适用于内燃机的非线性三方程模型的一个新方案

A New Version of the k-ε-A_2 Nonlinear Three Equation Model for Internal Combustion Engines

提出了非线性三方程 k-ε- A2 湍流模型的一个新方案。此模型采用雷诺应力张量和应变张量的三阶相关关系 ,该关系式中出现的雷诺应力第二不变量 A2 是通过求解其输运方程得到的。用此模型对几种内燃机缸内的流场进行计算 ,结果表明此模型克服了各种涡粘度模型不能反映平顶活塞压缩上止点处各向异性的特点 ,此模型在定量和定性上较之 k-ε模型有较大的改进。

A new version of the k ε A 2 nonlinear three equation model is presented.This model adopts a cubic relation between the stress and strain/vorticity tensors and solves an additional (third) transport equation for the second invariant of the stress anisotropy tensor.As all models in the category of EVM are not able to predict anisotropy at TDC of compression stroke of the internal combustion engine with flat face pistons,so this paper introduces an additional term to the constitution equation in the nonlinear three equation model.Numerical results show that the modified nonlinear three equation model overcomes the default and it may give better prediction than the k ε model.