An Experimental and numerical study on the combustion characteristics of pool fires in tunnels

Shafee, Sina
This work presents the results of experimental and numerical analysis on tunnel fires in an attempt to improve existing knowledge on the fire dynamics and related safety measures in various tunnel fire scenarios. Results are grouped into four parts in which the effects of tunnel wall coating, inclination, tunnel obstruction and existence of secondary fire source in close vicinity were investigated on tunnel fire characteristics. A 1/13 longitudinally ventilated scaled tunnel model constructed based on Froude modeling was used in the experiments with ethanol pools as the fire source. Numerical simulations were carried out using Fire Dynamics Simulator code. The focus was on critical factors in the safety research community including heat release rate (fire load), burning rate of fire and tunnel temperature distribution, which were measured across a wide range of ventilation conditions, pool size and depth. Results emphasized that the overall variations in the burning rates of fires at different ventilation conditions was a function of competing factors that affect the heat release rate, mass transfer coefficient and cooling effect of the airflow. The application of absorptive wall coating led to considerable reduction of radiative heat flux to upstream of fire. Burning rate and the heat release rate of fire showed an increase as high as 125 % under the effect of the secondary fire source, emphasizing the need to account for possible secondary fires in tunnel safety design. In case of blocked fire tests, the results from experiments as well as simulations indicated that due to changes in local ventilation velocity and flow pattern upstream of the fire, heat release rates tend to increase as high as 0.7 MW/m2 compared to un-blocked fire under certain test conditions. It was also shown that tunnel inclination is an influential parameter that affects the smoke movement and ventilation requirements of tunnel considerably. 


An experimental study on the effects of blockage ratio and ventilation velocity on the heat release rate of tunnel fires
Kayili, Serkan; Yozgatlıgil, Ahmet; Cahit Eralp, O. (SAGE Publications, 2011-8-26)
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-sectio...
An experimental study on the burning rates of interacting fires in tunnels
SHAFEE, SINA; Yozgatlıgil, Ahmet (2018-03-01)
Multiple fires may occur in close proximity in process industries, power generation and fuel storage facilities and confinement conditions such as tunnels, which can lead to a considerable alteration in fire characteristics and safety design. The topic is of significant importance to the fire safety research because there is little work in the literature that investigates the case of interacting fires, which have a destructive potential. In this work, we study the effects of an adjacent fire source on the b...
An analysis of tunnel fire characteristics under the effects of vehicular blockage and tunnel inclination
SHAFEE, SINA; Yozgatlıgil, Ahmet (Elsevier BV, 2018-09-01)
It is known that the blockage and inclination conditions of tunnels are among the important factors affecting fire safety considerations, as these factors could change the characteristics of possible fire incidents as well as smoke movement in tunnels. In the present work, we analyze the variations of the tunnel fire burning rate, heat release rate and smoke backlayering as being functions of these two factors. Ethanol pools were used as fire sources in a reduced scale tunnel model with longitudinal ventila...
Investigation of Combustion Kinetics of Five Waste Wood Samples with Thermogravimetric Analysis
Yorulmaz, Sema Yurdakul; Atımtay, Aysel (2007-02-24)
In the present study, combustion mechanisms, thermal kinetics, and phases of combustion were investigated for untreated pine and treated MDF, plywood and particleboard samples. Waste wood samples were combusted in air at 10, 20 and 30 degrees C/min heating rates in TGA. As a result of TG analysis, thermal decomposition of treated samples was observed at lower temperatures as compared to the untreated pine sample because of the catalyzing effects of the chemicals in the samples. Therefore, there were less fl...
Investigation of the effect of structural damping on wind turbine wind-induced fatigue loads
Kocan, Cagri; Özgen, Gökhan Osman (2022-09-01)
This paper presents a quantitative investigation of the effect of structural damping ratios of the tower and blade vibration modes of wind turbines on wind-induced fatigue loads at critical blade and tower sections. Fatigue loads are used as a relative measure of fatigue life in wind turbine design applications. By increasing the structural damping ratio of each one of the critical structural modes which highly contribute to the overall vibration response, short-term and lifetime fatigue loads at critical t...
Citation Formats
S. Shafee, “An Experimental and numerical study on the combustion characteristics of pool fires in tunnels,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.