Multiphase CFD modelling for enclosure fires—A review on past studies and future perspectives

Modern buildings and structures are commonly equipped with fire safety detection and protection systems. Owing to the complexity in building architectures, performance-based fire engineering designs are often applied to achieve safety compliance criteria in stipulated fire events. With the uprising popularity of computer simulation fire predictive models benefited by the rapid improvement in computing speed and modelling techniques, the use of computational fluid dynamics (CFD) based fire field models has become an integrated component in fire tenability and assessment studies. This article delivers a comprehensive review on the history, past developments, and current state-of-the-art of CFD models for enclosure fires, as well as providing an in-depth review on the advancement in other sub-modelling components including turbulence, combustion, radiation, and soot models. Additionally, two types of multiphase modelling approaches involving solid-gas and liquid-gas phase models are reviewed. As for the preceding, the consideration of the solid phase combustibles is generally achieved via pyrolysis modelling under the context of CFD. Recent advancements in CFD-based pyrolysis studies are extensively discussed, including the consideration of porous media, charring layer formation, and kinetics search algorithms to describe the solid decomposition and charring processes. Meanwhile, fire suppression models involving the discrete phase model (DPM) approach are reviewed. This includes previous developments in simulation methods of water droplets, coupling approaches with the fire dynamics in the large eddy simulation (LES) framework. Finally, a future perspective regarding the need to develop a melting/dripping sub-model for building materials is discussed, whose reaction kinetics can be supported by molecular dynamics (MD). © 2021, Tsinghua University Press.