Experimental Research Of The Overpressure Field Of Flammable Vapor Explosion

The process of unconfined gas cloud explosions belongs to complicated explosive process. When the explosive flame meets all kinds of obstruction in the spreading process, the explosion overpressure will increase variably, thus will increase the explosive power of the explosion. The research of the rules of the unconfined gas cloud explosions of built-in obstructions has important social significance and economic values.In this paper,with the C2H2 - Air as the media, the experimental research on effects of premixed flammable gas cloud explosions induced by semi-spherical-baggy obstiaictions was conducted. The main work and conclusions are as follows:1) An experimental system consisting of pressure transducers, data acquisition card, computer and electric spark ignition device was set up to study the pressure field on the semi-spherical obstructions with strip space in case of flammable gas cloud deflagration.2) A series of perpendicular experiments were conducted on C2H2-Air flame acceleration resulted from hemispherical bar grating barriers in hemispherical gas cloud. The results show that the radius r,angle a play a distinctive role on explosion overpressure.But their interactions do not have any remarkable effects on explosion overpressure.3) Aimed at the effects on overpressure of each characteristic factor of the obstructions,an experiment was conducted, in this way, the working rules of each effective factor on the explosion overpressure was certained.The overpressure △p increases with the rising of the radius of the flammable gas R, the size of the obstruction and the angle a ,and decreases with the increasing of interspaced ratio of barrier φ and distance between the dots d.4) Based on the regression of experimental data and deviation analysis, the fitting equation is obtained between the explosive overpressure △p and its influential factors: obstacle characteristic parameters(r, φ), gas cloud radius R, distance between the dots d .The connection between the overpressure and effective factors concluded from the fitting equation coincides with the experimental conclusion concerning the effects of eachcharacteristic factor on the overpressure.With the analysis and examination,the connection between the fitting equation and the experimental data was verified.5) Leading to the Multi-energy method thought in the present experiments, if the three factors of influence: the boundary conditions, the mixture reactivity and the scale are considered together,the mode of the parameters combination was raised,and is obtained equation of the exlposion overpressure of the unconfined gas cloud explosions of built-in semi-spherical-baggy obstructions.Therefore, the basis was provided for the forecast of the scene of the explosion of the flammable gas.