Properties of Plume and Near Fire Source in Horizontally Long and Narrow Spaces

Abstract

EXperiments were co 皿 ducted to u 皿 derstand the effeCts of a confined space and vcntilation on properties of plume and ncar ficld of fire seurces using 3 types ef model tunnels． The first onc is a scalcd 加 nnel with square and ／ or archod cτoss 凾 section ofO ・ 09 m2 w 醜h 且 ength of rang 洫g from O． 9 to 23mJhe second o 皿e is ， reinforccd concrctc tunmel ， ofO ， 6m wide ， 1． 8m high and 12． 8m long， The last o 皿 e is a fi 」11 ・ scaled tunnel of the cross sectio 皿al area of 5． 4 m2 With arched shape and 400m long． Temperaturcs in thc near field of flame and plume wcre mcasured changing the bulk ventilation yelocity ． Estimation on maxi 皿 um temperature and itS positie ． n that appears in the down ・ flow rcgion and ben。ath the cei g ondcr foroed ventilation wcre modeled ， a 皿 d also medeling on the corrclation fc ｝r the critical velocity was deduccd ． Froudc modeling was utilized on the relations betwecn tho cxcess temperature andlor 叩 ward vclocity along the plume axis under natural ventilation condition and that is ◎ompa 【ed With results obtained in the free beundary condition ．

Air Movement Within Enclosed Road-Objects with Contra-Traffica CFD-Investigation

“…The air-fans, looking towards the eastern exit of the "Vranduk-2" -And while the high temperature-zones of the fire were visible in first sketches, on the iso-surface for the 10m/s, the displayed temperature-zone is fully enveloping the near-fire-place. The accidental thermal load (deep in the sketch) is carried away by the forced air-flow By performing this CFD-based study on covered traffic-objects of the given geometric characteristics within an existing road-infrastructure, the investigation on the accidental fire event was conducted according to the both planned scenarios of several experimental [33,42,44,45] and computer aided [46][47][48] research [49,50] research approaches. A "provocation" to conduct this research, was this specific geometry of the objects of interest, expecting new answers due to the possible impact of a reality-oriented traffic-enclosure (that was imbedded into a computational domain) onto this large-scale combustion and escorting occurrencesThe CFD-demonstration in this attempt, pointed that the geometric characteristic of explored tunnels was not "strong enough" to give major influence to the propagation of the combustion consequences in the first 120s of non-ventilated space -as well as in the case of 120s-long ventilation time of the mentioned caverns.…”

Effect of Shape and Size of a Fire Source on Fire Properties in Vicinity of a Fire Source in a Tunnel

“…Kurioka et al [7] conducted a series of experiments using model tunnels with a rectangular cross section and several aspect ratios in order to create a flowchart for evaluating the extent of damage of tunnel structures caused by undesirable fires in the design stage. They developed empirical formulae to predict and describe not only the flame tilt angle but also the maximum temperature and position of a smoke layer in the presence of longitudinal ventilation.…”