Inhomogeneous Hydrogen Deflagrations in the Presence of Obstacles in 25 m3 Enclosure. Experimental Results

Explosion venting is a frequently used measure to mitigate the consequence of gas deflagrations in closed environments. Despite the effort to predict the vent area needed to achieved the protection through engineering formulas and CFD tools, work has still to be done to reliably predict the outcome of a vented gas explosion. Blind-prediction exercises recently published show a large spread in the prediction of both engineering formula than CFD tools. University of Pisa performed experimental tests in a 25 m3 facility in inhomogeneous conditions and with the presence of simple obstacles constituted by plates bolted to HEB beams. The present paper is aimed to share the results of hydrogen dispersion and deflagration tests and discuss the comparison of maximum peak overpressure generated with different blockage ratio and repeated obstacles sets. Description of the experimental set-up includes all the details deemed necessary to reproduce the phenomenon with a CFD tool.