Evaluate compressor performance for gas systems with precision calculations
Calculate key parameters for centrifugal, reciprocating, axial, and screw compressors
Polytropic efficiency (ηp) is the ratio of ideal polytropic work to actual work. It accounts for
heat transfer during compression and is calculated as:
ηp = [ln(P2/P1)] / [ln(T2/T1)] × (γ-1)/γ
where γ is the ratio of specific heats (Cp/Cv). Polytropic efficiency is typically 70-85% for centrifugal compressors.
Adiabatic (isentropic) head (Had) is the work required to compress gas isentropically:
Had = ZavgRT1(γ/(γ-1))[(P2/P1)(γ-1)/γ - 1]
where Zavg is average compressibility, R is gas constant, and T1 is inlet temperature.
Power required (P) depends on mass flow (ṁ), head (H), and efficiency (η):
P = (ṁ × H) / (η × 1000) (in kW)
For multi-stage compressors, power is summed across all stages plus mechanical losses (typically 2-5%).
Actual motor power includes an additional safety margin (typically 10-15%).
