汽油机活塞内冷油腔振荡冷却特性的仿真研究

为研究汽油机活塞内冷油腔在高转速下的振荡冷却效果,搭建了计算流体力学仿真模型,模拟研究了额定转速下内冷油腔的机油瞬态分布、壁面换热系数和换热速率,分析了机油喷射速度、喷孔直径、机油温度等喷射参数的影响,并采用Box-Behnken组合设计,以换热速率最大化为目标优化了喷射参数。结果表明,换热速率除了受喷射速度和机油温度的交互作用影响外,还与腔内充油率决定的机油振荡状况有关,并可与喷孔直径拟合成抛物线关系。

Simulation on Oscillating Cooling Characteristics in Gasoline Engine Pistons

A computational fluid dynamics simulation model was built to study the oscillating cooling characteristics in the gasoline engine piston at rated speed involving the transient oil distribution, the overall heat transfer coefficient and the heat transfer rate.The effects of oil jet parameters including the oil jet velocity, the jet diameter and the oil temperature on heat transfer were discussed. The Box-Behnken design was adopted to optimize the oil jet parameters with the aim to maximize the heat transfer rate. The results show that the heat transfer rate is affected by both the jet velocity and the oil temperature, is related to the oil oscillation condition determined by the oil fill ratio, and the fitting of the parabolic curve indicates a quadratic relation between the heat transfer rate and the jet diameter.