Experimental Study On Explosion Impulse Field Of Flammable Gas Cloud Built-in Obstructions

Two main destruction modes for buildings result from the blast wave caused by the unconfined flammable gas explosions are pressure destruction and impulse destruction. It is important to study the influence of obstructions on the impulse of gas explosions for advancing the feasible measures to prevent or restrain the damages.(1) In this paper, an unconfined flammable gas cloud explosion field test system consisting of pressure transducers, data acquisition card, computer and electric spark ignition device was designed, and a large number of flammable gas deflagration experiments were carried out. Through mass spectrum chromatographic analysis of the concentration of the mixed gas cloud of acetylene-air, the extreme explosion overpressure caused by mixture concentration was confirmed as 13.3%. With a view of accident, all other experiments were produced under this premix concentration.(2) Through the analysis of perpendicular experiments, three characteristic parameters of bar grating obstructions (the radius of the obstructions r, the width of space b0 and the width of the bar grating b) and two characteristic parameters of spherical obstruction (the radius of the obstructions r and central angle α) play very prominent influences on explosion impulse.(3) Through large numbers of single factor experiment of characteristic parameters of obstructions, synthetically regression analysis and square deviation analysis, The results show that explosion impulse I is proportional to the radius of the bar grating obstructions r and the cube radix of baffle rateθ, and inversely proportional to the six hypo-power radix of the width of the bar grating b, and is proportional to the radius of the spherical obstructions r and the six hypo-power radix of the baffle rateθ'.(4) Based on large numbers of experiment data, introducing the idea of Multi-energy model and considering the boundary condition, mixture active and scale proportion factor, the explosion impulse fitting equation is obtained, which could be suitable for the other instances.(5) Applying the Neural Network to the simulation of gas cloud deflagration, the forecast values have agreement with the experiment data. This provide a good method for forecastingthe deflagration impulse value.The innovations of this paper are as follows:(1) The impulse field of premixed flammable gas cloud explosion induced by obstructions was researched systematically by means of experiments. Based on the regression of experimental data and deviation analysis, the quantitative fitting equation is obtained between the dimensionless explosion impulse and its influential factors.(2) The idea of the Multi-energy method was applied in the analysis of gas cloud explosion field. Through the parameters combination of three factors of influence, namely the boundary conditions, the mixture reactivity, and the scale, a general fitting equation of explosion impulse is gained, which might be applied to predict other gas cloud explosion impulse field induced by other obstructions.(3) The Neural Network technology was applied in the forecast of deflagration impulse for the first time and gained good effects.