Enhanced Scramjet Combustion

Period of Performance: 12/09/1999 - 11/27/2000

$120K

Phase 1 SBIR

Recipient Firm

Combustion Research & Flow Technology
6210 Keller's Church Road Array
Pipersville, PA 18947
Principal Investigator

Research Topics

Abstract

A state-of-the-art Computational Fluid Dynamic/Large Eddy Simulation (CFD/LES) methodology that has well established aero-acoustic capabilities will be implemented for investigating flow induced oscillations of cavity flowfields and a theoretical understanding of cavity acoustic suppression via leading edge jet blowing will be developed. Numerical investigations will be conducted using the three-dimensional, finite volume CFD code, CRAFT, which utilizes a fully implicit, characteristic based upwind scheme with higher order spatial and temporal accuracy to provide for accurate shock capturing while simultaneously preserving acoustic accuracy. Prior applications of CRAFT (in conjunction with LES) to various cavity/ducted problems have demonstrated its ability in providing accurate representation of unsteady flowfields characterized by pressure oscillations, periodic vortex shedding, acoustic feedback and instability modes. The ability of open-loop leading edge jet blowing to provide suppression of acoustic loads in a cavity will be systematically investigated and optimization of leading edge jet blowing will be conducted. Varied spectral analysis techniques will be employed to identify acoustic source location. The proposed research also provides the foundation for evaluation of cavity suppression via closed-loop leading edge jet blowing. BENEFITS: The proposed research is directly relevant to design of acoustic suppression techniques for future combat aircraft (F-22, JSF, etc.) and UCAV which feature internal bays. The research also supports development of novel technologies for abatement of jet engine and industrial equipment noise. Within the energy sector, cavity analysis technique finds application in the design of boilers, furnaces, incinerators, etc. where combustion instability is a major concern.