Suitability of Non-Reactive Flow Simulations in the Investigation of Mixing and Flameholding Capability of Supersonic Combustor Flameholder

ABSTRACT

A comparative study is performed to investigate the effectiveness of non-reactive supersonic flow simulations in qualitatively predicting the mixing performance and flameholding capability of a pylon-cavity aided, sonic ${\mathrm{H}}_2$ fuel injection flameholder under, reactive flow conditions. The performance parameters such as mixing and combustion efficiencies, and flammable plume area are taken into account for the study. A non-reactive, steady-state RANS simulation is solved using coupled, implicit, second-order upwind solver with a two-equation SST κ-ω turbulence model. The numerical scheme is validated experimentally using steady wall pressure data and 2-D velocity vector field. Similar steady-state modeling has been performed for a reactive flow simulation with an 18 step Jachimowski reaction scheme for ${\mathrm{H}}_2$-air reactants. The study consists of two distinct injection locations on the cavity floor. Inlet Mach number of 2.2 is maintained for all the cases. The study shows that the cavity vortex pair with recirculating hot burned gases plays a decisive role in accurately predicting the flame location within the configuration. Though the non-reactive flow simulations are helpful in understanding the fundamental mechanisms also relevant under reactive flow conditions, like fuel-air mixing for example, it fails in the accurate prediction of the ignition location and flame stabilization.

KEYWORDS:

• Scramjet
• reactive and non-reactive flows
• mixing performance
• PIV
• CFD

Acknowledgments

The authors would like to express their thanks to Dr. Aravind Vaidyanathan and Prakash RS. for assistance in conducting the experiments.