The objective of this study is to examine the feasibility of two combustion models combined with a large-eddy simulation for a full-scale ventilated tunnel fire. The numerical model solves 3D, time-dependent Navier—Stokes equations, coupled with submodels for soot formation and thermal radiation transfer. Turbulent combustion process is modeled by an eddy dissipation concept (EDC) and mixture fraction (MF) approach by using two chemical reaction steps to CO prediction. The predicted temperature in the smoke and flame shape was compared through a Blind method to the experimental data of Apte et al. [Apte VB, Green AR and Kent JH. Pool fire plume flow in a large-scale wind tunnel. Proceedings of the Third International Symposium on Fire Safety Science, July 8-12, Edinburgh, UK: Elsevier; 1991, pp. 425—434] and Fletcher et al. [Fletcher DF, Kent JH, Apte VB and Green AR. Numerical simulations of smoke movement from a pool fire in a ventilated tunnel. Fire Safety J 1994; 23(4): 305—325]. The predicted results of Fletcher et al. [Fletcher DF, Kent JH, Apte VB and Green AR. Numerical simulations of smoke movement from a pool fire in a ventilated tunnel. Fire Safety J 1994; 23(4): 305—325] with k-ε model and of Gao et al. [Gao PZ, Liu SL, Chow WK and Fong NK. Large eddy simulations for studying tunnel smoke ventilation. Tunn Undergr Sp Tech 2004; 19(6): 577—586] with large-eddy simulation, both based on a single chemical reaction, are also included. Two boundary conditions, such as adiabatic wall and heat loss inside wall, were applied on the tunnel structure. Both the EDC and MF approaches are shown to possess the ability to predict the general behavior of the experimentally determined temperature field as the heat loss inside the tunnel walls is taken into account. While, it is felt that EDC is more convenient for simulation of a large-scale under-ventilated tunnel fire where the CO and soot yields required by using MF approach, vary significantly with the air to fuel ratio by mass.

Current study focuses to the application of an advanced physics-based (reaction–diffusion) fire behavior model to the fires spreading through surface vegetation such as grasslands and elevated vegetation such as trees present in forest stands. This model in three dimensions, called Wildland Fire Dynamics Simulator WFDS, is an extension, to vegetative fuels, of the structural FDS developed at NIST. For simplicity, the vegetation was assumed to be uniformly distributed in a tree crown represented by a well defined geometric shape. This work on will focus on predictions of thermal function such as the radiation heat transfer and and thermal function for diverse cases of spatial distribution of vegetation in forest stands. The influence of wind, climate characteristics and terrain topography will also be used to extend and validate the model. The results obtained provide a basis to carry out a risk analysis for fire spread in the studied vegetative fuels in the Mediterranean forest fires.

This paper aims to study the influence of the tunnel portal designs, wind conditions and ventilation rate on the amount of air pollution short circuit from one tunnel tube to the other. These effects are investigated by Computational Fluid Dynamics (CFD) code used a Large Eddy Simulation (LES) method to control air quality inside the tunnel and reduced as far as possible a short circuited (flow Recirculation) flow level. A validation of CFD code to experimental data in 1:100 scale model of the road traffic tunnel tested in wind-tunnel showed that the CFD gave satisfactory prediction of the air pollution short circuit in the vicinity of tunnel portal. The predicted concentration of the gas tracer (CO₂) used as the safety criterion provide the useful information about a short circuit amount resulted for each structural variant of tunnel portals, such as a central dividing wall built as extensions from the end of road tunnel and offset tunnel portal entrance exit tested under different speed ratio of wind and ventilation. A detailed look at results is beyond the scope of analysis to determine optimal air pollution short circuit percentages. Finally, the perfect tunnel portals geometry can be suggested.

The Fire Dynamics Simulator (FDS) model was utilized in this study to replicate a full-scale aircraft postcrash experiment conducted within the C-133 test facility by the Federal Aviation Administration. FDS is a computational fire field model that incorporates submodels for soot formation, pyrolysis, and thermal radiation transport. It solves three-dimensional time-dependent Navier–Stokes equations and is grounded in the large-eddy simulation approach and the eddy dissipation concept, serving as turbulence and combustion models. The obtained results, including the heat release rate and temperature, were validated against experimental data and compared with earlier prediction studies employing different turbulence and combustion models. The results from this simulation closely align with the experiment’s findings. The impact of fire-blocking layers and carry-on baggage on interior material was examined. Moreover, two boundary conditions were imposed on the fuselage structure: 1) the adiabatic wall, and 2) heat loss within the wall. Both the fire-blocking layers and the adiabatic boundary condition played a significant role in the flashover occurrence. The large-eddy simulation and eddy dissipation concept approaches have demonstrated a reliable ability to predict flashover and general fire properties to a considerable extent.