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Unformatted text preview: (or other) software, determine the
work input to a multistage compressor for a
given set of inlet and exit pressures for any number of stages.
Assume that the pressure ratio across each stage is identical
and the compression process is polytropic. List and plot
the compressor work against the number of stages for
P1 100 kPa, T1 17 C, P2 800 kPa, and n 1.35 for air.
Based on this chart, can you justify using compressors with
more than 3 stages? cen54261_ch07.qxd 11/18/03 9:58 AM Page 349 349
CHAPTER 7 Design and Essay Problems
7–179 It is well known that the temperature of a gas rises
while it is compressed as a result of the energy input in the
form of compression work. At high compression ratios, the air
temperature may rise above the autoignition temperature of
some hydrocarbons, including some lubricating oil. Therefore,
the presence of some lubricating oil vapor in high-pressure air
raises the possibility of an explosion, creating a fire hazard.
The concentration of the oil within the compressor is usually
too low to create a real danger. However, the oil that collects on
the inner walls of exhaust piping of the compressor may cause
an explosion. Such explosions have largely been eliminated by
using the proper lubricating oils, carefully designing the equipment, intercooling between compressor stages, and keeping the
A compressor is to be designed for an industrial application in Los Angeles. I...
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This document was uploaded on 11/28/2012.
- Spring '09