Fluid and Thermal Dynamics Simulation of Spur Gears under Steady State Operation

A multi-scale computational model has been developed for application to the micro- and macro-scale thermo-fluid-dynamics in high speed gear systems. At the micro-space/time-scale, a model of gear mesh lubrication film transport and heating is presented based on elastohydrodynamic lubrication (EHL) tribology and mesh kinematics. At the macro-space/time-scale, computational fluid dynamics (CFD) tools are used to resolve the time-dependent conduction and convection (windage) processes within the gears and gearbox. Scale-spanning averaging procedures were developed for coupling the instantaneous meshing and macro scale physics. The overall method is presented and applied to an equilibrium mist-lubricated gearbox configuration tested at the NASA Glenn Research Center.