考虑油气传热传质耦合的轴承腔内壁油膜运动研究

Motion of Wall Oil Film with Consideration of Oil-Gas Coupled Heat and Mass Transfer in Bearing Chamber

关键词:  轴承腔  油气耦合  传热传质  运动特性  油膜厚度

Key words:  Bearing chamber  Oil-gas coupling  Heat and mass transfer  Motion characteristics  Oil film thickness

摘要:

为研究航空发动机轴承腔油气两相流动及内壁面油膜运动特性，建立了腔内油滴-空气双向耦合数学模型和内壁面油膜传热传质运动模型，并对油气流场及不同供油流量下油膜的流动进行计算，获得腔内两相流场特性及内壁面油膜厚度、周向速度分布。结果表明:在所计算工况中，双向耦合计算流场与单向计算结果至少相差10%，因而不可忽略油滴对空气流动的影响；腔内滑油蒸汽质量分数低于0.05%，则空气-油滴之间粘性力产生的拖曳作用是影响流场的主要因素；随着供油流量的增加，油膜厚度及周向速度都呈增加趋势，但与滑油流量的增幅并不成正比。与国外试验数据的对比证明所建数学模型合理且有效。

Abstract:

In order to study the oil/gas two-phase flow and motion characteristics of wall film in the aero-engine bearing chamber，the oil /air two-way coupled mathematical model and the oil film heat and mass transfer movement model were established. The oil/gas two-phase flow field and the motion characteristics of wall film with the oil flow rate were calculated，and the flow field characteristics，the thickness and circumferential velocity distribution of wall film were obtained. The results here show that，the flow field difference between two-way and one-way coupled calculation is at least 10%，and therefore the effects of oil droplets on air flow cannot be ignored in the calculation of two-phase flow. The oil vapor mass fraction in the bearing chamber is less than 0.05%，which indicates that the drag effect produced by viscous forces between the oil droplets and air is the main factor affecting the flow field. Both the oil film thickness and circumferential velocity show a trend of increasing with the increasing of the lubricating oil flow rate，but the increasing is not proportional to the increase amplitude of oil flow rate. Besides，the verification with the experimental data proves that the mathematical analysis model here is reasonable and effective.