Abstract Rabah Mehaddi

Experimental and numerical study of under-ventilated compartment fires

The presentation will focus on under-ventilated compartment fires, by analyzing the results of an experimental and numerical study about fires issuing from heptane pools and gas burner in a compartment with a door. The key parameters of such a study are the ventilation factor (based on the door height and its area) and the pool fire diameter. The under-ventilated combustion regime results in the appearance of external flames. A series of measurements have been done to identify the conditions that separate the two regimes. Then, in the case of the under-ventilated regime, the fire Heat Release Rate (HRR) was split into two parts: HRRin released inside the compartment and HRRout released outside the compartment. To quantify both quantities, we developed new experimental techniques combining temperature measurements inside the compartment, radiative heat fluxes measurements outside the compartment and cameras that record the flame shape outside the compartment. In addition, we also carried out measurements of the mass loss rate of the heptane fuel by using mass balance and CO and CO2 concentrations. All these quantities have been compared to dedicated numerical simulations carried out with the CFD code Fire Dynamics Simulator. These comparisons reveal the limitation of the CFD modelling and open new perspectives for its evolution.