From small-scale tunnel fire simulations to predicting fire dynamics in realistic tunnels

Longitudinal ventilation is the most popular procedure for ventilating tunnels. It is relevant to understand the interaction between ventilation velocity and tunnel fire dynamics. In this work, we perform sensitivity analysis to quantify the influence of ventilation velocity on the parameters: the maximum ceiling temperature, the maximum floor temperature, the maximum ceiling flux, the maximum flux on the floor and the fire growth rate. We perform numerical simulations in a model scale tunnel. Through Froude scaling, we project results of the small-scale numerical simulations to the realistic size tunnels. A comparison of the extrapolated results to the large-scale experimental data display good agreement. Furthermore, we develop analytical expressions for predicting the maximum ceiling temperature, the maximum ceiling flux and the maximum flux on the tunnel floor during a heavy goods vehicle fire.