CONTROL OF FLAME TRANSMISSION FROM A VESSEL TO A DISCHARGE DUCT

摘要

A solution allowing quiet evacuation of gases in a vented explosion propagating from a vessel into a discharge duct has been studied. It consists in placing a wire-net insert at the duct entrance in order to delay flame penetration into the duct and prevent the occurrence of a secondary explosion. Experimental results demonstrate that the secondary pressure rise in the vessel is due to the turbulent combustion of pockets of unburned gases that are "trapped" in corners of the vessel, near the duct entrance. Addition of the insert promotes slow combustion of these trapped gases, preventing the re-augmentation of the vessel pressure. Effect of the insert is studied by a numerical model, based on the "nodal method." The insert is treated as only a heat absorber. Parametric study of the influence of the heat transfer coefficient h indicates that an adequate choice of insert characteristics is able to decrease the temperature of burnt gases and allow flame quenching.