Stability Models for Augmentor Design Tools and Technology Assessment

We are proposing a joint experimental/modeling and computational study to develop stability models for CFD codes to design advanced augmentors. Experiments will be conducted at the Research Institution to address various issues related to augmentor stability under vitiated conditions. A stream of vitiated air will be established within an existing vertical wind tunnel. Fuel jets in crossflow and bluff body stabilized jets will be placed into this stream. Available state-of-the-art measurement instruments and visualization techniques will enable us to study the role of vitiation and bluff body shedding upon the jet mixing, flame stabilization, and the downstream jet development. Moreover the effects of changes in altitude will be imitated and studied by varying the jet to momentum crossflow ratio. At our firm, a highly sophisticated, fully unstructured, multi-physics LES code for compressible turbulent combustion already exists. A newly developed auto-ignition model will first be extended for vitiated combustion conditions, and then validated against Cabra et al.'s detailed experiments of reactive flows in vitiated environments. Next, LES simulations of augmentor type geometries will be performed and validated against data from the Research Institution. Using experimental and simulation results, reduced stability models and novel flame holding concepts will be suggested and evaluated.