用非线性三方程模型计算内燃机缸内湍流流动

Application of the Nonlinear Three Equation Model to in-Cylinder Turbulent Flows in ICE

内燃机整个工作循环中 ,其缸内流体始终进行着极其复杂而又强烈瞬变的湍流运动 ,正确地模拟和分析内燃机的燃烧和排放 ,离不开对缸内湍流运动的正确描述和模拟。把一个非线性三方程k -ε -A2 .湍流模型修正后应用于内燃机缸内湍流计算 ,此模型采用了雷诺应力张量和应变张量的三阶相关关系 ,表示雷诺应力张量和应变张量相关关系方程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 ,计算采用任意拉格朗日欧拉法。用此模型对几种内燃机内的缸内流场进行计算 ,给出了用非线性三方程模型计算得到的结果 ,并与标准的k -ε模型算得的结果和实验结果进行了比较 ,结果表明 。

Fluid flows in internal combustion engine cylinders are more complicated, forceful transient and turbulent flows at entire circle. For this reason, correct simulation and analysis of combustion and discharge of internal combustion engines need correct description and simulation of in-cylinder turbulent flows. After being modified, a k-ε-A 2 nonlinear three-equation model was appllied to in-cylinder turbulent flows in ICE. This model adopts a cubic relationship between the stress and strain/vorticity tensors but broadens the range of flows to which the model applied by including a third transport equation for second ivariant of stress anisotropy. The computations are based on the arbitrary Lagrangian-Eulerrian method. Numerical results are given and compared with experimental results for in-cylinder flows at several engines. The result shows that the new model may give better prediction than the k-ε model and it is suitable for the internal combustion engine flows.