汽油喷雾碰壁和油膜形成的可视化试验与数值模拟

Visualization Research of the Gasoline Spray-wall Interaction and Wall Film Formation and Numerical Simulation

进气道喷射汽油机混合气形成对燃烧和排放起着重要的作用。为了研究汽油喷雾碰壁过程,利用定容燃烧弹进行了汽油喷雾碰壁直接高速摄影,研究了不同倾斜角度壁面、不同壁面粗糙度和碰壁距离等对喷雾碰壁和油膜形成的影响。在此基础上,利用CFD软件建立了定容燃烧弹内汽油喷雾碰壁和油膜形成过程的三维数值模型。测量了定容燃烧弹内的压力,并与理论值进行了对比分析。研究结果为汽油机进气道喷射系统的设计提供了参考。

The mixture formation in port fuel injection （PFI） engine plays an important role in combustion and emission. To study the spray-wall interaction process, the impingement of spray against metallic wall was visualized using high speed CCD in a constant volume bomb. The effects of different impingement angles, wall roughness and injection distances on wall film, splash, evaporation as well as mixture formation was investigated and the mean pressure of the constant volume combustion bomb was measured. Meanwhile, 3D numerical model was utilized to simulate the impingement process. The simulated results show good agreement with the measurement. The experimental and simulated results provide useful guide for gasoline PFI system.