发动机排气管热结构有限元分析

Finite Element Analysis of Thermal Structure of Engine Exhaust Manifold

针对发动机排气管在使用中出现开裂的问题,对开裂部位进行热结构分析,利用UG构建发动机排气管三维CAD模型,采用流体计算软件Fluent和有限元软件ANSYS对排气管进行热流固耦合仿真分析,得到排气管温度场和热应力分布情况,并与排气管热冲击循环试验的结果相比较,流固耦合仿真的结果与试验结果基本一致,验证了所构建的排气管流固耦合热结构模型是正确的,同时也证明了排气管出现裂纹是由于其热应力太高造成的。

The paper, in the light of the crack problems on the engine exhaust manifold, analyzes the thermal structure of the cracking position, creates the 3D CAD model of the exhaust manifold based on UG, investigates numerically the thermal structure by using the Fluent and ANSYS software so as to obtain the distribution of the temperature in the solid, the stress state and the deformation of the exhaust manifold and compares the simulation analysis results with the thermal shock cycling experimental results of the exhaust manifold and concludes that the calculation results well agree with the test data, thus it is verified that the thermo-fluid-solid coupled model is correct and the cracks on the exhaust manifold are caused by high thermal stress.