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

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

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

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.

Heat release rate and thermal fume behavior estimation of fuel cell vehicles in tunnel fires

2019 ◽  
Vol 44 (48) ◽  
pp. 26597-26608
Author(s):  
Miho Seike ◽  
Nobuyoshi Kawabata ◽  
Masato Hasegawa ◽  
Hirato Tanaka
Keyword(s):  
Fuel Cell ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fuel Cell Vehicles ◽  
Tunnel Fires

An experimental study on the effects of blockage ratio and ventilation velocity on the heat release rate of tunnel fires

2011 ◽  
Vol 29 (6) ◽  
pp. 555-575 ◽  
Author(s):  
Serkan Kayili ◽  
Ahmet Yozgatligil ◽  
O. Cahit Eralp
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Scaled Model ◽  
Wood Crib ◽  
Cross Sectional ◽  
Tunnel Fires ◽  
Longitudinal Ventilation ◽  
The Impact ◽  
Ventilation Velocity

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.

scholarly journals Numerical Study of the Effects of the Jet Fan Speed, Heat Release Rate and Aspect Ratio on Smoke Movement in Tunnel Fires

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1206
Author(s):  
Ha Thien Khieu ◽  
Young Man Lee ◽  
Ji Tae Kim ◽  
Hong Sun Ryou
Keyword(s):  
Aspect Ratio ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Numerical Study ◽  
Smoke Movement ◽  
Tunnel Fires ◽  
Jet Fan ◽  
Fan Speed ◽  
Set Up

In this study, the effects of the jet fan speed, heat release rate and aspect ratio on smoke movement in tunnel fires have been investigated. The jet fan speed was changed from 6.25 (25%) to 12.5 m/s (50%), 18.75 m/s (75%), and 25 m/s (100%). The heat release rate was set up from 3.9 to 6 MW and 16 MW, the aspect ratio was changed from 0.6 to 1 and 1.5, respectively. The lower the jet fan speed is, the longer the smoke back-layering length is. With a higher velocity, the smoke tends to move out of the tunnel quickly; however, smoke stratification also occurs, and this reduces visibility. This could make it difficult for people to evacuate. With a higher heat release rate, the smoke tends to move far away from the fires quickly when compared with other cases. Additionally, the higher the heat release is, the longer the smoke back-layering is. Finally, with a higher aspect ratio, the smoke back layering length in the tunnel is also longer. The smoke layer thickness is also larger than in other cases. The correlation of velocity, heat release rate and aspect ratio has been investigated to avoid the smoke back layer length in tunnel fires.

Experimental study on heat release rate measurement in tunnel fires

2019 ◽  
Vol 43 (4) ◽  
pp. 381-392 ◽  
Author(s):  
Na Kang ◽  
Yueping Qin ◽  
Xin Han ◽  
Beihua Cong
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Rate Measurement ◽  
Tunnel Fires
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