Effect of built-in plate obstacle on semi-spherical cloud explosions

An experimental system is set up to study the explosion process of semi-spherical flammable gas clouds built-in plate obstacles. A series of semi-spherical flammable gas cloud explosion tests are carried out with a volume ratio of 7.8% acetylene-air mixture. The pressure-time histories of explosions are recorded by a data-acquisition system composed of pressure transducers, an A/D transformer, a data-acquisition card and a computer, with dynamic responding time less than 0.001s. The experimental results show that the explosion pressure of flammable gas cloud is dependent on the limited extent of plate obstacle to the flame. When the flame interacts with the built-in obstacle, the flame gets bent and the unburned gas forms vortexes behind the plate, which in turn accelerates the flame. The obstacle dimension has important effect on the explosion pressure. The larger the plate radius is, the higher the explosion overpressure is. The position and the hole-interspaced ratio of built-in obstacle influence the flame propagation significantly. When the obstacle limits the flame propagation to the maximum extent, the explosion pressure reaches its maximum value. An equation fitting is gained based on the regressing and square deviation analyses to the experimental results.