PERFORMANCE CHARACTERISTICS OF A 6-POCKET HYBRID FLEXIBLE JOURNAL BEARING IN TURBULENT REGIME

Abstract

Multirecess hybrostatic/hybrid journal bearings are being used extensively and is the subject of increased attention now-a-days because of their applications in high speed turbomachinery, machine tools, aerospace industries, nuclear applications, medical equipment etc. The performance of hydrostatic/hybrid journal bearing system gets affected by number of parameters such as type of restrictor, bearing ` shell flexibility, number of pockets and turbulence etc. When the hydrostatic/hybrid journal bearing system is subjected to heavy loads, it results in high fluid film pressure in bearings and deforms the bearing shell. This in turn modifies the fluid film thickness profile and ultimately the bearing performance characteristics are altered. Quite ' often the. . bearings are required to operate at high speeds, while supporting heavy loads, and thus laminar flow assumption is no longer valid. Therefore, the bearing performance characteristics computed by considering the assumption that both bearing shell and journal are absolutely rigid and the bearing operates in laminar regime may not be more appropriate to use. Therefore, the effect of bearing shell flexibility along. with the consideration of • the turbulent flow condition in the analysis would be more relevant if the design of bearing is to be based on more realistic design data. Thus, in the present work - the performance characteristics of a six recess flexible hybrid journal bearing has been studied by considering turbulent -flow conditions using FEM with orifice restrictors. The turbulence effect is considered in terms of pressure and shear Reynolds number. The bearing shell flexibility has been taken into account by defining a parameter Cd. The effect of speed parameter, restrictor design- parameter is also