Influence of incoming flow parameters on the flow field in a trapped vortex cavity with radial bluff-body

Abstract

The study focuses on a novel trapped vortex pilot flameholder (TVPF) design, which combines a pilot cavity that has individual air inlets, with a V-shaped radial bluff body. The flow field under sub-atmospheric pressure was investigated using particle image velocimetry (PIV) systems, obtaining the velocity distribution, vortex position, and vorticity distribution for different inlet parameters. Corresponding analysis revealed the overall flow structure of the cavity-flameholder combination, together with the different flow fields under various positions, total pressure, and inlet Mach number. The results show that from the central plane towards the side of the cavity, a no/single vortex to double vortex structure is observed inside the cavity. The three typical flow patterns are radial flameholder entrainment dominated, transition state and high-speed mainstream dominated, each has different velocity distribution and vortex structure. High vorticity mainly exists on both sides of the inlet air and the shear layer between the cavity and mainstream. The alteration of inlet parameters will lead to the change in the cavity jet's momentum, affect the self-sustaining capacity of the cavity vortex system under the influence of mainstream flow, and further lead to different changes in the flow field under the three flow patterns.