Open Access

ARTICLE

Transient Numerical Analysis of Carbon Monoxide Dispersion in Underground Spaces under Different Ventilation Conditions: A Localized Fire Scenario

M. I. Hernández-López¹, E. V. Macias-Melo², F. N. Demesa-López¹, J. Serrano-Arellano^1,*
1 División de Estudios de Posgrado e Investigación, Tecnológico Nacional de México/IT de Pachuca, Carretera México-Pachuca km. 87.5, Colonia Venta Prieta, Pachuca de Soto, Hgo., México
2 División Académica de Ingeniería y Arquitectura, Universidad Juárez Autónoma de Tabasco (DAIA-UJAT), Carretera Cunduacán-Jalpa de Méndez km. 1, Cunduacán, Tab., México
* Corresponding Author: J. Serrano-Arellano. Email:

Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2026.076455

Received 21 November 2025; Accepted 22 January 2026; Published online 18 February 2026

Abstract

The accumulation of carbon monoxide (CO) in underground spaces poses a significant health hazard; therefore, effective ventilation is essential. This study presents a transient numerical analysis under turbulent flow conditions to evaluate CO dispersion, and identify optimal ventilation configurations. Both during normal operation and in scenarios with high localized concentrations, such as a fire event. The governing equations were solved using the finite volume method with the standard k–ε. Turbulence model. Three configurations were analyzed by varying the outlet location: Case A with an upper-left outlet, Case B with a mid-left outlet, and Case C with a lower-left outlet. The Reynolds number (Re) ranged from 500 to 10,000 to represent different flow velocities. The results showed that the time required to purge the interior region ranged from 11 to 16 s for Re=5000 and Re=10,000, achieving minimum average (CO) concentrations of 1 ppm. Case C exhibited cross-ventilation that enhanced contaminant removal, whereas Case A demonstrated the highest overall distribution efficiency (εC=14.364). In the localized fire scenario, cross-ventilation minimized CO propagation into the interior, with removal times ranging from 11 to 191 s. This depended on the fire location and the Reynolds number. This study demonstrates that outlet positioning, flow velocity, and the presence of thermal plumes significantly influence CO dispersion and removal. The findings provide practical design and operational guidelines for ventilation systems in confined underground environments, ensuring occupant safety and maintaining indoor air quality during both normal and emergency conditions.

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Keywords

Numerical simulation; cross ventilation; carbon monoxide dispersion; localized fire; transient analysis

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