Experimental Study On The Gas Explosion Suppression By Ultrafine Powder In Tube

As the depth and the production increasing in coalmine,the production safety isvery severe.The gas explosion as one of the major disatsters in coalmine brought thegreater dangers and devatating.That isn`t only caused the casualties,and also theproperty loss.How can reduce effectively the hazards of the gas explosion,and how canlimited its damage scope,which have been valued by scholar at home and abroad.This paper discusses the researches at home and abroad of the gas explosionmechanism, the its suppression measures, and the feasibility of ultrafine powder inhibitgas explosion.The experiments have selected Al（OH）<sub>3</sub>、Mg（OH）<sub>2</sub>、CO（NH<sub>2</sub>）<sub>2</sub>as the gasexplosion suppression powders. It works on the thermal characteristics of the differentgas explosion suppression powders and powders with different particle sizes. Themechanism of the three powders suppression has been discussed, and gas explosionsuppression experiments carry out on the self-built experiment system.The study has found that the added Al（OH）<sub>3</sub>、Mg（OH）<sub>2</sub>、CO（NH<sub>2</sub>）<sub>2</sub>powders aftergas explosion, flame propagation and pressure changes produced different effects.Among the three materials, CO（NH<sub>2</sub>）<sub>2</sub>has the greatest explosion suppressionperformance，its explosion flame velocity peak reduces to31.56m/s, the maximumpressure drops to0.547MPa. Explosion suppression performances have ordered asreduction: CO（NH<sub>2</sub>）<sub>2</sub>>Al（OH）<sub>3</sub>> Mg（OH）<sub>2</sub>. On the other hand, the affects on theexplosion suppression performance of the particle sizes have also been studied. Theparticle size of15μm,25μm,50μm Al（OH）<sub>3</sub>,and the particle size is2.6μm,23μm ofMg（OH）<sub>2</sub>powder are as research objects. The flame propagation speed and themaximum pressure have the greatest decrease after the15μm Al（OH）<sub>3</sub>sprayed. The2.6μm Mg（OH）<sub>2</sub>powder has the better effect than23μm Mg（OH）<sub>2</sub>`s. The experimentalresults show that: The same powder in the case of smaller particle size has the better gasexplosion suppression performance than that of larger particle size.On the basis of the thermal characteristics of the explosion suppression powders,the explosion suppression performances of the different materials and the differentparticle sizes have been discussed. It has a guiding significance for the further study ofgas controlled blasting techniques and materials.