Fire plume in a two-layer stratified environment

International audienceThe present work analyses theoretically and numerically fire plumes evolving in a two-layerstratified environment. The ambient fluid consists of a lower cold (heavy) layer and an upperwarm (light) layer with a sharp interface. The fire plume is controlled by the fire heat releaserate Q. Depending on the density interface location Hl and on the fire source conditions,the fire plume can rise indefinitely or can be captured by the density stratification. Todetermine a criterion between these two situations, a theoretical model is proposed. Withthis model, it is found that the trapping/escaping criterion of the fire plume is determined interms of a stratification parameter lambda> C3 where the constant C3 ≈ 0.88. The stratificationparameter is a function of the fire heat release, the density interface location Hl and theambient stratification. Moreover, the model also allows the plume height to be determinedanalytically. The comparison with the numerical data shows an excellent agreement