射流冲击冷却过程的数值研究

由于冲击射流流场较为复杂,为准确描述其流动和换热过程,需要选择合适的湍流模型和壁面函数.分别采用κ-ε模型(Standard,RNG和Realizable)、κ-ω模型(Standard和SST)和低雷诺数模型(AB,AKN,CHC,YS,LB,LS和YS)进行对比计算.对于壁面区域,考察了标准壁面函数、尺度化壁面函数、非平衡壁面函数和增强型壁面函数的影响.探讨了速度场和湍动能场的分布规律,获得了与实验一致的结果,为今后活塞底部喷油冷却的数值模拟提供基础.

Numerical Study of Jet Impingement Cooling Process

In the process of engine working， bottom injecting cooling can effectively reduce the piston temperature. Due to the complex flow field of jet impinging， an appropriate turbulence model and wall function must be utilized to describe the flow and heat transfer process. The κ-ε model (Standard， RNG and Realizable)， κ-ω model (Standard and SST) and low Reynolds number model (AB， AKN， CHC， YS， LB， LS and YS) were calculated and compared. The effects of the standard， scalable， non equilibrium and enhanced wall functions were analyzed for the wall region. Distribution law of the velocity and turbulent kinetic energy field were discussed， which are in accordance with the experiments. These results provide a basis for future numerical simulation of ejecting oil cooling at piston bottom.