743 into eq 742 and simplifying p2 p1 s const 1 2 k

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Unformatted text preview: entropic relation is obtained in a similar manner from Eq. 7–34 with the following result: T2 T1 s const. P2 P1 (k 1)/k (ideal gas) (7–43) The third isentropic relation is obtained by substituting Eq. 7–43 into Eq. 7–42 and simplifying: P2 P1 s const. υ1 υ2 k (ideal gas) (7–44) Equations 7–42 through 7–44 can also be expressed in a compact form as Tυ k 1 TP(1 k)/k Pυ k (( T2 T1 s = const. = (k –1)/k (( P2 P1 = υ1 υ2 k –1 (( *ideal gas VALID FOR *isentropic process *constant specific heats constant constant constant (7–45) (ideal gas) (7–46) (7–47) The specific heat ratio k, in general, varies with temperature, and thus an average k value for the given temperature range should be used. Note that the ideal-gas isentropic relations above, as the name implies, are strictly valid for isentropic processes only when the constant-specific-heat assumption is appropriate (Fig. 7–36). Variable Specific Heats (Exact Analysis) FIGURE 7–36 The isentropic relations of ideal gases are valid for the isentropic processes of ideal gases...
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This document was uploaded on 11/28/2012.

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