关键词: 油气泄压爆炸, 障碍物位置, 爆炸超压, 火焰速度

Abstract:

To investigate the effect of obstacle position and oil-gas concentration on characteristics of gasoline-air mixture explosion, a series of contrast experiments were conducted under the condition of three different initial gasoline vapor concentrations (1.3%, 1.7% and 2.1%) and different obstacle positions. The main observed results are:(1) Three typical peak values are observed in gasoline-air mixture explosion. The peak value of pressure relief p_v is independent of obstacle position, while the maximum absolute value of negative pressure peak p_neg is obtained when the dimensionless distance between the obstacle and the igniter head L_i/L=0.4. In the condition of 2.1% concentration, the peak value of maximum overpressure p_max is obtained at L_i/L=0.4, while under the condition of 1.3% concentration, it is obtained at L_i/L=0.6. (2) The maximum values of average pressure boost rate (dp/dt)_ave, index of explosive power E_max, maximum pressure boost rate (dp/dt)_max and maximum explosion index K_max are all obtained at L_i/L=0.4 under the condition of three initial concentrations. (3) During the initial flame propagation process, it presents a “finger-like” shape, while after disturbance by obstacles, the flame fronts produce irregular deformations, a mushroom like flame is formed outside the pipe. When L_i/L=0.2, mushroom like flames are most pronounced. (4) The maximum flame propagation velocity S_fmax is obtained at L_i/L=0.2 which monotonously decreases with the increase of L_i/L from 0.2 to 0.8. Above observation results show that both location of obstacles and initial oil gas concentration have an influence on the characteristic parameters of the gas explosion in the pipeline with built-in obstacles.

Key words: vented gasoline-air mixture explosions, obstacle position, explosion overpressures, flame speeds