Experiments and Lattice-Boltzmann Simulation of Flow in a Vertically Aligned Gearbox

This paper presents a study of the oil flow in a vertically arranged FZG gearbox. The splash and churning losses are experimentally evaluated using measurements of the resistance torque. Using high-speed imaging, the instantaneous oil splashing inside the gearbox is also presented and compared to computational fluid dynamics (CFD) results from the lattice-Boltzmann method with the volume of fluid model, instead of the traditional finite volume method. Four different configurations, including a spur gear based on the standard FZG geometry and a disc pair wheel-pinion with the same tip diameters of the standard geometries, are used. The experiments cover a range from 500 to 3000 rpm and three oil levels are studied. For the CFD simulations, the same oil levels and rotational speeds are used. The experimental results indicate torque differences depending on the oil level and the configuration. The splashing pattern is also different from the standard horizontal FZG case, which is typically studied in the literature. On the other hand, the CFD simulations and flow visualization experiments are in relative agreement with one another. The similarities and differences in the torque values for the different configurations and the splashing pattern for both experiments and CFD simulations are analyzed and discussed.