Numerical and Experimental Investigation of Oil-Guiding Splash Lubrication in Light Helicopter’s Reducers

Abstract

Limited by the space and weight of the reducer, it is difficult to use traditional oil-jet lubrication and splash lubrication for a light helicopter, so an oil-guiding splash lubrication method is adopted as a research object in this paper. Firstly, the lubrication performance of the oil-guiding cylinder in the main reducer under different rotating speeds, oil levels, and flight attitudes is investigated based on the computational fluid dynamics (CFD) method. Then, a specific test rig is developed, and lubrication tests are carried out to verify the feasibility and correctness of the simulation. These results show that oil level, rotating speed, and flight attitude have a great influence on splash lubrication performance.

Performance of a New Aeronautic Oil-Guiding Splash Lubrication System

“…By leveraging the oil-guiding channel, the oil mass transferred from the gear surface into the channel increases, and then the oil volume collected through the oil-collecting pipe also increases. Specifically, at the rotating speed of 400 rpm, the oil flow rate with the oil-guiding channel in this study exceeds 2.5 mL/s, far more than the experimental data of 0.0017 mL/s, conducted by Yin et al [27,28]. At the rotating speed of 660 rpm, the oil flow rate with the oil-guiding channel exceeds 22.6 mL/s, much greater than the experimental data of 0.034 mL/s, performed by Yin et al [27,28].…”

“…Specifically, at the rotating speed of 400 rpm, the oil flow rate with the oil-guiding channel in this study exceeds 2.5 mL/s, far more than the experimental data of 0.0017 mL/s, conducted by Yin et al [27,28]. At the rotating speed of 660 rpm, the oil flow rate with the oil-guiding channel exceeds 22.6 mL/s, much greater than the experimental data of 0.034 mL/s, performed by Yin et al [27,28]. This shows the oil flow rate is increased by about three orders of magnitude, benefiting from the oil-guiding channel.…”

“…On the other hand, the axis of the driven gear is perpendicular to the static liquid surface of the oil bath, and it is not convenient for traditional splash lubrication. Recently, Yin et al [27,28] proposed a special oil-guiding splash lubrication method and investigated the lubrication performance of three different oil-guiding cylinders under different working conditions. However, the clutch and bearings of the driving shaft also need to be lubricated by the oil from the bottom oil bath.…”

CFD Investigation into Flow Characteristics of a Special Splash Lubrication in Light Helicopters

“…Kolekar et al [17] developed a specialized test bench comprising a cylindrical box and a single spur gear for the purpose of determining the effect of lubricating oil qualities on churning power loss. Yin et al [18,19] studied the effect of various types of oil-guiding cylinder structures on the splash lubrication effectiveness in a light helicopter gearbox employing a CFD model, and the numerical results accorded well with the experimental findings. Peng et al [20] developed a CFD model for simulating lubrication flow within a vehicle axle housing.…”