关键词: 油气爆炸, 障碍物数量, 爆炸超压, 火焰速度, 湍流, 混合物, 实验验证

Abstract:

In order to investigate the effects of obstacle number on the characteristics of vented gasoline-air mixture explosions, a series of contrast experiments were conducted under three different initial gasoline vapor concentrations in terms of the obstacle number, the conclusions show that: (1) There existed three typical pressure peaks denoted as p_v, p_max, and p_neg during the gasoline-air mixture explosions in a semi-opened pipe, and the magnitude of p_v was just associated with the fracture constant of the polyethylene film at the pipe exit but not with the obstacle number, while the magnitudes of p_max and the absolute values of p_neg increased with the growth of obstacle number, and the time to obtain the p_max was not fully dependent on the obstacle number. (2) During the initial flame propagation process, the flame remained a “finger-like” shape, while disturbed by the obstacles, the flame fronts became distorted, and they were accelerated to change from laminar flame to turbulent flame. And finally the flame fronts formed a “mushroom-like” shape outside the pipe, and the more obstacles, the more significant the “mushroom-like” shape. (3) The obstacles had significant effects on the flame acceleration, and the maximum flame speeds increased with the growth of the obstacle number. (4) Overpressure and flame propagation of the explosion process of gasoline-air mixture explosions had a positive feedback coupling relationship between incentives, they promoted with each other during the evolution of explosions, and the coupling relation became more significant with the growth of obstacle number. (5) The effects of obstacle number on the enhancement of p_max and maximum flame speeds for initial gasoline vapor concentrations of 1.3% and 2.1% were more obvious than that of 1.7%.

Key words: gasoline-air explosions, obstacle number, explosion overpressures, flame speeds, turbulent flow, mixtures, experimental validation