compressor, friction, minimum oil film thickness, pressure distribution, parametric study
Friction loss has a significant impact on the performance of a reciprocating compressor. Piston-cylinder friction is a major contributor compared to the other contributors like thrust bearing, piston pin and crank. In the present work,the piston–cylinder interaction inside a small hermetic compressor is modeled using the Reynolds equation which is solved using finite difference method. The model provides key compressor design parameters such as minimum oil film thickness, oil pressure distribution between piston-cylinder, normal forces and friction power loss. The model is validated against data from published literature. Using the above formulation, different concepts have been studied & compared against their friction loss characteristics. These include variable speed versus variable displacement for capacity control, piston-cylinder clearance for blow-by, cold start (high viscosity oil due to low temperature), lubricating fluids, viz. POE versus gas bearing.