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Schematic and Ts diagram
for Example 7–5. cen54261_ch07.qxd 11/18/03 9:57 AM Page 286 286
FUNDAMENTALS OF THERMALFLUID SCIENCES The inlet state is completely specified since two properties are given. But only
one property (pressure) is given at the final state, and we need one more property to fix it. The second property comes from the observation that the process
is reversible and adiabatic, and thus isentropic. Therefore, s2 s1, and h1
s1 State 1: P1
T1 5 MPa
450°C State 2: P2
s2 1.4 MPa
s1 3316.2 kJ/kg
6.8186 kJ/kg · K h2 2966.6 kJ/kg Then the work output of the turbine per unit mass of the steam becomes wout 7–5 I h1 h2 3316.2 2966.6 349.6 kJ/kg PROPERTY DIAGRAMS INVOLVING ENTROPY Property diagrams serve as great visual aids in the thermodynamic analysis of
processes. We have used Pυ and Tυ diagrams extensively in previous chapters in conjunction with the first law of thermodynamics. In the secondlaw
analysis, it is very helpful to plot the processes on diagrams for which one of
the coordinates is entropy. The two diagrams commonly u...
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 Spring '09

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