Investigation of the propagation modes for gaseous detonation at near-limit condition
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摘要: 选用五种碳氢混合气体,采用高压电火花起爆的方法,利用光纤探针测量爆轰波在管道内的传播速度,研究临近失效状态时爆轰波在管道内的传播模式。实验是在自行研制的爆轰管道中进行的,其包括驱动段及内径分别为1.5、3.2、12.7 mm三种规格的测试段。实验结果再次验证了爆轰波在管道内传播时可以有六种不同的传播模式:稳态爆轰、快速波动爆轰、结巴式爆轰、驰振爆轰、低速爆轰和爆轰失效。其中C2H2+2.5O2+70% Ar、C2H2+2.5O2+85% Ar两种组分混合气体(具有较低活化能),在爆轰波传播过程中只有稳态、快速波动和失效三种模式;而C3H8+5O2、C2H2+5N2O和CH4+2O2三种组分混合气体(具有较高活化能)在传播过程中出现六种不同模式。上述结果表明,除气体组分、初始压力等因素外,混合气体的活化能可能对爆轰波在管道内的传播状态也有影响。Abstract: In this paper, five kinds of hydrocarbon gaseous mixture were selected as working medium. By using high voltage spark ignition method and optical fiber probe, the propagation velocity of detonation wave in pipeline was measured near failure state condition. Experiments were conducted based on a self-made detonation pipeline, which includes a drive section and three different test sections with 1.5-mm, 3.2-mm and 12.7-mm inner diameter, respectively. Experimental results reverified that there are six different propagation modes, which are steady detonation, rapid fluctuation detonation, stuttering detonation, galloping detonation, low velocity detonation and detonation failure, respectively for pipeline detonation. Among them, gaseous mixtures C2H2+2.5O2+70%Ar and C2H2+2.5O2+85%Ar (both have low activation energy), have only three propagating modes, i.e. steady, rapid fluctuation and failure modes; while for other three gaseous mixtures C3H8+5O2, C2H2+5N2O and CH4+2O2 (with higher activation energy), there are six different propagating modes. The results show that besides gas composition and initial pressure, the activation energy of gaseous mixture may also affect the propagation state of detonation wave in pipeline.
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Key words:
- detonation wave /
- propagation mode /
- velocity fluctuation /
- activation energy
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表 1 不同管径和初始压力下五种碳氢混合物爆轰传播模式分类
Table 1. The various evlution modes of the five tested mixtures in different diameter tubes and initial pressures
p0/kPa C2H2+2.5O2+70%Ar C2H2+2.5O2+85%Ar C2H2+5N2O C3H8+5O2 CH4+2O2 1.5 3.2 12.7 1.5 3.2 12.7 1.5 3.2 12.7 1.5 3.2 12.7 1.5 3.2 12.7 98 2, 4 84 1 2 80 1 1 4 60 1 1 1 1 1 1 4 2 57 6 55 1 1 6 1 1 1 2 50 1 1 1 1 1 4, 5 2 40 1 1 1 1 1 1 1 4, 5 4 1 36 1 1 1 1 1 1 4, 5 1 34 1 1 1 2 4, 5 1 32 1 1 1 2 1 4, 5 4 1 30 2 1 1 1 1 2 1 1 2 1 1 6 4 1 29 1 2 2, 4 28 2 2 1 6 1 2 1 1 2, 4 1 1 6 4 1 26 2 2 1 2, 4 1 1 2, 4 1 1 5 1 24 2 1 2, 4 1 1 4 1 1 5 1 22 2 2 1 1 4 1 1 4 1 1 5 1 20 2 2 1 1 4 1 1 1 1 5 2 18 6 2 1 1 4 1 1 1 5 2 16 2 1 1 4 2 1 4 2 1 5 2 15 1 2 6 2 3 14 2 1 1 4 2 1 1 5 3 12 2 1 1 4 2 1 4 1 3 10 2 1 5 4 1 4 1 5 4 8 6 1 5 4 2 4 1 6 4 6 6 2 6 4 2 4 2 6 4 4.5 2 3 4 2 5 2 5 3, 4 4 3 6 4 6 4 6 2 6 4 6 4 6 1 6 6 注:表中管径的单位为mm。 -
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