Abstract:In order to study the propagation laws of gas explosion in the T-shaped pipe under different enclosed conditions,the gas explosion experiments were carried out in 90° bifurcated pipe,and the enclosed conditions of pipe were the weak closure (double PVC film weak closure) and the strong closure (straight pipe closure or branch pipe closure).The results showed that when the gas concentration was 9.5%,the oscillation amplitudes of gas explosion pressure,flame propagation velocity and flame front at each point in the pipe were the largest,followed by 11%,and that of 8% was the smallest.In the T-shaped pipe,the gas explosion pressure at the weak closure end decreased continuously.The flame propagation velocity increased slowly at first,then decreased,and then increased rapidly.At the strong closure end,the gas explosion pressure increased,the flame propagation velocity increased slowly at first and then decreased slightly,and increased rapidly and then decreased sharply,and even the flame front oscillated.The maximum gas explosion pressure and flame propagation velocity of each measuring point in different enclosed pipes were compared,and the sequence was: straight enclosed pipe > double PVC film weak enclosed pipe > branch pipe enclosed pipe.