龚金科 卜艳平 钟超 胡辽平 陈少林

摘 要：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.

关键词：涡轮箱；隔热罩；轴承体；耦合传热；热应力

中图分类号：TK411.8 文献标志码：A

Abstract：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.

Key words：turbine box； heat shield； bearing； coupled heat transfer；thermal stress

增压器在高温、高速的环境下工作，使得涡轮箱、涡轮叶片、轴承体、浮动轴承等关键零部件承受非常高的温度及热应力.日益严格的经济性、环保性要求使得增压器的强化程度不断提高，其热负荷、冷却散热问题严重影响了增压器结构强度和可靠性.且轴承和密封环受轴承体热负荷的影响，其使用寿命明显降低，成为增压器可靠性中的一个薄弱环节[1-3].

增压器冷却散热系统如果不能有效降低轴承体的温度，在长时间工作中就会使轴承体零部件产生热疲劳，同时还会进一步降低机油润滑效果和承载能力.长期以来对轴承体进行流固耦合传热分析时，采用的是轴承体涡轮端……