1 8 1 295 t cons 1 s cen54261ch07qxd 111803 957

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Unformatted text preview: nstant specific heats for air: T2 T1 FIGURE 7–39 The use of υr data for calculating the final temperature during an isentropic process (Example 7–10). s const. υ1 υ2 T, K t. = υ2 co Isentropic compression AIR P1 = 95 kPa T1 = 295 K V1 =8 V2 k1 ns 2 FIGURE 7–38 Schematic and T-s diagram for Example 7–10. 1 8 υ1 = 295 t. cons 1 s cen54261_ch07.qxd 11/18/03 9:57 AM Page 303 303 CHAPTER 7 The specific heat ratio k also varies with temperature, and we need to use the value of k corresponding to the average temperature. However, the final temperature is not given, and so we cannot determine the average temperature in advance. For such cases, calculations can be started with a k value at the initial or the anticipated average temperature. This value could be refined later, if necessary, and the calculations can be repeated. We know that the temperature of the air will rise considerably during this adiabatic compression process, so we guess that the average temperature will be about 450 K. The k value at this anticipated average temperature is determined from Table A–2b to...
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This document was uploaded on 11/28/2012.

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