Thermal Load Research Of Exhaust Manifold

The exhaust manifold is installed in the engine cylinder outlet,the exhaust manifold outlet is communicated with the exhaust main,and the exhaust manifold is the primary part of all exhaust devices.During the operation of the vehicle,the engine is constantly stopped or started,and the exhaust gas emitted by the engine is easy to produce thermal fatigue damage to the exhaust manifold.The exhaust manifold bearing high temperature ability has great influence on engine exhaust emissions,exhaust manifold under high temperature load from the engine cylinder alternating,due to the complex structure of the exhaust manifold,will cause the local temperature is too high.This will result in a large local deformation of the exhaust manifold,which may lead to cracks,leaks,or cracking.So as one of the important parts of the engine exhaust system,exhaust manifold structure itself and thermodynamic properties have a great influence on the exhaust,it is necessary to study the thermal load of the structure in order to ensure that the engine can work normally and the exhaust gas can be discharged smoothly.Based on the defects of the exhaust manifold,this paper takes the exhaust manifold of the four-in-one structure of 1.6L engine to simulate the high temperature load.Firstly,the internal flow field grid model and the exhaust manifold structure grid model are established by using the software ANSY Meshing.Then use the Fluent fluid mechanics analysis software to analyze the flow state of the exhaust manifold internal high temperature gas,the distribution of pressure,velocity and pathlines in the fluid domain is studied by the given boundary conditions.The analysis of heat transfer of the exhaust manifold and its internal fluid structure coupled with ANYSY Workbench Steady-State Thermal,according to the analysis of the inner surface of the heat transfer coefficient and the fluid temperature to research the temperature distribution,thermal stress distribution and thermal deformation of the exhaust pipe under different installation constraints,predicting the thermal fatigue life of plastic and analyzing thermal load of exhaust manifold.Based on the above research,the optimization design of exhaust manifold structure is presented to improve the service life.