Effect Of Different Diameter Pipe Or Bend Pipe On Methane Explosion

In the producing process of coal industry, gas explosive accidents happen frequently andcaused tremendous loss of life and property. To ensure coal industry progresses safely, thepropagation rule of gas explosion must be mastered, in addition to strengthening securitymanagement. At present, most research about gas explosion has been done under thecondition of equal diameter pipe, but variable cross-section and bend can be seen everywherein the workings. So studying the gas explosion under this condition is important forpreventing and reducing the hazard.In order to simulate the underground condition more closely, different diameter pipesand bend pipe added on the horizontal pipeline explosion test equipment. In this paper, westudied the effect of the diameter, length and position of different diameter pipes, and theangle, position of bends on the propagation rule of gas explosion. The main results of thispaper are as follows:(1)Compare with the equal diameter pipe, different diameter pipe changed the value ofmaximum explosion pressure and the tendency of flame propagation velocity. The evolutioncurve of maximum explosion pressure assumed a shape of single-peak and three-zone, withthe peak value 0.4041MPa. In the front of the different diameter pipe, flame propagationvelocity changed slightly, however, after the different diameter pipe, the velocity reducedfrom 25.8m/s to 3.5m/s sharply.(2)Under the same experimental condition but changing the diameter from 88mm to108mm, maximum explosion pressure and flame propagation velocity increased. Whilechanging the length from 0.28m to 0.56m, maximum explosion pressure and flamepropagation velocity increased too. When the diameter and length changed at the same time, the variation tendency of the maximum explosion pressure and flame propagation velocityhad a same trend with the diameter.(3)Adding a bend in the equal diameter pipe, the maximum explosion pressure and flamepropagation velocity increased. In front of bend, the evolution rule of the maximum explosionpressure and flame propagation velocity stayed the same with the equal diameter pipe. At thetwo ends of bend, the maximum explosion pressure increased from 0.2931MPa to 0.4717MPa,and the flame propagation velocity increased from 25.8m/s to 101.2m/s.(4)Under the same experimental condition but changing the angle of the bend, at thesame position the maximum explosion pressure and the flame propagation velocity increasedwhile the angle increased. When the angle was 45°, the maximum explosion pressure was0.4834MPa, and the flame propagation velocity was 84.4m/s. When the angle was 90°, themaximum explosion pressure was 0.5461MPa, and the flame propagation velocity was101.2m/s.(5)Under the same experimental condition, when the distance between the differentdiameter pipe or bend pipe and the ignition source increased，the distance between theposition of the maximum explosion pressure extreme value and the ignition source increased,while the distance between the position of the flame propagation velocity accretion extremevalue and the ignition source increased.