Churning power loss of the intermediate gearbox in a helicopter under splash lubrication

Abstract

Based on computational fluid dynamics, a two-phase flow model was established to calculate the churning power loss of the spiral bevel gears under splash lubrication. The error between the simulation results and experiment results is only 7.04%. Taking a certain helicopter as an example, the churning power loss of the intermediate gearbox is ∼2.6051 kW, accounting for ∼1.93% of the input power. Besides, the motion mechanisms of free flow, ejection flow and splashing flow of the spiral bevel gear were investigated. The influences of the rotational speed and oil immersion depth on the churning power loss were analysed. The rotational speed and oil immersion depth of the intermediate gearbox should be in the range of 3000–5000 r/min and 17–26 mm, respectively, which can ensure sufficient lubrication and low churning power loss.

Research on Splash Lubrication Characteristics of a Spiral Bevel Gearbox Based on the MPS Method

“…They found that the structural aperture of the oil guide device and the radius of the oil duct have important influences on the oil supply of the bearing, but have minor effects on the churning loss and the lubrication of the gear meshing zone. Lu et al [32] established a CFD model of oil-air two-phase flow for the intermediate gearbox used in helicopters. According to the oil flow characteristics, the lubricating oil stirred by the gear is divided into free flow, jet flow and splash flow.…”

“…Although the authors of the above literature have carried out relevant research on the lubrication characteristics of the splash-lubricated bevel gear transmission system, the numerical model used for research is quite different from the actual model. Compared with the gears in the engineering model, the gears in References [30][31][32][33][34][35][36][37] are all reduced, and therefore cannot reflect the real tooth surface shapes and meshing relationships. In addition, in order to reduce the pre-processing of the model and the number of grids used for numerical calculation, a box with a relatively simple shape is necessary.…”

Performance of a New Aeronautic Oil-Guiding Splash Lubrication System

“…As for the complex spiral bevel gears, Hu et al [8,9] and Jiang et al [10] quantitatively analyzed the influence of rotating speed, oil guide device, and dynamic attitudes on the churning losses of spiral bevel gears in the intermediate or tail gearbox of a helicopter using the CFD method. Lu et al [11] also investigated the effects of the rotating speed and oil immersion depth of spiral bevel gears in the intermediate gearbox, and further recommended the speed and depth range on the basis of the balance between sufficient lubrication and low churning losses. Using the smoothed particle hydrodynamics method, a similar study was also conducted by Legrady et al [12].…”

Application of the GRAMC mesh-handling strategy for the simulation of dip and injection lubrication in gearboxes

“…Tetrahedral meshes are characterized by higher generation times with respect to prismatic or hexahedral elements. Single rotating helical gears [11] and spiral bevel gears [12] have been already simulated by the authors, while the virtual modelling of mating gears has been approached with mesh [13][14][15][16][17][18][19][20] and meshless methods [21][22][23][24][25][26] in commercial software. Works based on a general procedure in open-source software are still lacking in the literature.…”