The deflagration experiments were carried out in the 2000 m experimental base to study the enhancement mechanism of deflagration impulse induced by obstacles.Acetylene-air cloud with a 13.3 %(vol) ratio was used as flammable material

which was restricted with 0.02 mm thick polythene film.Positive and negative impulse of deflagration was acquired by means of calculation with pressure recorded by a data-acquisition system whose dynamic responding time was less than 1 ms.Obstacles were composed of plastic binding strip.A series of experiments was completed to research the relations between impulse and obstacle radius

porous ratio and distance from ignition point.The experimental results showed that the deflagration impulse

either positive or negative

was enhanced by obstacles.The deflagration impulse field approximated to cosine curve distribution.The positive and negative impulses increased with increasing barrier radius and with reducing interspaced ratio.