Development in comprehensive CFD simulation of fire and explosion

Abstract

In this study, an outline of developments is presented in comprehensive computational fluid dynamics (CFD) simulations of fire and explosion with respect to safety science. Fires can be divided into two types: conventional and spontaneous. Conventional fires typically address unwanted combustion in air, whereas spontaneous ignition fires typically address unwanted combustion in porous media. Given that the porous media has a dominant effect on the flow, the behavior of a spontaneous ignition fire completely differs from that of a conventional fire. Although a fire mainly comprises a diffusion flame, where the fuel and oxidant are initially separated, and low-speed flow that can be considered incompressible, explosion usually occurs with premixed combustion, where the fuel and oxidant are initially well-mixed, and high-speed flow where the compressible effect must be included. Owing to the complexity of fires and explosions, a comprehensive CFD simulation should carefully consider turbulence, turbulent combustion, two-phase flow (for cases where liquid droplets and/or solid particles are involved), conjugate heat transfer between gas and solid (including thermal radiation, convective heat transfer, and heat conduction inside solids), and pyrolysis of combustible solids. These interactive processes are also discussed. Furthermore, some developments by the author are presented along with illustrative simulations performed using Simtec software [1], which is used to implement the developments.