Air barrier effect in out of mesh jet lubrication of ultra-high speed spur gears

Purpose-This paper aims to reveal the mechanism of air barrier effect in jet lubrication and to figure out the influence of gear parameters and conditions on air barrier, thus providing guidance to the design of jet lubrication in ultra-high speed gear cooling system. Design/methodology/approach-The computational fluid dynamics method is used to calculate the flow and pressure of ultra-high speed gears. The flow and pressure distributions are obtained under different gear parameters and working conditions, so their variations are obtained. A multiphase flow model is established to simulate the flow regime of oil jet to ultra-high speed gears. Simple experiments are carried out to observe the air barrier effect of high-speed gears. Findings-Air barrier effect exists in the jet lubrication of ultra-high speed spur gears, which could prevent oil jet to reach on the gear surfaces. The results show that the generated pressure has positive relations with gear speed, module and width; however, as the increasing of gear width, their marginal contribution to pressure is decreasing. The computational results coincide well with the experimental results. Originality/value-The research presented here proposed the air barrier effect of ultra-high speed gears for the first time. It also leads to a design reference guideline that could be used in jet lubrication of ultra-high speed gears, thus preventing lubrication and cooling failures.