二气门汽油机缸内冷态流场的大涡模拟

LARGE-EDDY SIMULATION OF COLD FLUID FIELD OF TWO-VALVE GASOLINE ENGINE

通过修改发动机多维CFD计算程序KIVA-3V,建立了内燃机缸内冷态流场的大涡模拟(LES)计算模型。利用此模型对二气门汽油机进气与压缩过程中缸内流场进行了详细分析,并与κ-ε、RNGκ-ε模型进行了比较。结果表明与采用κ-ε、RNGκ-ε模型计算时相比,采用LES计算时显示了更为复杂的湍流结构。同时,采用LES计算时除能得到有序的大尺度涡团结构外,还能捕捉到大量不规则的小涡团结构,而采用κ-ε、RNGκ-ε模型进行计算时,基本上捕捉不到不规则的小涡团结构。

By amending the engine CFD package（KIVA-3V）,the large-eddy simulation（LES） model of turbulent flow in the internal combustion engine was built.The turbulent flow fields in the intake and compression strokes of a two-valve gasoline engine were simulated by this model and the computational results were compared with that ofκ-εand RNGκ-εmodel.The results show that comparing withκ-εand RNGκ-εmodels,LES model shows a relatively more complex turbulent structures.Furthermore,comparing withκ-εand RNGκ-εmodels that only can capture the coherent large-scale vortical structures,computation using LES can capture both the coherent large-scale vortical structures and the irregular small-scale vortical structures.