Explanation Show the T − s diagram of the process. Write the formula to calculate stream exergy at the turbine inlet when the valve is partially closed ( ψ 1 ) . ψ 1 = h 1 − h 0 − T 0 ( s 1 − s 0 ) (I) Here, enthalpy of steam at state 1 is h 1 , enthalpy of steam at the surrounding is h 0 , entropy of steam at state 1 is s 1 , entropy of steam at the surrounding is s 0 and surrounding temperature is T 0 . Write the formula to calculate second-law efficiency of the system ( η II ) . η II = w out w rev (II) Here, work output of the system is w out and reversible work done on the system is w rev . Write the formula to calculate work output of the system ( w out ) . w out = h 1 − h 3 Here, enthalpy of steam at state 3is h 3 . Write the formula to calculate reversible work done on the system ( w rev ) . w rev = h 1 − h 3 − T 0 ( s 1 − s 3 ) Here, entropy of steam at state 3 is s 3 . Conclusion: Refer Table A-4, "Saturated water-Temperature table", obtain the following properties of steam at the temperature of 25 ° C and pressure of 100 kPa . h 0 = h f = 104.83 kJ / kg s 0 = s f = 0.3672 kJ / kg ⋅ K Refer Table A-6, "Superheated water", obtain the following properties of steam at the temperature of 600 ° C and pressure of 6 MPa . h 1 = h 2 = 3658.8 kJ / kg s 1 = s 2 = 7.1693 kJ / kg ⋅ K Substitute 3658.8 kJ / kg for h 1 , 104.83 kJ / kg for h 0 , 25 ° C for T 0 , 7.1693 kJ / kg ⋅ K for s 1 and 0

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Chapter 8.8, Problem 100RP

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The stream exergy at the turbine inlet when the valve is partially closed.

The second law of efficiency of the systemwhen the valve is partially closed.

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Chapter 8.8, Problem 99RP

Chapter 8.8, Problem 101RP

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The stream exergy at the turbine inlet when the valve is partially closed. The second law of efficiency of the systemwhen the valve is partially closed.

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The stream exergy at the turbine inlet when the valve is partially closed.

The second law of efficiency of the systemwhen the valve is partially closed.