基于Python的CO_(2)/O_(2)氛围下柴油燃烧火焰特征分析

Python-based flame characterization of diesel combustion in CO_(2)/O_(2) atmosphere

为分析柴油在CO_(2)/O_(2)氛围下燃烧的火焰特征,利用光学定容燃烧室测试并拍摄了6种不同工况下的柴油燃烧过程.基于自编的Python代码对火焰图像进行后处理,提取出火焰浮起长度、红绿分量比、平均亮度、相关性系数、面积变化率和重叠率等特征参数并进行分析.结果表明:在空气和CO_(2)/O_(2)氛围下,柴油火焰浮起长度和相关性均随燃烧进程先增大后减小再增大,平均亮度则先增大后减小,其在空气下和35%CO_(2)+65%O_(2)氛围下的峰值分别为210.75 px和138.89 px.在火焰发展阶段,红绿分量比保持在0.8~1.2之间,而在火焰熄灭阶段,随着CO_(2)浓度减小和O_(2)浓度增大,红绿分量比有所减小.与在空气下燃烧相比,柴油在CO_(2)/O_(2)氛围下的燃烧火焰形状更加细长,湍流现象更加明显,火焰浮起长度缩短,平均亮度下降.

To analyze the combustion characteristics of diesel fuel in a CO_(2)/O_(2)atmosphere,optical constant volume combustion chamber tests were conducted to measure and capture the combustion processes under six different operating conditions.The resultant flame images were subject to post-processing using custom Python code,enabling the extraction of parameters including flame lift-off height,red-green ratio,average luminosity,correlation coefficient,area change rate,and overlap ratio.The findings indicate that,in both air and CO_(2)/O_(2) atmospheres,the flame lift-off height and correlation initially increase,then decrease,before experiencing a subsequent increase throughout the combustion process.Conversely,the average luminosity demonstrates an initial increase followed by a decline.Specifically,in the air and 35%CO_(2)+65%O_(2) atmospheres,the peak values of flame lift-off height were measured as 210.75 px and 138.89 px,respectively.During the flame development stage,the red-green ratio remains within the range of 0.8 to 1.2,while in the flame extinction stage,it decreases as the CO_(2) concentration decreases and the O_(2) concentration increases.Compared to combustion in air,the combustion of diesel fuel in a CO_(2)/O_(2) atmosphere displays an elongated flame shape,heightened turbulence,reduced flame lift-off height,and diminished average luminosity.