Experimental research into effects of obstacle on methane–coal dust hybrid explosion

An experimental system including pressure transducer, data acquisition card, computer and electric spark ignition device was set up to research methane–coal dust hybrid explosions in closed tubes with different types of obstacles inside. Its dynamic response time was less than a millisecond and the test precision was 0.1%. The experimental results show that the obstacles had great effects on the explosion characteristics in the tube. Hollow obstacles linked with inner wall of the tube induced faster pressure rising than installed center blocked solid obstacles. Obstacles with more sharp corner induce more violent explosions. The most dangerous explosion occurred when spacing between obstacles almost equaled the inner diameter of the tube for the same size obstacle.

► We did methane–coal dust explosion experiments in a closed pipe with obstacles.
► The obstacles have no effects on maximum explosion pressure.
► The obstacles make the maximum pressure rise rate increase dramatically.
► The circumstantial obstacles with a space of pipe inner diameter are most dangerous.
► The maximum pressure rise rate reaches peak when the baffle ratio is 50%.