Simulation of explosion suppression systems and extinguishing barriers using the CFD code DESC

摘要

Explosion suppression is a well-established technology for limiting the consequences of dust explosions. The development of explosion suppression systems took place in compact vessels and near homogeneous fuel-air mixtures, whereas in practical situations both vessel shape and homogeneity of the fuel-air cloud vary considerably. By considering the actual industrial geometry, a properly validated simulation tool based on computational fluid dynamics could allow for more optimum design of suppression systems. With such a tool, engineers could explore the limits of applicability of suppression systems for specified parameters such as volume and shape of process vessels, reactivity of fuel, type of suppressant, response time of the suppression system, throw of dispersion nozzles, etc. Furthermore, the same simulation tool should also be suitable for describing explosion isolation by extinguishing barriers. DESC is a CFD code for simulating industrial dust explosions in complex geometries. Although most validation 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 and extinguishing barriers. This paper describes the current philosophy behind the modelling of explosion suppression in DESC, presents some results from the initial stages of the validation work, and discusses possibilities, limitations, and future prospects for CFD modelling of suppression systems and extinguishing barriers.