Numerical Investigation And Application Of Three-dimensional Lubrication Performances Of Journal Bearings In Rotary Compressor

Bearing-Rotor System is the key moving parts in Rotary Compressor. The lubricationperformance of the system directly affects the overall performance of the compressor.Numerical investigation of three-dimensional lubrication performances of journal bearingsplays a very important part in reducing the radial bearing wear, improving compressorefficiency and machine reliability, reducing noise and vibration, extended service life.Based on the rotary compressor, the bearing rotor system dynamics analysis, andobtain load in a work cycle of the compressor main or sub bearing. Based the basic theoryof tribology, the model of journal bearing hydrodynamic lubrication numerical analysis iscreated. For a more realistic simulation, the factors that have effects on the lubricationperformances of journal bearing are considered, such as surface roughness and the effectsof temperature and pressure on the density and viscosity of oil. The oil film thickness andfriction power are determined. The lubrication performances of journal bearing areanalyzed and compared in the conditions of radius of journal bearing, bearing clearance,bearing width, crankshaft speed and lubricant oil pressure. The three-dimensional EHLmodel has been built, which coupled the three-dimensional HL equation and surfaceelastic distortion equation of lubrication surfaces. The lubrication performances of journalbearing are analyzed and compared in the conditions of bearing structure and operationconditions. In addition, based on the hydrodynamic lubrication model, the orthogonalexperimental design is used to optimize the parameters of the bearing structure. This paperselects the radius of the crankshaft, bearing width and bearing clearance as calculatefactors, selects the friction power and minimum film thickness as evaluation criterion.The results show that: the main bearing friction power accounts for a large proportionof the total friction power, reducing the main bearings friction power is the main way toreduce the total friction power. There are many ways to reduce friction power, such asincreasing bearing clearance, reducing the radius and the width of the bearing. Increasingthe width and the radius of the bearing can increase the contact area, which can reduce theoil film pressure and increase minimum film thickness, so that the bearing lubrication ishydrodynamic lubrication. To design bearing parameter, the minimum film thickness andbearing friction power should be considered. The best way of design bearing is to ensureminimum film thickness is large enough so that the lubrication is hydrodynamiclubrication, and then select the friction power as a small one.