基于多节点热网络法的航空发动机主轴轴承温度场分析

Steady Thermal Analysis of Main-Shaft RollerBearing for Aero-Engine Based on Multi-NodesThermal Network Methods

关键词:  航空发动机  主轴轴承  热网络法  节点划分  传热扩散热阻

Key words:  Aero-engine  Main-shaft bearing  Thermal network  Multi-nodes  Thermal spreading resistance

摘要:

航空发动机主轴轴承温度场分析是发动机润滑系统热分析的关键。针对传统简单节点热网络法中轴承温度节点设置过于简化、人为设置轴承生热分配比例等问题，提出改进的多节点热网络法。基于Hertz热扩散理论，将轴承三元件分别划分为接触表面与主体两个节点，并以Hertz扩散热阻连接；轴承接触区设置油膜节点，加载轴承生热载荷，节点与轴承接触面之间通过油膜热阻连接；构建多节点轴承热网络模型，获得轴承内部更细致的温度场分布。研究表明，轴承表面温度显著高于其内部主体结构温度，而接触区对应的两个接触面之间也存在明显的温度差异，使用本文建立的多节点热网络法对滑油出口温度的计算误差不超过7%。

Abstract:

A clear thermal statement analysis of main-shaft roller bearings is key element to better understand and optimize the oil system design. For the traditional thermal network， the bearing is simply replaced by three nodes and its heat generation has to be loaded artificially. In this article， an improved multi-nodes thermal network method is proposed. Each bearing element is divided to two nodes， for the surface and the bulk respectively. A Hertz spreading resistance is then accounted between them. All heat generation of the bearing is loaded to the oil film center， which is set as another node in the contact zone. Results show that the bearing element surface is much hotter than its bulk， and there is temperature difference between two corresponding surfaces in the contact zone. Based on the thermal network method， the error of predicted oil outlet temperature could be less than 7%.