A New Integrated Approach for the Prediction of the Load Independent Power Losses of Gears: Development of a Mesh-Handling Algorithm to Reduce the CFD Simulation Time

Abstract

To improve the efficiency of geared transmissions, prediction models are required. Literature provides only simplified models that often do not take into account the influence of many parameters on the power losses. Recently some works based on CFD simulations have been presented. The drawback of this technique is the time demand needed for the computation. In this work a less time-consuming numerical calculation method based on some specific mesh-handling techniques was extensively applied. With this approach the windage phenomena were simulated and compared with experimental data in terms of power loss. The comparison shows the capability of the numerical approach to capture the phenomena that can be observed experimentally. The powerful capabilities of this approach in terms of both prediction accuracy and computational effort efficiency make it a potential tool for an advanced design of gearboxes as well as a powerful tool for further comprehension of the physics behind the gearbox lubrication.

Lubrication of Gearboxes: CFD Analysis of a Cycloidal Gear Set

“…Small cells were inevitably produced and this causes a significant increment in the computational effort required, not so much for the increased number of elements, but for the need, in order to ensure the stability of the solution, to reduce drastically the time step (to keep the Co number equal to 1). The authors have shown how, with the so called global remeshing approach (GRA) [45], it is possible to have a much higher control of the grid parameters, ensuring huge time savings for the computation thanks to the bigger possible time steps.…”

Analysis of an Automatic Valve Geometry for Concrete and Drilling Mud Pumps to Avoid Cavitation: Non-Newtonian CFD Modelling

“…In presence of small gaps [18], and specifically between the valve and the valve seat, the size of the mesh results significantly reduced and the computational time increases significantly. Some specific techniques can be applied when the viscous contribution can be neglected [19], [20], but this is not the case. Despite of the symmetry, more than 2 million cells are required in order to properly discretize the domain.…”

Effect of the static pressure on the power dissipation of gearboxes

“…The amount of lubricant that ensures the proper lubrication of all the components has for a long time been selected empirically or by trial and error procedures, with the goal of minimizing the power losses . In recent years, the authors have demonstrated the effectiveness of the numerical computational fluid dynamic (CFD) approach in order to improve the efficiency of gearboxes, thanks to the possibility of optimizing the internal geometry and the lubricant level, on the basis of quantitative data and not only of experience …”

“…12 In recent years, the authors have demonstrated the effectiveness of the numerical computational fluid dynamic (CFD) approach in order to improve the efficiency of gearboxes, thanks to the possibility of optimizing the internal geometry and the lubricant level, on the basis of quantitative data and not only of experience. 13 In this paper, a recently developed simulation tool capable to take into account the effect of cavitation 14 is systematically applied to study the effect of the static depressurization on the load independent power losses of gears. Different static pressures and rotational speeds have considered.…”