Effects of ignition position on explosion of premixedpropane-airin a T-type pipe

Ignition position has an important influence on gas explosion, but few researches have been done on the ignition position in T-type pipe. In this paper, an experimental and numerical study of horizontal and vertical ignition positions in a T-type pipe has been presented. Results show that the ignition position has a great influence on the flame propagation velocity, flame structure and explosion pressure. In the case of vertical ignition, the maximum pressure appears near the T-type bifurcation, and there is an obvious stress concentration on the upper side wall of the bifurcation. In the case of horizontal ignition, the maximum pressure appears at the right end of the pipe, and a weak stress concentration occurring at the splitting point. When flame passing through the bifurcation, it takes 12 ms longer than ignition on horizontal, but the time for flame propagates from ignition to the end is less. The "tulip flame" forms three times after flame propagates the bifurcation when ignition on horizontal, but there is no "tulip flame" while ignition on vertical. In the case of vertical ignition, the scale of the vortex at the bifurcation is larger than that in the horizontal. The turbulent kinetic energy is mainly in the horizontal section when ignition on vertical, while it is mainly in the vertical pipe if ignition on horizontal.