Numerical Simulation through Fluent Of a Cold, Swirling Particle Flow in a Combustion Chamber

Abstract

Extended Abstract The study aims to first model the cold, confined and swirling flow in a magnesium burner. One of the most important features of the experimental burner is the presence of a significant recirculation zone, which is crucial for stabilizing the flame in the combustion chamber, [1]. Before modelling the combustion reaction and the flame, a first step is the simulation of the cold monophasic airflow and the accurate simulation of the recirculation zone. To validate the numerical simulations performed with the ANSYS Fluent software, experimental velocity measurements were first made in a 1:1 scale PMMA replica of the experimental burner. A constant temperature hot-wire anemometer was used to determine radial profiles of axial velocity. A low swirl case (S=0.13) was first considered because of its apparent simplicity. Simulation results obtained using different eddy viscosity models were compared to the experimental data and the Standard k-ε model proved to predict the velocity profiles and the central recirculation zone with the most accuracy. A high swirl case was then studied (S=2.94), corresponding to the conditions occurring in the experimental burner. In this case, the turbulence and its anisotropy appeared to be too strong for the eddy viscosity models previously used, and they failed to provide a converging solution. The RSM model was better suited for the task and could predict the position, size and shape of the central toroidal recirculation zone with acceptable accuracy, although important errors were still observed for the velocity values. Part of the inaccuracies could be explained by the usage of first-order