Optimum Design of Dynamically-Loaded Journal Bearing with R600a Refrigerant Application

Present study is undertaken to optimize the lubrication reliability and frictional loss of the dynamically-loaded jownal bearing with R600a refrigerant application. A mathematical model is developed for analyzing the dynamics of the journal bearing system with the mobility method. It takes into account the effects of the refrigerant species, aspect ratio, clearance ratio and surface roughness. A corresponding computer program is described which enables to obtain the minllnum film thickness and frictional loss. Design optimization is graphically performed by parametric studies of the aspect ratio and clearance ratio. C bearing clearance e: eccentricity velocity L: bearing length NOMENCLATURE D: bearing diameter F. bearing force M: journal mobility e: eccentricity h min: minimum film thickness R: bearing radius Rq: rms surface roughness p: lubricant viscosity e: eccentricity ratio m: mean angular velocity .Am: relative angular velocity INTRODUCTION The recent development in alternative refrigerant compressor has made clear the demand for the optimum design of the bearing system The optimization problem of bearing system makes compromise technique between the lubrication reliability and frictional loss desirable. In this work, the dynamics of journal bearing is therefore calculated by the mobility method considering the efficiency of optimization process. In a design example, the connecting-rod journal bearing at a reciprocating compressor with the swept volume 8.7 cm is presented. We refers simulation results of the same compressor for the cylinder pressure datum with refrigerant. The minimum film thickness and the frictional loss as performance parameter are successively studied with design parameter such as -the aspect ratio, clearance ratio, surface roughness and refrigerant species. Design optimization is graphically perlormed by parametric studies of the bearing aspect ratio and clearance ratio. MOBILITY METHOD The Basic Idea of The Mobility Method