An emergency response model for the formation and dispersion of plumes originating from major fires (BUOYANT v4.20)

Abstract

Abstract. A mathematical model called BUOYANT has previously been developed for the evaluation of the dispersion of positively buoyant plumes originating from major warehouse fires. The model addresses the variations of the cross-plume integrated properties (i.e., the average properties along a trajectory) of a rising plume in a vertically varying atmosphere and the atmospheric dispersion after the plume rise regime. We have described in this article an extension of the BUOYANT model to include a detailed treatment of the early evolution of the fire plumes before the plume rise and atmospheric dispersion regimes. The input and output of the new module consist of selected characteristics of forest or pool fires and the properties of a source term for the plume rise module, respectively. The main structure of this source term module is based on the differential equations for low-momentum releases of buoyant material, which govern the evolution of the plume radius, as well as velocity and density differences. The source term module is also partially based on various experimental results on fire plumes. We have evaluated the refined BUOYANT model by comparing the model predictions against the experimental field-scale data from the Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment, RxCADRE. The predicted concentrations of CO2 agreed fairly well with the aircraft measurements conducted in the RxCADRE campaign. We have also compiled an operational version of the model. The operational model can be used for emergency contingency planning and the training of emergency personnel in case of major forest and pool fires.