Numerical simulations of a methanol pool fire

Simulations of a turbulent methanol pool fire are conducted using both Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) modeling methodologies. Two simple conserved scalar flameletbased combustion models with assumed PDF are developed and implemented. The first model assumes statistical independence between mixture fraction and its variance and results in poor predictions of time-averaged temperature and velocity. The second combustion model makes use of the PDF transport equation for mixture fraction and does not employ the statistical independence assumption. Results using this model show good agreement with experimental data for both the 2D and 3D LES, indicating that the use of statistical independence between mixture fraction and its dissipation is not valid for pool fire simulations. Lastly, "finger-like" flow structures near the base of the plume, generated from stream-wise vorticity, are shown to be important mixing mechanisms for accurate prediction of time-averaged temperature and velocity.