氩气对乙炔预混气爆轰不稳定性的影响及量化分析

为定量研究氩气对预混气爆轰不稳定性的影响，在管径为50.8、63.5 mm的管道内对未稀释及氩气稀释(氩气的体积分数为50%、70%、85%)的C₂H₂-O₂预混气进行了实验研究和量化分析，通过烟膜轨迹获得了不同初始压力下各种预混气的爆轰结构。对烟膜图像进行数字化处理，得到了氩气稀释下C₂H₂-O₂预混气爆轰轨迹的不规则度表征:轨迹间距的柱状图、标准差曲线、自相关函数。结果表明:随着氩气体积分数的升高，三波点轨迹愈加规则，不稳定性在爆轰自持传播过程中逐渐失去主导作用。稀释后预混气爆轰轨迹间距的柱状图和自相关函数的峰值和分布离散情况基本一致，与标准差分布一致。C₂H₂-O₂-85%Ar、C₂H₂-O₂-70%Ar、C₂H₂-O₂预混气的柱状图主胞格尺寸占比分别为33%、23%、20%，标准差分别为2.66~6.60 mm、5.37~10.96 mm、27.63~36.67 mm，自相关函数的第1个最高峰值分别高于其他峰值1/3倍、1/6倍、1/7倍。通过分析标准差数据，拟合得到氩气的体积分数与不稳定度的多项式函数，为选取不稳定度和氩气稀释浓度提供了依据。

Effect of argon dilution on detonation instability of C2H2-O2 mixture and its quantitative analysis

To investigate quantitatively the effect of argon dilution on the detonation instability of C2 H2-O2 mixture,we carried out a digital comparison of smoked foils from C2 H2-O2 mixtures with different Argon dilutions (with an volume fraction of 50％,70％,and 85％,respectively) in two tubes (with an inner diameter of 50.8 mm and 63.5 mm,respectively) producing transverse waves of regular and irregular spacing and,based on the smoked foils,obtained under different initial pressures the histogram,the standard deviation and the autocorrelation function,which we then used to quantify the spacing irregularity for different cellular detonation structures.Each smoked foil was digitized and separated into left-running and right-running waves for subsequent analysis.The histogram,the standard deviation and the autocorrelation function showed consistent tendency.As the Ar dilution's volume fraction rose,the trajectory of the triple points became more regular.Similarly,mixtures of different Argon dilutions showed different degrees of irregularity in the analysis of the histograms and the autocorrelation function of the transverse waves' spacing.The proportion of the dominant mode of C2H2-O2-85％Ar,C2H2-O2-70％Ar,and C2H2-O2 were 33％,23％,and 20％,respectively,while their standard deviation was 2.66～6.60 mm,5.37～10.96 mm,and 27.63～36.67 mm,and their autocorrelation function peak values were higher by 1/3,1/6,and 1/7 times.A polynomial fitted curve of the dilution and the irregularity was drawn from the standard deviation data to provide a selection basis for the instability degree and the Ar dilution's volume fraction.