柴油喷雾特性试验研究

Experiment Study on Diesel Spray Characteristics

基于高速摄影直拍和纹影法对较高背景温度和背景压力状态下的柴油喷雾特性进行了研究.通过MATLAB的图像处理功能对试验图片进行处理.其中,高速摄影直拍图片采用阈值将油束与背景分离,得到喷雾液相发展过程;纹影图片采用相邻两图做差并累加得到含有气相的总的雾注发展过程,并将液相油束轮廓导入,得到最终的处理结果图.最后,根据得到的气液相边界点坐标,计算出喷雾宏观特性.采用该试验以及图片处理方法,研究了喷油压力对喷雾特性的影响,为燃烧系统匹配与数值计算模型标定提供更为全面的数据支持.

By means of a high - speed photography and the schlieren method, its diesel spray characteristics of an engine were studied under the conditions of higher temperature and larger pressure. The image processing functions in MATLAB were used to deal with the testing images. For the images from the high -speed photography, the threshold was used to separate the oil beam with its background for getting the development process of the liquid spray. For the schlieren images, the subtractions of the adjacent figure were accumulated for obtaining the development process of the total spray with gaseous phase and then the liquid spray profile was added for acquiring a final figure processing result. Finanly the macroscopic characteristics of the spray was calculated according to the coordinates from the gas - liquid boundary point. By using the experiment and the above mentioned method, the influence of the injection pressure on the spray characteristics was studied, providing a comprehensive data support for the matching of a combustion system and the calibration of its numerical model.