaves the turbine as a mixture of vapor and liquid having a velocity of 60m/s and a specific enthalpy of 2400 kJ/kg. If the flow through the turbine is steady,adiabatic, and changes in elevation are negligible, calculate the work output per unitmass (kJ/kg) for the turbine.arrow_forwardWhat is the enthalpy of the air-vapor mixture at 70% RH and 33°C when the barometricpressure is 101 kPa? At 33°C: Psat = 5.628, hg = 2565.3 kJ/kgarrow_forwardThe mass flow rate of gas entering nozzle is 25 /m3 . The inlet total pressure= 200kPa and inlet total temperature = 900 K. The exit pressure = 80 kPa ,and isentropic efficiency =92%.Determine the density of gases at the exit and the exit area . (Specific heat is 1100 J/kg.K and gas constant 287 J/kg.K ).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