Fire behaviour and external flames in corridor and tunnel‐like enclosures

Abstract

This work investigates how the inflow, the burning and the outflow develop in a corridor open to one end having a fire at either the closed or open end. The situation of a corridor fire having a fire source at the close end is a situation similar to a tunnel having a fire source at the centre of the tunnel without ventilation. A gaseous propane burner is used to produce the fire at a prescribed fuel flow rate in a long corridor of aspect ratio up to 6:1 having a rectangular cross section and varying door‐like openings. Gas temperatures using thermocouple trees, heat fluxes in the corridor and on its façade, flame heights of emerging flames and total heat release rates (HRRs) are measured as the fuel flow rate of propane increases gradually and linearly with time to a preset maximum value. For over‐ventilated conditions, the flames remain near the fire source at the closed end of the corridor. Unexpectedly, it is established for under‐ventilated conditions that the inflow of air is not affected by the aspect ratio of the corridor or the location of the burner in the corridor and that the vertical distribution of gas temperatures inside the enclosure is nearly uniform with height everywhere. In addition, the flame heights and heat fluxes on the façade are the same as those for aspect ratios of the corridor from 1:1 to 3:1 examined in previous work. Moreover, as the conditions changed from over‐ventilated to under‐ventilated conditions, the flames migrated in a ghostly manner from the closed end to the open end of the corridor as soon as under‐ventilated conditions were established. The speed of migration of the flames from the back to the front has also been inferred from the thermocouple tree measurements, which also indicate that the flow conditions ahead and after the passing of the front are changed. These results can be applied to interpret some of the observed behaviours of fires in long corridors or tunnels without ventilation. Copyright © 2012 John Wiley & Sons, Ltd.

Assessment of fire behaviour of high‐speed trains' interior materials: small‐scale and full‐scale fire tests

“…The results of Prof. Delichatsios' studies support those of previous works on long corridors and tunnels. He concluded that the gas flow is controlled by different phenomena, distinguished in terms of the buoyancy source, including the following:horizontal gravity flow at open end of tunnel or corridor ,entrainment requirements of buoyant flow at source ,combustion air requirements of fire source andnature of fuel bed:For a gaseous burner having a fixed fuel‐supply rate, the flames move towards the open end.For solid or liquid fuel, the combustion is local if the spread of fuel is localised.For distributed solid or liquid fuel, the combustion moves towards the front of the fuel .…”

Experimental study on flame merging behaviors from two pool fires along the longitudinal centerline of model tunnel with natural ventilation

“…Its aspect ratio is determined based on a survey of 17 urban road tunnels in Beijing, Nanjing and Shenzhen in China, and is considered to be an extensive representation [30] . The most widely used wall and ceiling materials for model tunnels is the fireproofing board [21,31,32] as it has low thermal conductivity which is a reasonable representative of real tunnel materials. Fireproofing boards of 20 mm thick were used to make the top, bottom and one sidewall of the tunnel while the other sidewall was made of 10 mm thick fire-resistant glass for observation.…”

Designing an experimental rig for developing a fire severity model using numerical simulation

“…Their work 1 proposed a model named the VU model, which can be used for the calculation of the HRR based on the enclosure geometry. They also compared the results of the VU model with that of the Conseil International du Batiment (CIB) model 1,5 Recently, a new version of FDS (version 6) 10 has been released with improved evaporation and combustion sub-models. Therefore, this study aims to redesign the experimental rig in which fire behaviour can be accurately simulated using FDS6.…”

“…A series of small‐scale experiments with various enclosure sizes, locations of fire and geometries of opening were carried out in the study of Beji et al This study measured the HRR and combustion gases under a calorimeter hood as well as the temperature inside the enclosure using thermocouple trees at various locations. It is noted that the inflow rate of air and HRR was only affected by the shape of opening but not the length of the enclosure.…”

“…The oxygen flow rate through an opening will determine the extent of the combustion process and heat release rate (HRR) from the fire in the enclosure. 2 Many previous studies show that the combustion process in deep enclosures is strongly affected by the flow of air coming across the opening (vents) as well as the geometry of the enclosure. For example, the comparison of HRR and fire behaviour in a deep enclosure and a wide enclosure with different opening sizes and shapes are described in a study by Thomas and Bennetts.…”