Study of critical velocity and backlayering length in longitudinally ventilated tunnel fires

Li, Ying Zhen; Lei, Bo; Ingason, Haukur

doi:10.1016/j.firesaf.2010.07.003

Cited by 421 publications

(279 citation statements)

References 17 publications

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“…The Reynolds number is not conserved in the different scales. Previous studies by the authors have, however, proved that model-scale studies can give interesting results and give important information on fire behaviours under different conditions [7][8][9][10][11][12][13][14][15]. Table 1.…”

Section: Scalingmentioning

confidence: 99%

Fire development in different scales of train carriages

Li¹,

Ingason²,

Lönnermark³

2014

Fire Saf. Sci.

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A fire development analysis of three series of train carriage fire tests in different scales was carried out. These train carriage fire tests included 1:10 model scale tests, 1:3 model scale tests and 1:1 full scale tunnel tests. The heat release rate (HRR) correlations between different scales of carriage fire tests were carefully investigated. The mechanism of fire development is very similar in different scales of tests involving fully developed fires. After the critical fire spread, the fire travelled along the carriage at an approximately constant speed. The maximum heat release rate obtained for a fully developed fire is dependent on the ventilation conditions and also the type and configuration of the fuels, and a simple equation has been proposed to estimate the maximum heat release rate. A global correction factor of the maximum heat release rate is presented and examined.KEYWORDS: train carriage fire, different scales, correlation, fire tests, fire development, local flashover, maximum heat release rate. NOMENCLATURE LISTING

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Section: Scalingmentioning

confidence: 99%

Fire development in different scales of train carriages

Li¹,

Ingason²,

Lönnermark³

2014

Fire Saf. Sci.

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“…For many typical road tunnels, the SCVV is found to be about 3 m s -1 , so many emergency ventilation strategies for longitudinally ventilated tunnels aim to achieve a longitudinal flow of about 3 m s -1 in the event of any fire, in order to control smoke. Ventilation studies since 1995 have tended to build on the work of Oka and Atkinson, adding various complexities relating to features such as tunnel slope [6], aspect ratio [7,8] and the presence of blockages [9,10], and the SCVV concept has become widely accepted in the industry.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Throttling Effect in Tunnel Fires

2015

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Abstract. Critical ventilation velocity remains the most studied phenomenon in the tunnel fire literature. But focus on the velocity as the principal parameter may hide other features of the interaction between a fire and tunnel flow. The throttling effect was identified in the 1960s and described in the 1970s, yet it seems to be generally overlooked these days. In essence, the throttling effect is the tendency of a fire in a tunnel to resist the airflow; the larger the fire, the greater the resistance. Thus, while it has been shown that no increase in longitudinal flow velocity is required to control smoke from fires larger than the 'super critical' limit, in practice, an increasing number of ventilation devices are required to achieve this flow, and hence control the smoke from a fire, as the fire size grows. A CFD modelling study using the FDS model has been carried out to demonstrate this effect. It is clearly demonstrated that for fires larger than the 'super critical' limit, an increasing number of jet fans are required to control the smoke from increasingly larger fires. The results of the modelling study are presented.

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“…Unlike Thomas' correlation, this relation is well known and is often quoted in studies on backlayering and critical velocity [57,63,69]. Equn.…”

Section: Backlayering Lengthmentioning

confidence: 99%

Fires in Ducts: A review of the early research which underpins modern tunnel fire safety engineering

Byrne

Georgieva

Carvel

2018

Tunnelling and Underground Space Technology

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Temperature difference due to stratification (K) ∆ Local gas temperature rise (K) ∆ %&'Average gas temperature rise (K) AbstractMuch of the early research which now underpins tunnel fire safety design was carried out experimentally, using small scale ducts. This paper reviews such experiments, mostly carried out in the 1960s, 1970s, and 1980s, highlighting the assumptions and limitations of the early studies, which may have been forgotten as the equations developed have been applied in practice in the subsequent years. The review covers three primary topics; fire propagation under 'turbulent slug flow' conditions, stratification & flame spread, and backlayering & critical ventilation velocity.

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Study of critical velocity and backlayering length in longitudinally ventilated tunnel fires

Cited by 421 publications

References 17 publications

Fire development in different scales of train carriages

Fire development in different scales of train carriages

Investigating the Throttling Effect in Tunnel Fires

Fires in Ducts: A review of the early research which underpins modern tunnel fire safety engineering

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