(a)
The power output of the turbine.
(a)
Answer to Problem 95RP
The power output of the turbine is
Explanation of Solution
Write the energy rate balance equation for one inlet and one outlet system.
Here, the rate of heat transfer is
The argon flows at steady state through the turbine. Hence, the rate of change in net energy of the system becomes zero.
Heat loss occurs to the surrounding at the exit. Neglect the potential energy changes. The work done is by the system (turbine) and the work done on the system is zero i.e.
The Equations (II) reduced as follows to obtain the work input.
Here, the
Write formula for enthalpy departure factor
Here, the enthalpy at ideal gas state is
Rearrange the Equation (III) to obtain
Refer Equation (IV) express as two states of enthalpy difference (initial and final).
The change in enthalpy at ideal state is expressed as follow.
Here, the specific heat is
Substitute
Refer Table A-1E, “Molar mass, gas constant, and critical-point properties”.
The critical temperature and pressure of argon gas is as follows.
The reduced pressure
The reduced pressure
At initial:
Refer Figure A-29, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Refer Figure A-30, “Generalized entropy departure chart”.
The entropy departure factor
At final:
Refer Figure A-29E, “Generalized enthalpy departure chart”.
The enthalpy departure factor
Refer Figure A-30, “Generalized entropy departure chart”.
The entropy departure factor
Refer Table A-2E, “Ideal-gas specific heats of various common gases”.
The specific heat at constant pressure of argon is
The gas constant of argon is
Conclusion:
Substitute 0.04 for
Substitute
Thus, the power output of the turbine is
(b)
The exergy destruction associated with the process.
(b)
Answer to Problem 95RP
The exergy destruction associate with process is
Explanation of Solution
Write the entropy balance equation for closed system.
Here, the entropy input is
Rewrite the Equation (VII) as follows by substituting 0 for
Here, mass flow rate is
Write the formula for change in entropy
Here, the gas constant is R, the specific heat at constant pressure is
Write the formula for change in entropy
Here, the entropy departure factor is
Write the formula for exergy destruction associate with process.
Substitute
Conclusion:
Substitute
Substitute
Substitute
Thus, the exergy destruction associate with process is
Want to see more full solutions like this?
Chapter 12 Solutions
THERMODYNAMICS: AN ENGINEERING APPROACH
- Argon gas enters an adiabatic compressor at 120 kPa and 30°C with a velocity of 20 m/s and exits at 1.2 MPa, 530°C, and 80 m/s. The inlet area of the compressor is 130 cm2 . Assuming the surroundings to be at 25°C, determine the reversible power input and exergy destroyed.arrow_forwardSteam at 6 MPa and 500°C enters a two-stage adiabatic turbine at a rate of 15 kg/s. Ten percent of the steam is extracted at the end of the first stage at a pressure of 1.2 MPa for other use. The remainder of the steam is further expanded in the second stage and leaves the turbine at 20 kPa. Determine the power output of the turbine, assuming the turbine has an isentropic efficiency of 88 percent.arrow_forwardDuring a steady flow process, the pressure of the working substance drops from 200 to 20 psia. The speed increases from 200 to 1000 ft/s. The internal energy decreases by 25 BTU/lb and the specific volume increases from 2 to 10 ft3/lb. Determine the work done per pound of substance (BTU/lb)arrow_forward
- Steam enters an adiabatic turbine steadily at 7 MPa, 500°C, and 45 m/s and leaves at 100 kPa and 75 m/s. If the power output of the turbine is 5 MW and the isentropic efficiency is 77 percent, determine the mass flow rate of steam through the turbine.arrow_forwardWhat is entropy and its application?arrow_forwardAir in a large building is kept warm by heating it with steam in a heat exchanger. Saturated water vapor enters this unit at 35°C at a rate of 10,000 kg/h and leaves as saturated liquid at 32°C. Air at 1-atm pressure enters the unit at 20°C and leaves at 30°C at about the same pressure. Determine the rate of entropy generation associated with this process.arrow_forward
- 5kg of steam is generated at a pressure of 10 bar from feed water at a temperature of 25°C. Calculate, with the help of steam tables, the enthalpy and entropy of steam, when (a) the steam is dry and saturated; and (b) the steam is superheated up to a temperature of 300°C. Take specific heat for superheated steam as 2.1 kJ/kg K and specific heat for water as 4.187 kJ/ kg K.arrow_forwardAn adiabatic diffuser at the inlet of a jet engine increases the pressure of the air that enters the diffuser at 11 psia and 30°F to 20 psia. What will the air velocity at the diffuser exit be if the diffuser isentropic efficiency, defined as the ratio of the actual kinetic energy change to the isentropic kinetic energy change, is 82 percent and the diffuser inlet velocity is 1200 ft/s?arrow_forward8-90 Steam enters a turbine at 9 MPa, 600 degrees C, and 60 m/s and leaves at 20 kPa and 90 m/s with a moisture content of 5 percent. The turbine is not adequately insulated and it estimated that heat is lost from the turbine at a rate of 220 kW. The power output of the turbine is 4.5 MW. Assuming the surroundings to be at 25 degrees C, determine (a) the reversible power output of the turbine, (b) the exergy destroyed within the turbine, and (c) the second-law efficiency of the turbine. (d) Also, estimate the possible increase in the power output of the turbine if the turbine were perfectly insulated. (Please type answer no write by hend)arrow_forward
- Steam at 3 Mpa and 450 oC is expanded to 40 kPa in an adiabatic turbine with an isentropic efficiency of 89 percent. Determine the power produced by this turbine, in kW, when the mass flow rate is 2.6 kg/s. h1 (kJ/kg) Format : 6647.4 s1 (kJ/kgK) Format : 9.0424 x2s Format : 0.7878 h2s (kJ/kg) Format : 2778.7 Wa_out (kW) Format : 9372.2arrow_forwardIn a food processing industry, steam and water are mixed to produce a continuous supply of hot water. 13 kg/sec of water with a specific enthalpy of 50 kJ/kg and 2 kg/sec of steam with a specific enthalpy of 2670 kJ/kg flow into a mixing chamber. If the heat loss from the chamber is 780 watts, determine the specific enthalpy of the hot water produced.arrow_forwardRefrigerant-134a at 140 kPa and 210C is compressed by an adiabatic 1.3-kW compressor to an exit state of 700 kPa and 60C. Neglecting the changes in kinetic and potential energies, determine (a) the isentropic efficiency of the compressor, (b) the volume flow rate of the refrigerant at the compressor inlet, in L/min, and (c) the maximum volume flow rate at the inlet conditions that this adiabatic 1.3-kW compressor can handle without violating the second law.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