某发动机排气歧管优化设计

为了分析某发动机排气歧管的设计是否合理，文章对该排气歧管的内流场进行了CFD分析。通过CFD计算，得到催化器裁体前端的速度均匀性系数、氧传感器周围的最大流速和最大流速差异性系数。根据评价标准，当前设计状态不能满足要求。最后对排气歧管的汇总管进行了优化设计，并对优化设计再次进行了CFD分析，结果表明优化后的模型满足性能要求。

The Optimization Design of Exhaust Manifold on a Certain Engine

In order to analyze whether the design of exhaust manitbld on a eerlain engine was rational or not. CFD analysis ,m tile internal flmv field of lhe exhaust manifold is eondueted. Througb CFD calculation, veloeity uniform index in the front of subsh＇ate of ealalyst, average tlow veloeity （AFV） and flow speed difference （FSD） around oxygen sensor are obtained. According to evaluation standard, the eurrenl design status can not meet the performance requirements. A1 last optimizalion design of total pipe of exhaust manifold was earried out as well as CFD analysis. The result showed that the optimization model can meet the performance requirenmnts.