Flickering Behavior of Turbulent Buoyant Fires Using Large-Eddy Simulation

Abstract

A numerical study investigating the flickering behavior of a turbulent buoyant fire is conducted using large-eddy simulation to examine coupled turbulence, combustion, soot chemistry, and radiation effects. The three-dimensional, Favre-filtered, compressible mass, momentum, energy, and mixture fraction and its scalar variance conservation equations are closed using the Smagorinsky subgrid-scale (SGS) turbulence model. A two-stage predictor-corrector methodology for low-Mach-number compressible flows is adopted. Formation of large-scale vortical structures is well captured, with the predicted puffing frequency agreeing closely with experimentally determined frequencies. Comparisons of instantaneous, mean, and root-mean-square quantities also show qualitative agreement against other experimental data.