CENTRIFUGAL COMPRESSOR

Centrifugal Compressor calculates discharge conditions, polytropic head and power for a centrifugal machine on a real-fluid basis, from suction and discharge pressure, suction temperature, composition and mass flow rate.

Capabilities

• Discharge temperature and polytropic head.
• Gas power and driver shaft power, reported separately, with mechanical efficiency applied.
• Discharge dew point and superheat margin at discharge pressure.
• Suction and discharge compressibility factors, densities and phase states, and the gas’s molar mass.
• Effective polytropic exponent derived from the result.
• Flag where discharge temperature exceeds a commonly referenced guidance value for seal and lubricant life.
• Liquid or two-phase suction detected and held, with the reason stated.
• Exportable PDF report.

Why the results hold up

Discharge temperature and head come from an energy balance integrated along the real-fluid compression path on the Peng-Robinson equation of state. The calculation does not use an ideal-gas closed-form relation, which can overstate discharge temperature at higher pressure ratios. Compressibility, density and phase state are evaluated at both suction and discharge for the actual composition. If the stepwise calculation cannot be resolved for the entered conditions, the module withholds the result and gives the reason rather than substituting an approximation.

Scope

Single-stage, steady operating point at the entered polytropic efficiency. No performance map is used, so surge, stall and a blocked discharge are outside the calculation, as are mechanical limits, seal and lubricant temperature limits, and interstage cooling. The calculation follows a Peng-Robinson polytropic method rather than a compressor performance-test standard.