International Journal on Engineering Performance-Based Fire Codes, Volume 7, Number 2, p.35-56, 2005 35 REVIEW OF MODELING FIRE SUPPRESSION BY WATER SPRAYS BY COMPUTATIONAL FLUID DYNAMICS B.H. Cong and G.X. Liao State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China W.K. Chow Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China (Received 20 October 2003; Accepted 27 November 2003) ABSTRACT Water-based fire control systems such as sprinkler are widely used in providing safety. In addition to following the prescriptive codes without understanding the physics behind, more quantitative approaches such as numerical modeling for evaluating the system performance were carried out for new designs. Note that performance-based fire codes might be necessary for some applications. Numerical modeling also contributes to the understanding of the fire extinguishment mechanisms. One of the popular models is Computational Fluid Dynamics (CFD). However, in comparing with applications to simulate fire growth, spread and smoke movement, CFD has not yet been applied extensively to study the fire suppression process or used as a practical design tool. This paper is to review the current developments in using CFD for simulating fire suppression with water sprays. The aim is to provide a broader view on how CFD can be applied for such a study. Fundamental theories for fire field models will be presented in this paper first. Turbulence, combustion, radiation and chemistry models in application to fire modeling are discussed. More advanced but less applied CFD techniques such as Large Eddy Simulations (LES) will be briefly introduced. Also, water spray models available in the literature are discussed in detail. Two different droplet tracking methods − Eulerian- Lagrangian method and Eulerian-Eulerian method are reviewed. Key issues of fire extinguishment criteria for different scenarios are analyzed. Moreover, CFD modeling of suppressing solid fuels by water sprays, current trends and potential applications of CFD in fire suppression modeling are highlighted. Finally, needs for an extensive study on model development and validation studies are pointed out. 1. INTRODUCTION Water has been used for controlling fires since the ancient time. That is because water is readily available and inexpensive in most areas. It is nontoxic, and can absorb large amount of heat due to its latent heat of vaporization and high specific heat capacities in both liquid and gas phases. There are two methods of applying water for firefighting, i.e. jet branch and spray branch. Bulk liquid is applied in the jet branch to cool down the flame and the burning surface using hosereel or fire hydrant systems. Other means such as pouring a basin of water into the fires can also be classified under this method. Large amount of water would be wasted and lead to severe water damages, though jet branch can ‘prewet’ the combustible surface to prevent the ignition. As evaporation can only occur at the liquid surface, it appears that, in theory at least, producing water sprays to extract heat is more desirable for firefighting. In practice, automatic sprinkler system and fixed water spray system are used as fire services installations. Fire suppression with water sprays is reviewed by Grant et al. [1]. Although water spray systems such as automatic sprinkler have been developed and installed for many years, there are stringent requirements to develop a quantitative approach to evaluate the performance of water spray system under different fire scenarios while implementing performance-based code design. However, carrying out full-scale burning tests is very expensive. Experiments on scale models are restricted by the scaling laws, only good enough for studying smoke movement. On the other hand, Computational Fluid Dynamics (CFD) is now a practical fire engineering tool. There are numerous studies on fire growth, spread and smoke movement reported in the literature. Some of the models [2-5] are validated with experimental data and demonstrated to be successful in predicting smoke movement in rooms, tunnels and warehouses. But this technique is not yet practical for modeling fire suppression. There had been some progress in applying CFD for modeling fire suppression due to the increase in