Large eddy simulation on swirl direction effect of can type combustor with multi-swirl injectors

Detailed understanding of the flow evolution, fuel/air atomization and mixing, and flame dynamics is critical to the development of high-performance and stable combustion devices. Most existing studies focus on the flow and combustion dynamics of single-element injectors. The interactions among injectors and associated wall coupling were often ignored. The purpose of this study is to conduct a more comprehensive study on the flow characteristics in a combustor with seven swirl injectors. The analysis is based on a 3D large eddy simulation (LES) technique. The formulation consists of the Favre-filtered conservation equations of mass, momentum, and energy. The sub-grid scale dynamics are modeled by a compressible-flow version of the Smagorinsky model. The counter-swirl injectors (four-counterclockwise- and three-clockwise-swirl injectors) combustor and co-swirl injectors (seven-counterclockwise-swirl injectors) combustor were simulated to identify the effect of swirl direction The enormous effects on the flow dynamics are observed. In the co swirl injectors combustor, collision of swirl flow on the border of adjacent injectors reduced the central toroidal recirculation zone (CTRZ) of outer injectors, and expanded the CTRZ of central injector. In addition, strong rotational flow near the wall, formed by co swirl flow of outer injectors, deformed the swirl flows of six outer injectors. In the combustor with counter-swirl injectors, same direction of swirl flows on the border of adjacent injectors helped the swirl flow maintain along the axial direction. Furthermore, it increased the CTRZ of outer injectors but diminished the CTRZ of central injector.