Influence of Vent Duct Shape on Explosion Propagation Behaviour of Vented Dust Explosions

Abstract

Dust explosion venting is a common explosion protection measure. In indoor applications, vent ducts in accordance with EN 14491 (2012) are used to direct the explosion safely to the outside. Specific guidance is given in the standard how the vent duct should be designed, mandating area vent duct shape that is equivalent to the vent panel shape. According to EN 14491 guidance, rectangular vent panels should be used with rectangular vent ducts, and circular vents with circular vent ducts, respectively.
In practice, however, rectangular explosion vents are often combined with circular vent ducts allowing more economic and rigid design of the duct. This combination leads to the following differences in comparison to the combination of rectangular vents with rectangular vent ducts:The volume of the vent duct increases, andThe cross-sectional area of the vent duct is larger compared to the area of explosion panel.
These deviations from EN 14491 (2012) guidance may have an influence on the properties of vented explosions.
This study investigates whether the shape of the vent duct affects the reduced explosion pressure p_red while comparing results to calculations according to EN 14491 (2012). Dust explosion tests were conducted for one combination of explosion volume and vent area while varying the following parameters:Vent duct shape;Vent duct length;Vent duct cover.
Experimental results show that the selection of vent duct cover has a significant influence on the reduced explosion pressure ?? ?????? . Overall observations show that EN 14491 (2012) not always yields conservative vent sizing guidance when adapting the shape of the vent duct within the limitations of the present study.