Some Tips on Numerical Modeling of Airflow and Fires in Road Tunnels

Król, Aleksander; Król, Małgorzata

doi:10.3390/en14092366

Cited by 3 publications

(2 citation statements)

References 38 publications

(56 reference statements)

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“…During a visit to a mining enterprise in Shanxi Province, a scaled-down model of a roadway section measuring 4 m × 5 m was established. The model was created based on the principles of power similarity and motion similarity in hydrodynamics, ensuring that it was isometrically scaled with the actual model [22][23][24] (pp. 179).…”

Section: Experimental Platform Constructionmentioning

confidence: 99%

“…Zhou Chuang [2] (pp. [24][25][26] and colleagues conducted scaled-down model experiments and numerical simulations to study mine ventilation resistance in the presence of a uniform heat source. By integrating theoretical principles of thermodynamics and the equation of energy conservation, they developed a model for calculating the thermal resistance of a tunnel with a uniform heat source; Li Zongxiang [3] (pp.…”

Section: Introductorymentioning

confidence: 99%

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Research on Resistance Characteristics of Fire Zone of Mine Tunnel Fire and Construction of Calculation Model

Ni,

Zhao,

Wang

et al. 2024

Fire

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To investigate resistance change in the fire area of a roadway caused by roadway fires, a mathematical calculation model for thermal resistance is developed. Theoretical research is conducted to analyze the factors influencing resistance change through theoretical derivation, revealing that temperature is a key factor contributing to the change in thermal resistance. By leveraging the correlation between changes in CO concentration and temperature on the downwind side of the roadway within the fire zone, researchers developed mathematical models to predict temperature increases at various points downwind of the fire source. These models were then used to determine the mathematical relationship governing the change in thermal resistance. The accuracy of the numerical simulation software was validated using Fluent numerical simulation software and scaled-down model experiments. Full-scale numerical simulation experiments were conducted to investigate the fire characteristics of roadway fires and validate the thermal resistance mathematical model. The results indicate that the thermal resistance in the numerical simulation is 7.55 Pa at 20m from the fire source and 5.54 Pa at the end of the roadway. The decrease in resistance is linear. The minimum error between the thermal resistance calculated by the mathematical model and the gradient of the pressure drop in the numerical simulation is 0.03 Pa, approximately 2.3%. Furthermore, the fitting degree of the pressure drop in each section is as high as 97.7%. The calculation model demonstrates high accuracy and offers a theoretical foundation for investigating fire resistance in tunnel fire.

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Section: Experimental Platform Constructionmentioning

confidence: 99%

Section: Introductorymentioning

confidence: 99%

Research on Resistance Characteristics of Fire Zone of Mine Tunnel Fire and Construction of Calculation Model

Ni,

Zhao,

Wang

et al. 2024

Fire

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Improvement of Modeling Velocity of Airflow Created by Emergency Ventilation in a Road Tunnel Using FDS 6

et al. 2023

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Road tunnels are equipped with various safety installations that enable the tunnel’s autonomous response to fire in order to ensure conditions suitable for safe self-rescue and evacuation. A key role in this effort is played by the monitoring of the longitudinal airflow velocity and its regulation. This study contributes to validation of the Fire Dynamics Simulator (FDS 6) capabilities to model tunnel airflow generated by emergency ventilation. A previous study, in which an FDS 6 model of a real 900 m long motorway tunnel was developed and validated by a full-scale ventilation test, pointed to the relatively high inaccuracies of the average steady-state airflow velocity generated by ventilation measured by tunnel anemometers (13%, 17% and 14% for three ventilation modes). In this paper, it is shown that the application of a modified evaluation procedure and improving the representation of tunnel anemometers leads to the significant improvement of simulation results with inaccuracies of 5%, 1% and 3% for the considered ventilation modes. The observed inaccuracies are even comparable to the measurement accuracy of the tunnel anemometers. A further extension of the modeling of the steady-state airflow velocity generated by emergency ventilation measured by the used anemometers is also described.

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Study of Blockage Effects of Metro Train on Critical Velocity in Sloping Subway Tunnel Fires with Longitudinal Ventilation

Wang

Gao

2022

Energies

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Critical velocity is very important for smoke control in longitudinally ventilated subway tunnel fires. Numerical investigations are conducted in this paper to study the impacts of metro train blockages on critical velocity in sloping subway tunnel fires by using fire dynamics simulator (FDS) tunnel models validated with the field-experiment data. Moreover, a global model of critical velocity is presented for the blocked zone of a metro train in subway tunnel fires including influencing factors of the blockage ratio and tunnel slope. The results show that the reduction ratio of critical velocity in the blocked zone is less than the metro-train blockage ratio. The correction factor between the critical velocity reduction ratio and metro-train blockage ratio is 0.545. The aerodynamic shadow zone downstream of a subway train blockage has important impacts on the critical velocity. The critical velocity in the unblocked zone of a metro train is higher than that in the blocked zone of a metro train blockage. The reason is that smoke flow is hindered by the metro train blockage in subway tunnel fires. With an increase in the blockage–fire source distance, the critical velocity first decreases and then tends to be constant. The global model presented can accurately predict the critical velocity in a sloping subway tunnel with a train blockage. The results may provide beneficial suggestions for designing ventilation systems for subway tunnels.

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Some Tips on Numerical Modeling of Airflow and Fires in Road Tunnels

Cited by 3 publications

References 38 publications

Research on Resistance Characteristics of Fire Zone of Mine Tunnel Fire and Construction of Calculation Model

Research on Resistance Characteristics of Fire Zone of Mine Tunnel Fire and Construction of Calculation Model

Improvement of Modeling Velocity of Airflow Created by Emergency Ventilation in a Road Tunnel Using FDS 6

Study of Blockage Effects of Metro Train on Critical Velocity in Sloping Subway Tunnel Fires with Longitudinal Ventilation

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