Research on deflagration behavior of gas and gas-coal dust in a vertical pressure relief pipe-line system

Abstract

Gas explosion and gas-coal dust explosion are serious disasters in coal mine production. To further study the hazards of gas explosion and gas and coal dust explosion under different conditions, experiments were done in this paper in a pipe-line system containing an explosion pipe-line and pressure relief pipe-line. Flame propagation behavior and overpressure dynamics of gas explosion and gas coal dust explosion were analyzed. Flame propagation behavior of gas explosion and gas-coal dust explosion are divided into three-stages: spherical flame, round-finger flame, and pointed-finger flame. Flame front position increases with time showing a class exponential growth trend. Flame front velocity has been increasing in the explosion pipe-line. When the flame rushes out of the PVC membrane and enters the pressure relief pipe-line, flame front velocity decreases slightly. The flame front velocity increases rapidly in the pressure relief pipe-line. With growing gas concentration, the peak overpressure in the explosion pipe-line rises at first, then decrease, and the peak overpressure in the pressure relief pipe-line keeps rising. Peak overpressures are obtained at gas concentrations of 9 vol.% and 13 vol.%, respectively. When gas concentrations are 7 vol.% and 9 vol.% in the reaction, the peak overpressures in the pressure relief pipe-line during gas explosion and gas-coal dust explosion are all lower than those in the explosion pipe-line. When gas concentrations are 11 vol.% and 13 vol.% in the reaction, the peak overpressures in the pressure relief pipe-line during the two types of explosions are higher than those in the explosion pipe-line.