Evaluating simulation techniques for lubricant distribution in gearboxes

TL;DR

This paper compares different numerical simulation methods for lubricant distribution in gearboxes, evaluating their accuracy and efficiency, and extends the analysis to grease lubrication under various operational conditions.

Contribution

It provides a comprehensive comparison of Eulerian and Lagrangian solvers for gearbox lubrication, including validation with experimental data and analysis of grease distribution factors.

Findings

OpenFOAM and Ansys-Fluent match experimental data but are computationally intensive.

PreonLab offers good qualitative results but less accurate quantitatively.

Filling volume and gear speed significantly influence grease deposition.

Abstract

Efficient lubrication is crucial for the performance and durability of high-speed gearboxes, particularly under varying load conditions. Excess lubrication leads to increased churning losses, while insufficient lubrication accelerates wear on contact surfaces. Due to the high rotational speeds involved, direct experimental visualization of lubricant distribution within gearboxes is challenging, making numerical simulations indispensable. Although various modelling approaches exist, a direct comparison that jointly evaluates accuracy and computational efficiency is missing. Furthermore, studies on the computational modelling of highly viscous lubricants such as grease in gearboxes are limited. This study addresses these gaps by comparing two mesh-based Eulerian solvers (OpenFOAM and Ansys-Fluent) and two Lagrangian particle-based solvers (PreonLab and MESHFREE) for oil distribution in gearboxes. Two benchmark cases are considered: one for qualitative assessment and another for quantitative evaluation. OpenFOAM and Ansys-Fluent show good agreement with the experiment data in selected cases, but incur a significant computational cost. PreonLab performs well qualitatively, yet exhibits greater deviation in quantitative predictions. These comparisons provide information for selecting the suitable solver according to specific simulation requirements. Furthermore, the study extends to grease distribution by first validating the solver and then investigating the influence of filling volume and gear speed on the amount of grease deposited on gears. The benchmark cases presented provide a reference framework for evaluating additional solvers in future gearbox lubrication studies.