For the purpose of analyzing the characteristics of the internal flow field of middle reducer with splash lubrication in a certain helicopter

based on the computational fluid dynamics (CFD) method

a numerical simulation model for the splash lubrication of middle reducer

including gear box housing

spiral bevel gear and oil guide device

was established by using the volume of fluid (VOF) multi-phase flow model and the turbulence model. With these models

the flow field characteristics of splash lubrication were obtained

and the transient flow field of lubricating oil in reducer was visualized; the influence of gear speed and oil immersion depth on the flow of lubricating oil in key positions was analyzed. Results showed that the oil flow in gear meshing zone was positively correlated with the gear speed and the depth of oil immersion. The oil flow in the oil guide pipe was related to the oil saturation value of the oil guide device. When the oil quantity was greater than this value

the oil flow in the oil guide pipe increased with the increase of the gear speed

and remained constant with the increase of the oil immersion depth. A splash lubrication test system of spiral bevel gearbox was set up

and results of oil flow tests of round hole in the process of splash lubrication were compared with the corresponding simulation results

the maximum error of simulation results relative to experiment was 9.5%

verifying the correctness of the simulation method.