Gearbox lubrication CFD (Lattice Boltzmann)

Project · Project 42

A CFD study of oil–air multiphase flow in a gearbox using a GPU-accelerated Lattice Boltzmann Method (LBM) solver, analysing lubricant distribution and torque losses under realistic operating conditions.

Method

The model captured the fluid interaction between rotating gears at a transmission ratio of 1.54:1, evaluating oil impregnation, wetted surface area and the resulting torque losses. A mesh sensitivity study compared a coarse case of 40k elements against a fine case of 324k elements.

Volume fraction fields for coarse and fine lattice resolutions/assets/img/projects/gearbox-vof.png

Fig. 1 — Oil–air distribution, coarse (02:09) vs fine (20:24) calculation time.

Results

Wetted surface area settled at 32.5% for the driving gear and 56% for the driven gear, with quasi-periodic torque losses on both.

Torque losses and wetted area for driving and driven gears/assets/img/projects/gearbox-torque.png

Fig. 2 — Torque losses and wetted area results.

The mesh sensitivity study identified significant discrepancies between the two resolutions, highlighting the need for further lattice refinement and reduced time steps to achieve convergence — the honest conclusion being that the study establishes the method and bounds the problem rather than delivering a converged answer.

Read the paper →