Unformatted text preview: a are the required work inputs to the compressor for the
reversible isothermal and actual cases, respectively. COMPRESSOR Air Cooling
water FIGURE 7–52
sometimes intentionally cooled to
minimize the work input. cen54261_ch07.qxd 11/18/03 9:57 AM Page 316 316
FUNDAMENTALS OF THERMAL-FLUID SCIENCES EXAMPLE 7–15 Effect of Efficiency on Compressor Power Input Air is compressed by an adiabatic compressor from 100 kPa and 12°C to a
pressure of 800 kPa at a steady rate of 0.2 kg/s. If the isentropic efficiency of
the compressor is 80 percent, determine (a) the exit temperature of air and (b)
the required power input to the compressor. SOLUTION A sketch of the system and the T-s diagram of the process are given
in Fig. 7–53.
Assumptions 1 Steady operating conditions exist. 2 Air is an ideal gas. 3 The
changes in kinetic and potential energies are negligible. 4 The compressor is
Analysis (a) We know only one property (pressure) at the exit state, and we
need to know one more to fix the state...
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This document was uploaded on 11/28/2012.
- Spring '09