Abstract
Efficiency is becoming a more and more fundamental aspect in many industrial sectors. A lot of effort is put, for example, by the automotive industry to design more efficient drivetrains, not only for economic reasons, but also for environmental reasons. The prediction of the efficiency and lubrication in gearboxes represents still a challenging task. Indeed, the mathematical models available in literature are based on empirical relations and dimensional analysis, and are accurate only as far as the actual geometry and operating conditions are very similar to the ones of the experimental tests. In this sense, a general approach capable of accurately predicting lubricant fluxes and power losses can lead to a significant advancement in the field. Thanks to recent developments in computers power, Computational Fluid Dynamics (CFD) has become an important tool for engineers to study the lubrication and efficiency of gears. However, the high computational resources necessary to run such simulations is still a concern. The implementation of a computationally efficient mesh-handling strategy is one of the main objectives of this thesis. The developed strategy has been applied to spur, helical and bevel gears, thus demonstrating its flexibility for various geometries, and to industrial cases as multi-stage and planetary gearboxes. The associated reduction of the computational effort allowed to simulate physical phenomena (as aeration and cavitation) and different types of lubricants (as oil and grease) without a significant impact on the computational costs. This analysis led to a better understanding of the physical phenomena occurring in the lubrication of gearboxes. Finally, a dedicated mesh motion strategy for the simulation of roller bearings was developed as the result of an industrial collaboration. The open source software OpenFOAM® was the main tool used to perform the analyses.