Abstract: 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.

Key words: oscillating-oil-cooling channel, jet impingement, multiphase flow, turbulence model, wall function