Abstract: By using the improved visual Hartmann device,the flame propagation law of HMX dust cloud explosion was studied, and the effects of different HMX dust cloud concentration and particle size on the flame propagation velocity and height of dust cloud explosion were observed. The results showed that, concentration of HMX dust changed from 74.1 g/m³ to 185.1 g/m³, the maximum height of flame propagation increased from 29.97 cm to 60.81 cm, and the maximum velocity increased from 58.91 m/s to 175 m/s. The amplitude of flame fluctuation increased with the increase of concentration, and the flame fluctuation appeared obviously earlier. When the particle size of HMX dust increases from 19.02 μm to 53.56 μm, the maximum height of flame propagation decreases from 55.45 cm to 40.02 cm, the maximum flame propagation velocity decreases from 181.93 m/s to 121.28 m/s, the flame fluctuation amplitude decreases obviously, and the flame fluctuation appears delayed. 

Key words: HMX, flame propagation, amplitude of fluctuation, particle size, concentration