Flame propagation in a straight and 90-degree bend pipe for premixed hydrogen/air and methane/air

Abstract

This paper reports on the experimental and numerical analyses towards understanding the flame propagation in hydrogen and methane explosions, with the effect of pipe configurations. The experimental works were performed in a straight and 90-degree bend pipe with the length to diameter ratio, L/D is 51. FLACs code simulation was adopted to investigate the dynamic of flame behaviour in both pipe configurations. From the results, it was observed that the presence of 90-degree bend enhances the explosion severity by a factor of 1.03-3.58 as compared to that of the straight pipe. Based on the simulation analysis, the compression effect at the bending region and at the end of the pipe plays an important role to attenuate the burning rate, which results to the increase of the pressure wave. Furthermore, compression effect is the main mechanism for the flame to propagate and potentially lead to a catastrophic explosion.