Experimental study on explosion overpressure and flame propagation characteristics of simulated vertical dome oil tank

Abstract

In order to study the development law of gasoline-air mixture explosion in vertical dome oil tank, a series of experiments are carried out in simulated oil tank. It is found that the development of overpressure in internal field can be divided into three stages: the overpressure rising stage, the overpressure relief stage and the overpressure oscillation and attenuation stage. The maximum overpressure peak, average overpressure rise rate and maximum overpressure rise rate in internal field all increase first and then decrease with the increase of gasoline vapor volume fraction. However, the formation time of the maximum overpressure peak, the maximum negative overpressure and the average pressure relief rate have opposite numerical trends. All of these peaked at the initial gasoline vapor volume fraction of 1.7%. The external field pressure wave of gasoline-air mixture explosion has a great relationship with spatial azimuth. With the increase of proportional distance, the pressure wave of external field at any angle shows the exponential decay law in form of Pext=kR−α. The relationship among the maximum overpressure peak, distance and direction can be uniformly expressed by a formula. With the increase of gasoline vapor volume fraction, the maximum overpressure peak at the nearest measurement point in the direction of dome opening increases first and then decreases, and the formation time of the maximum overpressure peak changes in the opposite trend, which can be expressed by cubic polynomials. The flame propagation of gasoline-air mixture explosion can be divided into three stages: the in-tank development stage, the vent explosion stage and the free burning stage. In addition, affected by fluid instability during explosion propagation, the positive feedback mechanism makes the development of explosion more and more intense.