Propane–air pipe explosion experiments. Data for estimation of 1-D burning velocity in slow regimes

Abstract

Flame propagation in circular steel pipes with inner diameter of 22 mm and lengths of 1, 2 and 5 m has been studied experimentally. The combustible gas mixtures used were propane–air mixtures at various equivalence ratios, which sustain flame propagation in a slow regime in this pipe geometry. The results obtained are in agreement with comparable reported experiments. Initial flame propagation is governed by the laminar flame velocity, but the flame propagation in a slow regime will depend strongly on the acoustic oscillations in the pipe from the time when the first rarefaction wave, which was reflected at the pipe outlet, reaches the flame front. The main purpose of performing the experiments was to obtain a set of data for the numerical simulations. A quasi 1-D burning velocity is determined numerically with a Matlab version of the random choice method (RCMLAB) on the basis of the experimental pressure records. This estimated burning velocity is used as input to the combustion model in the RCMLAB code. It seems to be good agreement between the numerical results and experiments, except for some variance probably caused by the pipe outlet. The expansion at the pipe outlet is important for the acoustic oscillations and our results show the importance of the modelling of the outlet.