Scramjet Combustor Modeling

An advanced computational framework for scramjet combustor simulation will be developed via turbulence extensions to a finite-volume implicit/upwind Navier-Stokes code that presently contains generalized multiphase combustive capabilities and is operational on parallel architecture machines using domain-decomposition with MPI protocol. Turbulence upgrades will include: use of nonlinear (explicit algebraic Reynolds-stress) extensions to two-equation turbulence models such as ke; nonequilibrium compressibility extensions; variable turbulent Prandtl number modeling; and, an assumed PDF approach for turbulent chemistry. A unique feature of this framework will be the ability to use different turbulence modeling procedures in different zones, recognizing the limited invariance of even the most sophisticated turbulence models and the need to cater such models' varied dominant features. Phase I work will be limited to gas-phase combustion while Phase II will emphasize multiphase combustion aspects as associated with solid propellant gas generator partially burnt products and varied new fuels (gel-based, fullerenes, etc.). Analyses of relevant scramjet experiments utilizing swept ramp injection concepts to enhance mixing with minimal performance loss will serve to validate the advanced turbulence modeling framework. BENEFITS: This work not only benefits scramjet and related airbreathing propulsive technology, but also enhances our ability to analyze other missile components such as lateral jet thruster interactions and base combustion, critical for TMD interceptor design and signature applications. Support to improve noise reduction in commercial airplane turbofan exhausts (via turbulence upgrades) and overall performance enhancements in internal combustion engines (via turbulent-chemistry methodology ) result from this work.