Centrifugal Compressors: A Basic Guide
Providing an up-to-date reference in the field of centrifugal compressors, this comprehensive book covers all major aspects of design, operation, and maintenance.
TABLE OF CONTENTS Centrifugal Compressors: A Basic Guide
Chapter 6: Off-Design Performance Characteristics
COMPRESSOR PERFORMANCE
The performance of a centrifugal compressor is dependent on many factors, the most important being the composition and the physical and chemical characteristics of the gas it is compressing. Thus, the characteristics of the compressor must be corrected for the characteristics of the gas, to be evaluated at off-design considerations.
PERFORMANCE CALCULATIONS
The performance calculations are based on the basic equations, as outlined in Chapter 2. To properly evaluate the trend of values, absolute values must be corrected to some conditions such as design conditions and, in the case of off-design operational conditions, some values must be transposed to design conditions. The following are some of the governing equations for correcting major performance parameters:
CORRECTED COMPRESSOR MASS FLOW
| (6-1) |  |
where M corr and M act is the corrected and actual mass flow, and P ref, T ref, MW ref are the Pressure, Temperature, and Molecular Weight at reference conditions, such as design inlet conditions.
CORRECTED COMPRESSOR VOLUME FLOW
| (6-2) |  |
where Q corr and Q act is the compressor's corrected and actual Volume flows.
CORRECTED (AERODYNAMIC) SPEED
| (6-3) |  |
where N corr and N act are the compressor's corrected and actual speed
CORRECTED POWER
| (6-4) |  |
where HP corr and HP act is the compressor's corrected and actual required power
CORRECTED HEAD (ADIABATIC OR POLYTROPIC)
| (6-5) |  |
where H corr and H act is the compressor's corrected and actual Head produced.
CORRECTED PRESSURE
| (6-6) |  |
where P corr and
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