Numerical Visualization of Grease Flow in a Gearbox

Abstract

Lubricating greases are widely used in e.g. open gear drives and gearboxes with difficult sealing conditions. The efficiency and heat balance of grease-lubricated gearboxes depend strongly on the lubrication mechanisms channeling and circulating, for which the grease flow is causal. The computational fluid dynamics opens up the possibility to visualize and understand the grease flow in gearboxes in more detail. In this study, a single-stage gearbox lubricated with an NLGI 1-2 grease was modeled by the finite-volume method to numerically investigate the fluid flow. Results show that the rotating gears influence the grease sump only locally around the gears. For a low grease fill volume, the rotation of the gears is widely separated from the grease sump. For a high grease fill volume, a pronounced gear-grease interaction results in a circulating grease flow around the gears. The simulated grease distributions show good accordance with high-speed camera recordings.

Review of Wind Power Bearing Wear Analysis and Intelligent Lubrication Method Research

“…Therefore, it is possible to analyze the bearing wear and monitor the change of the bearing lubricant film thickness through the electric potential, which provides a new method for monitoring the bearing lubrication status. For visual analysis of grease flow, Liu et al [216] modeled and analyzed a greaselubricated gearbox utilizing the finite volume method to numerically study the fluid flow of grease. The simulation results show that when the gear rotates, there is only a localized effect on the bottom of the oil shell around the gear; when the grease filling level is low, there is a significant separation between the gear rotation and the grease; and when the grease fill level is high, there is a significant interaction between the gear and the grease, The lubrication status of the bearing directly reflects the health of the bearing; the scientific research and technical personnel and the industrial and commercial sectors have long been in the bearing lubrication status monitoring much research, but still need to be further improved and accurate.…”

Lubrication Reliability and Oil Churning Loss of Differential Gear Trains in a Mechanical-Hydraulic Coupling Mechanism

“…For planet gears, when the temperature is low, the power losses decrease with the temperature at a high rate. Liu et al [20,21,22] built an FZG gear test bed and established a 3D simulation model considering two-phase flow. By comparing the simulation results with the test results, it was found that they have good consistency.…”