Experimental Study On The Energy Reduction Of Gas Explosion By Cavity Structure

According to the accident statistics in recent years,about 70%are due to gas explosion when more than 10 people have been killed in coal mines.At present,the most coal mines in China are gas mines,and half of them are high gas and outburst mines.Therefore,in order to achieve safe mining in coal mines,the key prevention and control of gas explosion must be made.The technical measures for suppressing gas explosion and spread contains water bag,water curtain,rock powder shed,dry powder,etc.On the basis,passive technical measures can not cope with the second explosion accident and have poor effect.Active technical measures have many shortcomings,such as,poor stability and low sensitivity and expensive maintenance costs.This makes it difficult to be widely used in coal mine.Therefore,it is urgent to study the prevention and control of gas explosion accidents with new technical measures.This is also great to the safety of coal mines.In this paper,the method of theoretical analysis and experimental study is used to find energy reduction of the gas explosion by the cavity structure.The experimental system of gas explosion uses the large circular tube,which diameter is 200mm and length is 34m.The system is mainly composed of explosion tube network subsystem,data acquisition subsystem,ignition subsystem and ventilation circulation ventilation subsystem.Through analysis,four groups of representative cavity structures named as 300*300*200,300*500*200,500*300*200,500*500*200 are selected.The four groups of cavity structures are used to reduce the energy of gas explosion.It is found that the 500*500*200 cavity structure has the best wave attenuation effect.The cutoff range for the flame front is 16.3%?20.4%and the reduction for the shock wave super pressure is 20.44%?45.8%.Therefore,the 500*500*200 cavity structure is the best cavity.Four groups of experiments are carried out with ABC dry powder and 500*500*200 cavity structure.The dosage of ABC dry powder is 20g,50g,80g and 110g respectively.The experimental results show that the attenuation for experimental flame front is 17.2%,44.3%,71.4%,98.7%respectively and the attenuation for overpressure is 23.9%,51.4%,33.2%and 28.4%respectively.This indicates that the 500*500*200 cavity structure with ABC dry powder has a very prominent reduction effect for the flame front,but not for the shock wave overpressure.In this paper,the energy reduction effect of cavity structure for gas explosion is studied.On this basis,the enhanced reduction experiments are carried out with ABC dry powder.Experimental data and regular conclusions can provide new ideas for reducing gas explosion disasters.It has important scientific and practical significance to preventing and controlling the gas explosion accidents in coal mine.