Numerical Modeling of Oil-Jet Lubrication for Spur Gears using Smoothed Particle Hydrodynamics

Understanding and optimizing the lubrication and cooling in aero engine gearbox applications is crucial for a reliable and efficient sub-system design of future aircraft engines. Due to the complex design of gearboxes with its various rotating parts, space and access for experimental investigations are severely limited. Thus, suitable numerical methods need to be developed in order to thoroughly investigate the evolving oil-air two-phase flow in the vicinity of the gear teeth. In this paper, the impingement of a single oil-jet on a single rotating spur gear was analyzed using the Smoothed Particle Hydrodynamics (SPH) method. The study was conducted with a simplified 2D setup under typical operating conditions met in reduction gear units of novel large civil aircraft engines. Results of the predicted oil-air two-phase flow are presented and compared to conventional Volume-of-Fluid (VOF) simulations. The wetting behavior and the impingement depth of the oil-jet between the gear teeth are investigated for varying oil-jet velocities and rotational speeds. In order to capture three-dimensional flow effects, a 3D setup and preliminary results are presented.