不同湍流模型柴油机喷嘴空穴流动的对比分析

摘要

建立了喷油嘴内部燃油两相流动CFD模型，基于界面追踪法( VOF)对比分析了应用LES湍流模型和标准k-ε湍流模型模拟空穴流动的结果。结果表明：大涡模拟方法得到的瞬态湍流运动呈现较明显的非对称分布，标准k-ε湍流模型模拟得到的湍流场比较均匀，而对称性比较明显。大涡模拟可以捕捉到更多的随机漩涡，对喷射的流场预报更为准确，更能反映流动的细节，有助于更加深刻地认识湍流的本质。%An internal nozzle two-phase CFD model was established based on the Volume of Fluids ( VOF) method to compare the cavitation simulation results of using LES turbulence model and the standard k-εturbulence model. The result shows that the transi-ent turbulent flow field is asymmetric computed by LES, while it is symmetrical computed by the standard k-ε turbulence model. On one hand, LES can describe the flow field more accuracy because it can capture more random vortexes. On the other hand, the LES can present the details of flow field, so it can help us to know the nature of turbulence deeply.