Abstract: In order to study the influencing factors and mechanism of the function of dust explosion isolation flap valves， the corn starch isolation experiments were conducted based on the 1m³ standard explosion test system and the DN600 flap valve. In addition， the Fluent software was applied to simulate the isolation process of the flap valve at different installation distances. The two-dimensional corn starch dust explosion model was built and the dynamic process of flap closing was solved by the 6 DOF dynamic mesh model. The results show that the pressure development， flame propagation behaviors and flap closing process are consistent with the experiment. Furthermore， the flow velocity distribution in the flow field during the flap closing process is revealed， and the speed of the flap movement is affected significantly by the rising rate of dust explosion pressure. The increasing rate of explosion pressure rise often leads to the increasing closing speed. The backflow behind the valve forms due to the negative pressure， and the minimum installation distance of the DN600 flap valve should be 6 to 7 times of its pipe diameter.

Key words: explosion isolation; dust explosion; explosion isolation flap valve; numerical simulation; corn starch