Soumbedjioune tunnel in dakar: a case study for CFD modeling of fire-smoke extraction in a sinusoidal floor tunnel

Abstract

Despite numerous studies on fires, each simulation faces several limitations. Fire is a complex phenomenon, and some of its processes remain poorly understood. Furthermore, the progression of flames and smoke is influenced by turbulent flow phenomena. In this context, this article delves into the analysis of smoke flow behavior using numerical fluid dynamics simulations (CFD) with the assistance of ANSYS FLUENT. The primary focus lies in describing the longitudinal ventilation system, a critical element for fire management. The chosen study area is the Soumbédjioune tunnel located in Dakar, Senegal, characterized by a sinusoidal floor with an amplitude equivalent to one-third of the entrance height. The tunnel has dimensions of 300 meters in length (L), 10.5 meters in width (l), and 7.22 meters in height (H). To simulate the source of heat and smoke, a 2-cubic meter fire was placed in the center of the tunnel, modeling the combustion of N₂, H₂O, and O₂ gases at a high temperature of 926.85 degrees Celsius. The simulations yielded a critical ventilation velocity of 5.8 meters per second, a crucial piece of information for fire management in this specific context. Furthermore, this article extends its analysis by examining the evolution of temperature and velocity contours in both ventilated and non-ventilated conditions, providing a deeper understanding of the underlying mechanisms at play.