Abstract:
Operating temperatures in a drive system gearbox are impacted by multiple factors like mechanical power, operating environment, geometrical design and lubricant properties. Cooling and lubrication performance is critical to operation and durability. Oil properties like viscosity, specific gravity and thermal conductivity play a major role in determining the quality of lubrication inside the gearbox and the efficiency of waste heat exchange. The interaction of lubricating oil with gears and surrounding structures is however a complex multi-physical problem. Complete coupled modeling of the various micro and macro physical phenomena at play inside the gearbox is challenging and computationally expensive. For this reason, manufacturers have traditionally relied on experimental evaluations of prototype gear boxes for product development. A more desirable approach is to develop a full simulation capability to aid the design process and minimize development risk. To this end, a CFD methodology for the prediction of lubricating oil flow and heat transfer is developed. The methodology is applied and validated with the "splash lubricated" accessory gearbox of the Bell 525.