Numerical analysis of influence of various bluff-body shapes on diffusion flame dynamics

Abstract In this paper, various bluff-body shapes (cylindrical, square, star) and two different surface topologies (smooth, wavy) are applied as passive tools for controlling a non-premixed hydrogen flame in combustion chamber. We focus on the dynamics of its time-averaged characteristics close vicinity an injection system within formed recirculation zones also far-field. The research is performed with help large-eddy simulations (LES) method using ANSYS Fluent software high-order academic code SAILOR. Flame behaviour found to be strongly dependent geometry whereas wall topology affects only slightly. cases square star bluff-body, small vortical structures originating at corners deform large created by Kelvin-Helmholtz instability mechanism. This intensifies mixing process and, configuration shape translates shortening zone 15% equivalent diameter flame, which axis develops closer bluff-body. leads most uniform radial border or zone.