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Unformatted text preview: et, out QH QL 2 Wnet SOLUTION Recall that the Carnot cycle is made up of two reversible isothermal (T
constant) processes and two isentropic (s
constant) processes.
These four processes form a rectangle on a TS diagram, as shown in Fig. 7–19.
On a TS diagram, the area under the process curve represents the heat transfer for that process. Thus the area A12B represents QH, the area A43B represents QL, and the difference between these two (the area in color) represents
the net work since s FIGURE 7–17
The isentropic process appears as a
vertical line segment on a Ts diagram. TL 4 A
S1 = S4 3 B
S 2 = S3 S FIGURE 7–19
The TS diagram of a Carnot cycle
(Example 7–6). cen54261_ch07.qxd 11/18/03 9:57 AM Page 288 288
FUNDAMENTALS OF THERMALFLUID SCIENCES Therefore, the area enclosed by the path of a cycle (area 1234) on a TS diagram represents the net work. Recall that the area enclosed by the path of a cycle also represents the net work on a PV diagram. 7–6 Entropy,
kJ/kg K GAS LIQUID
SOLID FIGURE 7–20
The level of molecular disorder
(entropy) of a substance increases as it
melts or evaporates. I WHAT IS ENTROPY?...
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 Spring '09

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