On the Numerical Modeling of Buoyancy-dominated Turbulent Fires by Using Large Eddy Simulation

摘要

This study concerns the modeling of three characteristic buoyancy-dominated turbulent diffusion flames such as pool-like, vertical and interaction between pool-like and vertical wall fires. Controlling mechanisms of three dimensional flow, combustion, soot production and radiation are coupled with a Large Eddy Simulation (LES). An Eddy-Break-Up concept which accounts for the interaction between combustion and turbulence, is implemented in LES. The numerical models have been validated using experimental data from three turbulent diffusion flames. The predicted mean temperature, velocity and total heat feedback from the high temperature gases in the flame to the wall surface follow closely to the experimental data. Moreover, it is found that LES successfully predicted the important features of highly oscillating buoyancy-controlled pool-like fire (recirculation zone, narrowing and broadening of the flame). While, the standard Smagorinsky sub-grid scale model should be improved to predict the variation of the fluctuating velocity and temperature for the vertical wall fires.