A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

Abstract

The mixing of reactants, hot fuel-rich gas and cold air, by a gravity wave, is a complex hydrodynamic process essential in the initiation of hazardous conditions in an under-ventilated compartment fire. The mixing process is first studied by carrying out experiments on a specific enclosure, characterizing the gravity wave by means of particle image velocimetry measurements and fast tomography visualizations. The results are then used to calibrate and validate numerical and CFD models of these experiments. Both numerical and experimental methods permit to determine complex hydrodynamic processes such as Kelvin-Helmholtz instabilities and Van Karman vortices, and to quantify the mixing level in a fire compartment.