Propulsion Related Missile Phenomena

Our proposal addresses the high fidelity simulation of dynamic, post-burnout propulsive related events whose radiative characteristics are observable by space-based optical sensors. Events include persistent trails, fuel venting, tank rupture, etc. Wewill utilize a very advanced compressible gas/liquid CFD code that already contains much of the requisite physics and thermo-chemistry (atomization, vaporization, etc.) in a dynamic grid framework that has been developed to analyze the extended plume(launch to target) for tactical scenarios, and has also been used to analyze post-hit liquid flyout/breakup events. For Phase I, we will focus on fuel venting events and start with a simplified scenario where fuel vents from the rear of the missile intothe wake. Simulations will require a detailed portrayal of the missile wake structure (base can serve as flameholder, neck region can produce shock-induced ignition) and use of nonequilibrium droplet vaporization/combustion modeling. We will performtime-accurate calculations at 20, 40, and 60 km to scope-out the overall features of the vented fuel problem and then analyze a case for which radiometric data is available. Rectification with data will include examining sensitivities to the atomizationand combustion models as well as seeking out complexities not addressed. There is significant commercial potential for this work. The most obvious is the need for such a broad-based model by the missile defense community to support variedobservable/communication activities where our role in supporting varied primes and programs such as BEST can greatly expand. Less obvious, is the use of this multi-phase methodology for applications such as thermal spray coatings where molten metallicdroplets are injected into a high temperature surrounding air stream very much akin to the Phase I fuel venting work. Lastly, we are involved in developing hybrid chevron concepts for jet noise reduction on aircraft where we are using innovativedroplet/vaporization concepts that can be enhanced by the technology development in this program.