The Effect of Bluff Body Flameholders on the Inter-Turbine Burner Performance

In this thesis, a three-dimensional numerical simulation has been conducted to study the complex reactive flows which are present during the combustion in an inter-turbine burner (ITB) with the inclusion of V-gutter flame holders. Optimal conditions for the V-gutter were then further studied through a parametric study. The ITB configuration with straight radial vanes (SRV) was based on the innovative, high efficiency, high-g Ultra-Compact Combustor (UCC) concepts developed at the Air Force Research Laboratory (AFRL).

For the first section, the V-gutter’s angle of attack was varied from -10 degrees to 10 degrees. The turbulent flow was modeled with a RANS-based realizable k-epsilon turbulence model, while the Jet-A spray combustion is modeled with the eddy-dissipation model. Numerical results indicate that the V-gutter not only generated vortices behind itself, but also altered the turbulent flow features and mixing behavior between main air flow and the circumferential and SRV cavity flows within the ITB. The exit temperature profile of the ITB could be modified substantially by the inclusion of the V-gutters at different angle of attack. The additional pressure drop incurred by the addition of the V-gutter was found to be less that 1 percent. Details of the vane cavity dynamics and increased entrainment physics were also discussed in the paper.

In the second section, a numerical parametric study has been conducted to examine the effects of varying both inlet turbulent intensity and angle of attack for a bluff body flame holder (V-gutter) in a cavity. The geometry used was based on previous experimental work. The inlet turbulent intensity was varied from 2 percent to 100 percent while the angle of attack of the V-gutter was varied from 0 degrees to 30 degrees. The combustion setup used was premixed propane-air combustion with an equivalence ratio of 0.6. The same numerical models which were used in the first section were also used here. Results indicated that increasing the inlet turbulent intensity and V-gutter angle of attack resulted in an increase not only in the size but also in magnitude of the downstream high turbulence areas with vortexes.