甲醇与汽油进气道喷雾撞壁特性对比

Comparison of Intake Port Spray Impingement Characteristics of Methanol and Gasoline

为了探究甲醇发动机冷启动困难的本质,基于外轮廓修正策略构建了透明气道模型,并采用光学畸变矫正技术,可视化对比研究了进气温度、进气流量和喷射压力对进气道甲醇和汽油喷雾特性的影响.结果表明:进气温度的升高增加了甲醇和汽油喷雾面积,并且对汽油促进效果更好,在一定程度上减少了喷雾湿壁长度.进气流动促进了甲醇和汽油喷雾的发展,并使甲醇喷雾面积大于汽油,但高进气流量下喷雾湿壁严重,合适的进气流量为15~30 m^(3)/h.提高喷射压力,增加了喷雾贯穿距和喷雾面积,但是喷雾湿壁长度也随之增加,合适的进气道相对喷射压力为0.2 MPa.

To explore the essence of the cold start difficulty of methanol engine,a transparent intake port was constructed based on the outer contour modification strategy.The effects of inlet temperature,inlet flow rate and injection pressure on intake port spray characteristics of methanol and gasoline were visually studied by using optical distortion correction technology.The results show that the increase of inlet temperature improves the spray area and reduces the spray wet wall length to a certain extent,in which gasoline presents a better effect than methanol.The inlet flow promotes the development of methanol and gasoline spray and makes the spray area of methanol larger than that of gasoline.However,the spray wet wall is serious at high inlet flow rate.Increasing the injection pressure increases spray penetration and spray area,but the spray wet wall length is also increased.It is also found that a better spray characteristic can be obtained at the inlet flow rate of 15-30 m^(3)/h and the intake port relative injection pressure of 0.2MPa.