Explosion-induced ignition and combustion of acetylene clouds

Abstract

We investigate the explosion-induced ignition and combustion of an acetylene cloud in a rectangular chamber ( $$10\,\hbox {cm}\times 10\,\hbox {cm} \times 39\,\hbox {cm}$$ ). In the experiments, a 0.2-g PETN charge was located at $$x = 9.7\,\hbox {cm}$$ and a soap bubble ( $$d = 5\,\hbox {cm}$$ ) filled with pure acetylene was located at $$x= 27\,\hbox {cm}$$ as measured relative to the end wall. Detonation of the charge created a blast wave that crushed the soap bubble—inducing mixing with the air. After 0.55 ms, the mixture ignited, forming at turbulent combustion cloud. The flow was modeled using the compressible Navier–Stokes equations assuming unity Lewis number. Arrhenius-based kinetics were used to model ignition. Adaptive mesh refinement was used to capture turbulent mixing on the grid (the MILES approach of J. Boris). Computed pressures were found to be in agreement with measured pressure histories. Finite-rate kinetics were required to capture the ignition processes over the duration of the experiment.