Time Resolved Particle Image Velocimetry Measurements of Non-Isothermal Vortex Breakdown Onset

Vortex breakdown occurs in many flow applications and controlling breakdown onset is often desirable. While there is an abundance of research into the behavior of vortex breakdown, there is limited understanding of the mechanisms that drive this process and the end state, especially in non isothermal flows. Previous research has motivated this work by suggesting that blue fire whirls could be controlled through heat addition at the breakdown bubble. The current work aims to experimentally show the effects of heating on the onset and structure of vortex breakdown in an incompressible non-reacting vortex flow. A new vortex breakdown rig has been developed to allow for high-speed particle image velocimetry and heating at the recirculation bubble. Time-resolved flow field measurements of the breakdown flow structures were taken with varying levels of heat addition, focusing on the process and onset of breakdown. The effects of the added heat on the breakdown characteristics were evaluated and compared to computational results. The results shed light on the experimental viability of controlling vortex breakdown via heat addition.