模拟立式拱顶油罐内油气爆炸实验研究

为探究立式拱顶油罐内油气体积分数、点火位置和液位对爆炸超压特性参数与火焰发展的影响规律，开展了一系列的实验研究，得到以下结果:（1）1.7%是任一工况下的最危险油气体积分数，内场超压发展都可以分为超压上升、超压泄放和振荡衰减3个阶段。爆炸过程中CH、C₂、OH等自由基的生成和空间分布，使得不同初始油气体积分数下或不同爆炸阶段的火焰呈现不同的颜色变化。（2）点火位置对油气爆炸超压特性参数的影响较大，位置越靠下，爆炸威力越大。罐底中心点火时，内外场平均升压速率取得最大值，分别为0.46和0.05 MPa/s。（3）液位变化对油气爆炸内外场超压的影响较大，油罐侧壁上部位置点火时，50%液位是最危险的液位。任意液位下外场超压随比例距离的增大都呈现幂指数衰减规律，不同液位下油气爆炸外场冲击波超压峰值与距离和油气混合物体积的关系可以用一个公式统一表示。相比于气相空间，液相空间的超压变化具有延后性、负压增强和振荡衰减更快的特点。

Experimental study of gasoline-air mixture explosion in imitated vertical dome oil tank

To investigate the influence of gasoline-air mixture volume fraction, ignition position and liquid level on explosion overpressure parameters and flame development in vertical dome oil tank, a series of experiments with nine initial hydrocarbon volume fractions, four ignition positions and five liquid levels were carried out in a transparent imitated oil tank. Dynamic data acquisition system and high-speed camera were employed to detect the changes of internal and external field pressure, and to record the transformation of flame shape. The following results were found. (1) 1.7% is the most dangerous gasoline-air mixture volume fraction under any working condition. The development of overpressure in the inner field can be divided into three stages: overpressure rise, overpressure release and oscillation attenuation. The formation and spatial distribution of free radicals such as CH, C₂ and OH during the explosion process make the flame show different color changes under different initial volume fractions or at different explosion stages. (2) Ignition position has a great influence on explosion overpressure parameters. The lower the ignition position is, the greater the explosion power is. When the ignition position is in the center of the bottom of the tank, the average pressure boost rate of the internal and external fields reaches the maximum value, being 0.464 MPa/s and 0.053 MPa/s, respectively. (3) The change of liquid level has a great influence on the overpressure of the internal and external field of oil and gas explosion. When the position ignition is located at the top of the side wall of the oil tank, the 50% liquid level is the most dangerous level. At any liquid level, the outfield overpressure decreases exponentially with the increase of scaled distance. The relationship among the maximum overpressure peak of the outfield shock wave of gasoline-air mixture explosion at different liquid levels, the distance and the volume of gasoline-air mixture can be expressed by a unified expression. Compared with gas space, the overpressure in liquid space has the characteristics of delay, enhancement of negative overpressure and faster oscillation attenuation frequency.