基于有限单元热网络法的航空发动机主轴轴承热分析

Thermal Analysis of Main Shaft Roller Bearing for Aero-Engine by Finite Element Based Thermal Network Method

关键词:  航空发动机  主轴轴承  有限单元热网络法  节点划分  温度场

Key words:  Aero-engine  Main shaft bearing  Finite element based thermal network  Nodes-planning  Temperature distribution

摘要:

航空发动机主轴轴承温度场的精准预测对保证发动机润滑系统及整机稳定运转至关重要。针对传统热网络法精度低的问题，提出一种基于有限单元思想的有限单元热网络法。将轴承结构通过网格划分为有限个单元体，每个单元体设置一个温度节点代表该单元体的集总参数，节点间构建热阻关系并形成热网络，通过求解以温度为未知量的大型稀疏矩阵线性方程组来获得滚子轴承横截面的温度分布。该方法可以与轴承局部产热理论相结合，实现轴承局部产热的精准加载，完成温度场的精细化分析。通过与试验结果对比，本文方法对轴承外环表面中心线温度的预测结果与试验结果误差不超过13%。

Abstract:

An Accurate thermal prediction of main shaft roller bearings for aero-engine is key to ensure stable operation of engine lubrication system and the whole engine. Considering that traditional thermal network method is less accurate， a finite-element based thermal network method is proposed. The bearing is divided into a finite number of elements by mesh， and each element is provided with a temperature node representing lumped parameters of the element. Then thermal resistance relationship is established among adjacent nodes to form a thermal network. By solving the large sparse matrix linear equations， the temperature distribution in the cross section of roller bearing could be obtained. This method could be combined with the distributed bearing heat generation theory to achieve accurate local heat loading and precise temperature distribution analysis. By comparing with experimental results， it is found that the error of predicted centerline temperature of outer ring surface in the bearing is less than 13%.