空心喷雾油滴碰撞热多孔介质的数值研究

为加深对多孔介质发动机中均匀混合气形成的了解,用改进的KIVA-3V详细模拟了空心喷雾油滴碰撞热多孔介质的过程。在KIVA-3V中增加了油滴碰撞热多孔介质壁面的碰撞模型、传热模型及空心喷雾的线性不稳定性液膜破碎(LISA)模型。油滴与热壁的碰撞模型和传热模型经检验证明了其合理性。在简化多孔介质结构的基础上,在不同的环境压力及喷雾锥角下,模拟了空心喷雾与热多孔介质的相互作用。计算结果表明:油雾在碰撞到热多孔介质后,发生分裂的油束和多孔介质区域的高温,促使油滴实现快速蒸发并为油蒸汽与空气充分混合创造了前提。不同的空间压力及喷雾锥角直接影响到油滴在多孔介质中的分布。

Numerical Investigation of Hollow Cone Spray Impinging on a Hot Porous Medium

In order to study the mixture formation in porous medium engine,a numerical simulation for the interaction of hollow cone spray and a hot porous medium was conducted.The improved KIVA-3V code,which incorporates impingement model,heat transfer model and linearized instability sheet atomization(LISA) model,was used to simulate the process of fuel droplets impinging on a hot porous medium.The reasonability of the impingement model and heat transfer model was validated.With the structure of the hot porous medium being simplified,the interaction of hollow cone spray and the porous medium were simulated in detail.Computational results for the interaction of fuel spray and the hot porous medium show that after fuel spray impinges on the hot porous medium,the broken-up fuel spray and the high temperature of the porous medium can provide conditions for fast evaporation of fuel droplets and mixing of fuel vapor with air.Changing ambient pressure and spray cone angle can directly affect the distribution of droplets in the porous medium.