Numerical simulation of flame propagation characteristics of coal-dust explosion in horizontal pipeline space

In order to research flame propagation characteristics of coal-dust explosion in horizontal pipeline space, based on coal-dust explosion experimental equipment with horizontal glass pipeline, mathematical models of flame propagation characteristics of coal-dust explosion and geometry model of horizontal pipeline were constructed taking lignite as research object, and numerical simulation method was used to research flame propagation characteristics of coal-dust explosion along pipeline length direction (z direction) in horizontal pipeline space at different time and flame temperature propagation characteristics along z direction and in different cross-sections when explosion reaction was sufficient. The research results show: ① The maximum error between simulated value of explosion flame propagation distance and the measured one is 0.09 m at different time, and the minimum error is 0.01 m, which verifies feasibility of the numerical simulation method. ② When coal-dust explosion reaction is sufficient, the horizontal pipeline space can be divided into initial dusting zone of z=0-0.1 m, high temperature ignition zone of z=0.1-0.3 m, temperature jump zone of z=0.3-0.56 m, high temperature core zone of z=0.56-0.86 m and high temperature diffusion zone of z=0.86-1.4 m. ③When coal-dust explosion reaction is sufficient, in cross-section at z=0.2 m, the closer the location is to circle center, the lower the temperature at the location is, which indicates that the region is explosion source, but it is not core area of explosive heat release. There are narrow annular low temperature zones of about 500 K in the outermost peripheral wall region of cross-sections at z=0.2 m and z=0.4 m, which are due to constant pipeline wall temperature of 300 K.In cross-section at z=0.86-1.4 m, the closer the location is to circle center, the higher the temperature at the location is, and the farther the cross-section is away from high temperature core zone, the lower temperature is. The numerical simulation results are consistent with actual flame propagation.