|为研究环下润滑结构内部油膜迁移及流动特性，针对轴心射流收油环采用VOF（Volume of fluid）方法开展了数值计算，获得了收油环端面油膜动态形成过程，在分析流场特征的基础上，讨论了收油环运转工况及结构参数对内部油膜形态、滑油体积分数、油膜速度和供油孔输油能力的影响规律。结果表明：收油环端面油膜呈圆盘状迁移，边缘破碎形成油滴、油带甩至侧壁面，在供油孔内以“月牙形”分布加速流动，收油环端面油膜厚度随主轴转速增大而减小，随喷嘴流量上升而增加；提高转速降低了供油孔内滑油含量，使孔内油膜加速流动，孔内滑油含量随喷嘴流量的上升而增大，随供油孔径的增加而下降；喷嘴流量与供油孔径的改变对孔内流速影响较小；增加孔径与提高收油环转速可加强供油孔输运能力，8 kr/min下提高喷嘴流量使无量纲输油量Cq平均降低了40.71%，提高孔径使Cq最大提高了57.14%，转速的增加使Cq平均增加25.87%。
|关键词: 环下润滑 收油环 轴心射流 两相流动特性 VOF方法
|Numerical simulation study of oil-air flow characteristics in axis jet oil receiving scoop
ZHU Zetao, LYU Yaguo, ZHU Pengfei, JIANG Le, LIU Zhenxia
School of Power and Energy，Northwestern Polytechnical University，Xi’an 710129，China
|In order to study the internal oil film migration and flowing characteristics of the under-race lubrication structure， the numerical calculations were carried out by using the VOF （volume of fluid） method for the axis jet oil receiving scoop and the dynamic formation process of oil film on the end face of the scoop is obtained. Based on the analysis of flow field characteristics， the effects of the scoop working conditions and structural parameters on the film shape， oil volume fraction， film velocity and the transportation capacity in the oil supply hole are discussed. Results show that， the oil film migrates in the form of disc at the end face of the scoop， and the oil droplets and the oil belts formed by the broken film edge are thrown to the side wall. The oil film accelerates in the form of crescent shape in the radial hole， and the film thickness on the end face of the scoop decreases with the increase of the rotational speed and increases with the increase of the nozzle oil flow. Increasing the rotational speed reduces the oil retention in the oil supply hole and accelerates the film flow in the hole， and the oil content in the hole ascends with the increase of nozzle flow and decreases with the increase of oil supply hole diameter. The change of nozzle oil flow and hole diameter has little effect on the flim flow velocity in the hole. Increasing the hole diameter and the rotational speed can improve the transportation capacity of the oil supply holes. Increasing the nozzle flow rate reduces the dimensionless oil flow Cq by 40.71% on average， and increasing the diameter increases Cq by 57.14% at most on 8 kr/min. The increase of rotation speed increases Cq by an average of 25.87%.
|Key words: Under-race lubrication Oil receiving scoop Axis jet Two-phase flow characteristics VOF method