Swirl Generation and Recirculation Using Radial Swirl Vanes

The concept of the Swirl Number and its effect on recirculation is reviewed and problems with it are identified. Swirl generation through the use of radial inlet swirl vanes is then studied. The effect of vane and swirl cup design on recirculation is then evaluated using finite element computer modeling and verified using tufting tests. Vane geometry, combustor dome geometry, co- vs. counter-rotation and mass flow effects are all evaluated. It is shown that co- and counter-rotation generate very similar flow fields and recirculated mass flows. An approach for calculating swirl numbers in multiple swirler designs is proposed.