Railway is the key transport means in China including the Mainland, Taiwan, and Hong Kong. Consequent to so many big arson and accidental fires in the public transport systems including trains and buses, fire safety in passenger trains is a concern. Numerical simulations with Computational Fluid Dynamics on identified fire scenarios with typical train compartments in China will be reported in this paper. The heat release rate of the first ignited item was taken as the input parameter. The mass lost rate of fuel vapor of other combustibles was estimated to predict the resultant heat release rates by the combustion models in the software. Results on air flow, velocity vectors, temperature distribution, smoke layer height, and smoke spread patterns inside the train compartment were analyzed. The results are useful for working out appropriate fire safety measures for train vehicles and determining the design fire for subway stations and railway tunnels.
Summary Although double‐skin façade (DSF) is an environmental‐friendly architectural feature, its fire behaviour is a deep concern. The interior glass system including the glass pane, metal frame and associated accessories will be hotter than the exterior glass system as demonstrated by earlier studies. The glass pane above the fire room will be broken to spread flame into the upper compartment. Aprons are proposed to protect the air cavity of DSF in a way similar to those outside a single‐skin façade. In this paper, the effect of aprons in protecting against fire spread from an underlying compartment to the compartments above by preventing glass breakage of the inner glass pane was studied. Fire and smoke from a post‐flashover room fire adjacent to the DSF would be trapped in the air cavity between the two glass panes. Spreading of hot gases with different apron widths was studied by numerical simulations with CFD first. Fire environment with and without breaking the apron immediately above the fire room was studied. Full‐scale burning tests on part of an experimental DSF rig were then carried out to demonstrate the performance of horizontal apron in the DSF rig of 6 m tall and air cavity depth of 2 m with different apron widths. All demonstrated that providing apron is appropriate in protecting DSF fires. Copyright © 2014 John Wiley & Sons, Ltd.
Internal fire whirls (IFW) with single corner gap generated in a vertical shaft model were investigated by experiments and numerical simulations. IFW generation process, fuel burning rate and temperature history were studied. Typical transient experimental and simulated flame shape deduced from temperature were studied. The dynamic phenomena of IFW generation and development was captured in both methods. Numerical simulations on medium scale IFW using a fully-coupled large eddy simulation incorporating subgrid scale turbulence and a fire source with heat release rates compiled from experimental results were carried out. Validation by comparing predicted results with experimental data demonstrated that an IFW can be simulated by CFD. Experimental and numerical results for flame surface, temperature, and flame length were in good agreement. IFW flame region and intermittent region were longer than ordinary pool fire. The modified centerline temperature empirical formula was derived.Variations of vertical and tangential velocity in axial and radial directions were shown. The vortex core radius was found to be determined by fuel bed size.
Experiments on fire whirls generated by a gasoline pool fire in a vertical shaft were carried out. Vortex motions of swirling flame induced by buoyancy above the pool fires were observed to be more vigorous with increase in height. Upward flame motions were resulted due to increase in buoyancy. The phenomenon was described mathematically by solving the vorticity transport equation with reasonable assumptions and appropriate boundary conditions. Analysis gave swirling attenuation along the vertical direction. By measuring heat release rates and fire whirl diameters at different heights, vertical variation of circular speeds of fire whirls was derived.
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