GPSA Section 13 and API 617
Understand polytropic compression, head equations, and the relationship between pressure ratio and head
Polytropic head is the energy per unit mass imparted to the gas by the compressor, calculated from pressure ratio, gas properties, and compressibility factors.
You need pressure ratio, gas molecular weight, compressibility factors, suction temperature, and polytropic efficiency.
It follows GPSA Section 13 and API 617 methods for centrifugal compressor polytropic head calculation.