Effect of longitudinal ventilation on heat release rate of tunnel fires

It is very important to accurately predict the fire-induced air velocity, temperature, and smoke concentrations in tunnel fires to design efficient fire protection systems. In this study a scaled model of a tunnel was constructed based on Froude number scaling and wood sticks with different configurations which were burned in a controlled environment. Model vehicles having a square base were built according to the wood crib theory. The impact of varying longitudinal ventilation velocity and the cross-sectional area of the burning substances on the heat release rate and temperature distribution in the tunnel were measured.

Download Full-text

Effect of heat release rate and exhaust vent settings on the occurrence of plug-holing during tunnel fires with two-point extraction ventilation

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2020.103617 ◽

2020 ◽

Vol 106 ◽

pp. 103617

Author(s):

Peng Zhao ◽

Zhongyuan Yuan ◽

Nanyang Yu ◽

Chenchen Liang

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Tunnel Fires

Download Full-text

Research on the maximum fire smoke temperature beneath tunnel ceilings using longitudinal ventilation

MATEC Web of Conferences ◽

10.1051/matecconf/201825102020 ◽

2018 ◽

Vol 251 ◽

pp. 02020

Author(s):

Hui Yang ◽

Bingyan Dong ◽

Sijian Zhang ◽

Dahui Sun ◽

Kirill Lushin

Keyword(s):

Numerical Simulation ◽

Numerical Simulations ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Experimental Results ◽

Small Scale ◽

Longitudinal Ventilation ◽

Fire Smoke

The maximum fire smoke temperature beneath tunnel ceilings using longitudinal ventilation was studied by both small-scale experiments and numerical simulations for a small heat release rate (HRR) fire. And then, the accuracy of the numerical simulation is verified. A numerical simulation is subsequently employed to modify the Kurioka model for cases in large HRR. Then, the modified Kurioka model is verified by various on-site high HRR fire experimental results conducted by other authors.

Download Full-text

Effect of Ventilation and Geometrical Parameters of the Burning Object on the Heat Release Rate in Tunnel Fires

Combustion Science and Technology ◽

10.1080/00102202.2011.625371 ◽

2012 ◽

Vol 184 (2) ◽

pp. 165-177 ◽

Cited By ~ 11

Author(s):

Serkan Kayili ◽

Ahmet Yozgatligil ◽

O. Cahit Eralp

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Geometrical Parameters ◽

Tunnel Fires

Download Full-text

Numerical Simulation and Analysis of Critical Velocity in Tunnel Fires Based on FDS

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.831.455 ◽

2013 ◽

Vol 831 ◽

pp. 455-459

Author(s):

Shu Hui Xu ◽

Ling Fei Cui ◽

Lei Ning ◽

Zi Ye Wang

Keyword(s):

Heat Release ◽

Critical Velocity ◽

Heat Release Rate ◽

Release Rate ◽

Small Scale ◽

Smoke Control ◽

Tunnel Fires ◽

Tunnel Fire ◽

Velocity Prediction ◽

The One

Critical velocity is a very important parameter in smoke control of tunnel fires and the variation of critical velocity against fire heat release rate is also one of the most important issues in tunnel fire researches. In this paper, a simplified physical model of a tunnel was established and the predictions of critical velocity for fire sizes in the 5-100MW range were carried out by FDS simulations. The FDS-predicted dimensionless critical velocities were compared with the values calculated by Wu and Bakar’s model. The result indicated that when the heat release rate was relatively small, Q≤30MW, the critical velocity increased with the increasing of heat release rate and varied as the one-third power of the heat release rate; when Q≥40MW, the growth rate of critical velocity became very small; after Q reach to 60MW, the critical velocity was almost unchanged with the increasing of heat release rate. In addition, the values of critical velocity calculated by Wu and Bakar’model which was derived from small-scale gas fire tests were underestimated. Therefore, the model suggested by Wu and Bakar is not suitable for critical velocity prediction in tunnel fires.

Download Full-text

Effects of ambient pressure on the critical velocity and back-layering length in longitudinal ventilated tunnel fire

Indoor and Built Environment ◽

10.1177/1420326x19870313 ◽

2019 ◽

Vol 29 (7) ◽

pp. 1017-1027

Author(s):

Guanfeng Yan ◽

Mingnian Wang ◽

Li Yu ◽

Yuan Tian

Keyword(s):

Heat Release ◽

High Altitude ◽

Critical Velocity ◽

Heat Release Rate ◽

Release Rate ◽

Ambient Pressure ◽

Smoke Movement ◽

Tunnel Fire ◽

Longitudinal Ventilation ◽

High Altitude Area

Nowadays, the critical velocity and back-layering length are the key parameters in longitudinal ventilation design. However, most studies research them at standard air pressure but ambient pressure decreases at high-altitude area and the reduced ambient pressure could affect the smoke movement characteristics in a tunnel fire. In order to investigate the effect of ambient pressure on the velocity and back-layering length in longitudinal ventilated tunnel, theoretical analysis was carried out first and a series of numerical simulation were conducted with varying heat release rate and ambient pressure. Results show that Li’s model is also reliable under various ambient pressures. The critical velocity under various ambient pressures would become larger with an increase in the heat release rate and would remain stable after the heat release rate reaches a certain value. At smaller heat release rate, the length of counterflow would be higher under reduced ambient pressure while it remains the same when the HRR is large. This could provide reference for tunnel ventilation design at high-altitude areas.

Download Full-text