减速器内部金属屑运动仿真分析

为掌握因轴承磨损产生的金属屑在直升机中间减速器内部流场中的运动状态，针对其固-液-气三相流特征建立了金属屑颗粒受力平衡方程和多相流模型-离散相模型（VOF-DPM）耦合的CFD仿真模型。基于离散相运动方程编程计算及采用CFD仿真分析方法获得了减速器内部颗粒的运动轨迹、运动速度，并据此对比验证了VOF-DPM耦合模型的正确性；利用CFD仿真分析了颗粒在流体中运动时各种附加力对颗粒运动轨迹的影响，探究连续相空气、滑油与离散相颗粒三者之间的相互作用机理。结果表明：连续相和离散相耦合作用对颗粒运动的影响较小，轨迹误差约5%、速度误差约3%，可忽略不计；虚质量力、压力梯度力和Magnus升力对颗粒运动轨迹影响较大，Saffman升力对颗粒运动轨迹影响较小，而热泳力与布朗力不适用于直升机中间减速器固-液-气三相流情形。

Motion Simulation Analysis of Metal Chip Inside Reduction Gearbox

In order to grasp the motion state of metal chips due to wear of bearing in the internal flow field of the helicopter Intermedi-ate reduction gearbox, aiming at the characteristics of solid-liquid-gas three-phase flow, the force balance equation of metal chip particlesand VOF-DPM coupled CFD simulation model were established. Based on the discrete phase motion equation programming calculationand CFD simulation method, the motion trajectories and velocities of the particles inside the reduction gearbox were obtained, and the accu-racy of the VOF-DPM coupling model was verified by comparison; The influences of various additional forces on the motion trajectories ofparticles were analyzed by CFD simulation to explore the interaction mechanism between continuous phase air, oil and discrete phase parti-cles. The results show that the coupling of continuous and discrete phases has a small impact on particle motion, with a trajectory error ofabout 5% and a velocity error of about 3%, which can be ignored; Virtual mass force, pressure gradient force, and Magnus lift have signifi-cant impacts on the particle motion trajectory, while Saffman lift has a relatively small impact on the particle motion trajectory, however,Thermophoretic and Brownian force do not apply to the solid-liquid-gas three-phase flow of the helicopter Intermediate gearbox.