Page 129 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Compressor Best Practices Be st Practice 3.1

Fig 3.1.12 Typical multi-stage refrigeration compressor

As we will see, there are basically two velocities which
determine the performance of a dynamic compressor. Both
of these occur at the exit of the moving blade. They are tip
speed (the product of blade tip diameter and RPM) and
relative velocity (velocity of the gas between two blades).
The curve of a centrifugal compressor is significantly differ-
ent from that of a positive displacement compressor. The

Fig 3.1.13 Typical multi-stage, radially-split centrifugal compressor Fig 3.1.14 Typical integrally-geared, centrifugal compressor
(Courtesy of Mannesmann Demag) (Courtesy of Mannesmann Demag)

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