Experimental Investigations on External Flow Field in Explosion Venting

Explosion venting is one of the widely applied protective techniques in industry. Under certain conditions, secondary explosion may happen in the external flow field during venting. Therefore it is highly important to investigate the characteristics of the external flow field, especially the mechanism of the production of the secondary explosion. Detailed studies on the explosion venting to the air were performed by a series of venting tests in a 0.00814m~3 cylindrical vessel connected to a duct under different venting conditions. The sequential shadowgraphs and pressure-time histories of the external flow field were acquired in the tests. These results depict clearly the characteristics of the external venting flow filed and the production and development of the secondary explosion. Moreover, variations of the peak pressure of the secondary explosion were discussed in detail, based on the experimental results under the different venting conditions (i.e. different failure pressure, different vent area, different equivalence ratio of the CH_4-air and different locations of the ignition source).