(120d) Simulation of Explosion Suppression Systems and Extinguishing Barriers Using the Cfd Code Desc

Explosion suppression is a well-established technology for limiting the consequences of dust explosions. The development of explosion suppression systems took place in cubical vessels and near homogeneous fuel-air mixtures, whereas in practical situations both vessel shape and homogeneity of the fuel-air clouds vary considerably. By considering the actual industrial geometry, a properly validated tool based on computational fluid dynamics would allow for optimum design of suppression systems. Furthermore, such a tool could be used to investigate the limits of applicability of a suppression system with specified properties (throw, type of suppressant, response time, etc.) for a given application (reactivity of fuel, volume of vessel, etc.). Extinguishing barriers are often used in combination with explosion suppression systems to prevent flame propagation between connected equipment (explosion isolation). The CFD tool would allow for optimal determination of installation distances for such barriers, taking into account both the application and protective systems on the vessel were the initial explosion arises.

DESC is a CFD code for simulating industrial dust explosions in complex geometries. Although most work with DESC has focused on vented dust explosions, the code also contains models for the effect of suppressant on the burning velocity in dust clouds, and logical functions suitable for simulating the functionality of suppression systems. This paper describes the modelling of suppression systems and extinguishing barriers in DESC, and presents results from the validation work. Possibilities, limitations and future improvements to the modelling approach are outlined.