Abstract：To reveal the relationship between fire, gas, and pressure of gas explosion, with kinds of different length of gas accumulation and ignition strength, the pressure, gas and flame propagation velocities in a tube were measured to study the characteristics of detonation.The results show that the flame propagation speed is much less than the state of detonation flame propagation speed.Flame propagation change trend is linear.The size of the gas explosion flame propagation velocity directly influence detonation, as well as the explosion intensity and the transmission distance.The distance of flame and gas propagation are equal under the condition of gas deflagration that is about 2 times of the total length of original gas accumulation.But their propagation distance is greater than the original gas accumulation length, the propagation distance is uncertainty.

Keyword：confined space;gas explosion;flame;noxious gas;