中文摘要：

通过修改发动机多维CFD计算程序KIVA-3V，建立了内燃机压缩过程冷态流场的大涡模拟（LES）计算模型．利用此模型对内燃机压缩过程中缸内流场的水平速度及湍流动能进行分析，同时，分析了网格密度对内燃机缸内流场大涡模拟的影响．结果表明，当采用κ-ε模型计算时，网格的精细程度对流场结构影响不大；在相同的计算网格下，与采用κ-ε模型计算相比，采用LES计算显示了更为复杂的湍流结构，而且LES所能捕捉到的涡团结构范围要大于κ-ε模型，计算得到的湍流动能也要低于κ-ε模型；同时，网格越精细，这种效应越明显．

英文摘要：

By amending the engine CFD package （KIVA-3V）, a large-eddy simulation （LES） model of turbulent flow in the compression process of an internal combustion engine was built. The horizontal speed and turbulent kinetic energy of the turbulent flow in the compression process were simulated by this model. Furthermore, the effects of mesh density on large-eddy simulation of turbulent flow in the cylinder were analyzed. The results show that mesh density has litter effect on the fluid structure when the κ-ε model is adopted. Compared with the κ-ε model, the LES model shows a significantly different and relatively more complex turbulent structure. Furthermore, the LES model can capture a wider range of vortical structures than the κ-ε model, and its turbulent kinetic energy is much lower than that of the latter. At the same time, the finer the mesh is, the more distinct the effect is.