Investigation of the propagation modes for gaseous detonation at near-limit condition

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 C 2 H 2 +2.5O 2 +70%Ar and C 2 H 2 +2.5O 2 +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 C 3 H 8 +5O 2 , C 2 H 2 +5N 2 O and CH 4 +2O 2 (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. © 2018, Editorial Staff of EXPLOSION AND SHOCK WAVES. All right reserved.