%0 Journal Article
%T Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors
%A N. Cai
%A W. K. Chow
%J International Journal of Chemical Engineering
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/910869
%X Heat release rate (HRR) of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD) in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS) version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors. 1. Introduction There are many big construction projects [1] with difficulties to comply with the fire codes while developing in the Far East. Performance-based design (PBD) was then applied to determine fire safety provisions. However, budget allocated on fire safety used to be small, resulting in a lack of full-scale burning tests to measure heat release rate. There are even no resources allocated in some places like Hong Kong to compile a database of heat release rate for local products including train compartments of the railway system [2] as in Japan, China, and Korea. Consequently, wrong concept was adopted in estimating the heat release rate, taking ˇ°average valueˇ± as ˇ°peak valueˇ± in many projects submitted to be evaluated by the principal author [1]. At most, computational fluid dynamics (CFD) was applied [3, 4] in hazard assessment. Fire behavior involves complex dynamics driven by critical events, such as the ignition of secondary items, flashover, window breakage, and falling down of glass systems. All these phenomena have not yet been modeled realistically without using empirical parameters. Authorities having jurisdictions (AHJ) are now more knowledgeable in fire science and engineering. Taking Hong Kong as an example, a huge percentage of senior officers approving fire projects are well trained and
%U http://www.hindawi.com/journals/ijce/2012/910869/