📊

Volumetric Efficiency Calculator

Clearance Effects on Cylinder Capacity

Volumetric Efficiency
Calculate the ratio of actual gas displaced to cylinder swept volume. VE is affected by clearance volume, compression ratio, and gas compressibility.

Clearance Volume

%
Typical: 8-30% normal, 40-200% pipeline cylinders

Operating Conditions

psia
psia
:1

Gas Properties

-
Natural gas: 1.24-1.34

VE Formula

Method Formula
Ideal GasVE = 1 - C × (r1/k - 1)
With Z CorrectionVE = 1 - C × [(Zs/Zd) × r1/k - 1]

Where: C = clearance fraction, r = compression ratio, k = Cp/Cv

VE Guidelines

Excellent: VE > 85% - Low clearance, low ratio
Good: VE 70-85% - Typical operating range
Fair: VE 50-70% - High ratio or clearance
Poor: VE < 50% - May need staging

Frequently Asked Questions

What is volumetric efficiency in a reciprocating compressor?

Volumetric efficiency is the ratio of actual gas volume delivered to the swept volume of the cylinder, affected by clearance volume, compression ratio, and gas properties.

What factors affect reciprocating compressor volumetric efficiency?

Key factors include clearance volume, compression ratio, and gas properties such as the specific heat ratio (k value).

How do unloaders affect compressor capacity?

Unloaders reduce compressor capacity by deactivating cylinder ends, allowing operators to predict capacity changes at different operating conditions.