Abstract: In order to study the propagation characteristics of coal dust explosion in the diagonal joint network, CFD was used to simulate the coal dust flame, impact airflow and pressure propagation characteristics of the diagonal joint space. The results show that the explosion reaction tends to be sufficient at 1 s after the coal dust explosion. At this time, the diagonal branch meets the high temperature flame in the ascending space, forming a local high turbulence, and the maximum temperature of the entire space rises to 3 100 K. When the explosion reaction is sufficient, the flame temperature first decreases and then increases in the ascending space. When the explosion reaction is sufficient, the impinging airflow on the z=1.5 m cross section of the breathing zone will be accelerated three times of the airflow at the L- turn near the beginning of the pipeline, at the junction of the upward pipeline and the diagonal joint, and at the T-junction at the end of the pipeline. The local maximum value of the velocity of the impinging airflow at the L-shaped split is as high as 77 m/s. When the explosion reaction is sufficient, the pressure is generally reduced along the direction of the explosion, but the pressure at the junction of the upstream pipe and the diagonal branch is significantly increased. The pressure value at the junction of diagonal joint branch and the upward pipeline is 0.034 MPa greater than the pressure at the junction of the downstream pipeline, which proves that the pressure wave flows from the downward pipeline through the diagonal branch and then passes through the upward pipeline.

Key words:

explosion of coal dust, temperature of flame, propagation characteristic, numerical simulation; diagonal pipe network