Modeling of gas leakage through compressor valves

• A model is proposed to quantify gas leakage in compressor valves.
• The model considers reed bending due to pressure load and slip flow regime.
• Estimates of leakage are obtained during the complete compression cycle.
• It is found that leakage may significantly reduce the compressor performance.

This paper describes a model developed to predict gas leakage in cases of incomplete sealing of the reed-type valves of small reciprocating compressors adopted for household refrigeration. The model assumes a one-dimensional formulation for the flow, considering the effects of viscous friction, slip-flow regime and compressibility. Reed bending into the port due to the pressure load is also taken into account to characterize the valve clearance. Computations are carried out during the compression cycle and the effect of leakage on both the isentropic and volumetric efficiencies is quantified for two operating conditions. It was found that leakage significantly reduces the compressor efficiency even for very small valve clearances and that leakage in the discharge valve is of greater importance than that in the suction valve.