p read p 2p r2 p1 r1 read pr1 figure 737 the

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: P1 T1 P2 T2 Pr1 T1 Pr2 s const. υr2 υr1 T . . . T2 T1 T2/Pr2 T1/Pr1 The quantity T/Pr is a function of temperature only and is defined as relative specific volume υr. Thus, υ2 υ1 Process: isentropic Given: P1, T1, and P2 Find: T2 (7–50) . . . . . . Pr . . . P read P = 2P . r2 P1 r1 . . read Pr1 . . . FIGURE 7–37 The use of Pr data for calculating the final temperature during an isentropic process. cen54261_ch07.qxd 11/18/03 9:57 AM Page 302 302 FUNDAMENTALS OF THERMAL-FLUID SCIENCES Equations 7–49 and 7–50 are strictly valid for isentropic processes of ideal gases only. They account for the variation of specific heats with temperature and therefore give more accurate results than Eqs. 7–42 through 7–47. The values of Pr and υr are listed for air in Table A–21. EXAMPLE 7–10 Isentropic Compression of Air in a Car Engine Air is compressed in a car engine from 22°C and 95 kPa in a reversible and adiabatic manner. If the compression ratio V1/V2 of this piston-cylinder...
View Full Document

Ask a homework question - tutors are online