Minimum Volumetric Efficiency
Volumetric Efficiency (VE)
is the ratio of the actual delivered gas volume to the swept volume of
the cylinder. For additional information refer to the compressor
theory
The minimum allowable suction
volumetric efficiency for any cylinder end at a proposed operating point
is 15% and for any design point is 30%. These limits are set due to the
variation in factors used to calculate the volumetric efficiency. The
factors used include internal compression ratio (calculated vs. actual
piping pressure losses, valve losses, gas pressure pulsations), gas characteristics
(ratio of specific heats or k value, gas compressibility), compressor
valve springing and cylinder clearance volume.
Low volumetric efficiencies will
result in higher than expected discharge temperatures, higher than expected
horsepower per million and lower than expected capacity.
Discharge volumetric efficiency
must be measured in time rather than percent. Refer
to Discharge Event for information
and limits on discharge volumetric efficiencies.
Ariel
Corporation Application Manual
18-Sep-96