Ferrara G, Di Benedetto A, Salzano E, Russo G
Dipartimento di Ingegneria Chimica, Università Federico II, P.le Tecchio 80, Napoli, Italia.
J Hazard Mater. 2006 Sep 21;137(2):654-65. doi: 10.1016/j.jhazmat.2006.03.037. Epub 2006 May 3.
Vent devices for gas and dust explosions are often ducted to safe locations by means of relief pipes. However, the presence of the duct increases the severity of explosion if compared to simply vented vessels (i.e. compared to cases where no duct is present). Besides, the identification of the key phenomena controlling the violence of explosion has not yet been gained. Multidimensional models coupling, mass, momentum and energy conservation equations can be valuable tools for the analysis of such complex explosion phenomena. In this work, gas explosions vented through ducts have been modelled by a two-dimensional (2D) axi-symmetric computational fluid dynamic (CFD) model based on the unsteady Reynolds Averaged Navier Stokes (RANS) approach in which the laminar, flamelet and distributed combustion models have been implemented. Numerical test have been carried out by varying ignition position, duct diameter and length. Results have evidenced that the severity of ducted explosions is mainly driven by the vigorous secondary explosion occurring in the duct (burn-up) rather than by the duct flow resistance or acoustic enhancement. Moreover, it has been found out that the burn-up affects explosion severity due to the reduction of venting rate rather than to the burning rate enhancement through turbulization.
用于气体和粉尘爆炸的通风装置通常通过泄压管道输送到安全位置。然而，与简单通风的容器相比（即与没有管道的情况相比），管道的存在会增加爆炸的严重程度。此外，尚未确定控制爆炸剧烈程度的关键现象。耦合质量、动量和能量守恒方程的多维模型可能是分析此类复杂爆炸现象的有价值工具。在这项工作中，通过基于非定常雷诺平均纳维-斯托克斯（RANS）方法的二维（2D）轴对称计算流体动力学（CFD）模型对通过管道通风的气体爆炸进行了建模，其中实施了层流、小火焰和分布式燃烧模型。通过改变点火位置、管道直径和长度进行了数值试验。结果表明，管道爆炸的严重程度主要由管道中发生的剧烈二次爆炸（燃尽）驱动，而不是由管道流动阻力或声学增强驱动。此外，已经发现燃尽由于通风率降低而影响爆炸严重程度，而不是通过湍流提高燃烧速率。
