增压器总体传热研究下的轴承体热应力分析

基于耦合传热理论,建立了废气旁通阀式的涡轮箱模型,并将涡轮箱、隔热罩、轴承体作为一个装配体进行了传热分析,得到了轴承体的温度场和热应力分布.结果表明:温度从涡轮箱至轴承体逐渐降低,呈现明显的温度梯度,涡轮箱的最高温度比初始废气温度低71.5 ℃左右;由于隔热罩的隔热作用和冷却水、机油的双重冷却作用,轴承体的温度较低;由于轴承体内部和表面区域温差较大,其热应力较高.与实验对比,轴承体温度的仿真值与实验值误差最大为7.2%,说明该仿真方法具有较高的精度,能为增压器的设计和优化提供一定的理论依据.
Based on coupled heat transfer theory, a model of turbine box with waste gate was built, and turbine box, heat shield and bearing body was tied as an assembly to be heat transfer analyzed. Temperature and thermal stress analysis of bearing body were then obtained. The results show that temperature is gradually reduced from turbine box to bearing body, which presents an obvious temperature gradient. And the temperature of turbine box is about 71.5℃ lower than original gas temperature. Because of good insulation of heat shield and dual cooling of cooled water and oil, the temperature of bearing body is low. However, the thermal stress of bearing body is high due to its temperature difference between inside and outside surface. Compared with the test results, the maximum deviation between the simulated and experimental value is 7.2%, which verifies that this simulation method has high precision and can provide a theoretical basis for the design and optimization of turbocharger.