Plume-Induced Missile Body Heating

There is a need for accurate predictions of threat TBM hardbody IR signatures, particularly in the development of plume-to-hardbody handover discrimination algorithms. However, current models for predicting missile body heating contained in the AerothermalTargets Analysis Program(ATAP) and the Optical Signatures Code(OSC) do not account for the influence of the exhaust plume of the missile, which can influence hardbody temperatures and IR signatures during both boost and mid-course phases of the trajectory.Accordingly, target IR signatures obtained via the use of ATAP/CHAMP or OSC can be underpredicted. The objective of this proposal is to describe an innovative program of work that will establish whether the magnitude of the plume-induced heating effectscan make a significant impact on hardbody IR signatures. The plume-induced heating effects to be accounted for in this program include: separation of the upstream boundary layer on the missile body, flameholding in the base/separated region and convectiveand radiant heat transfer from the plume to the missile base. Other potential contributors to missile body heating(not currently accounted for) include radiant heating from both internal surfaces(engine and nozzle) and external nozzle surfaces. Theseeffects will also be studied in this program. The principal benefits of the technology developed will be to those DoD components that require the use of ATAP/CHAMP and OSC for the accurate determination of hardbody IR signatures. Those agencies andprograms that would most likely make use of the new methodology include: MDA(BEST), AFRL,Eglin AFB(KHILS), DIA/MSIC(BMRD), NAIC(MASINT). Possible commercial applications include: enhanced capability to test sensor systems required to operate using passivetechniques and improved capability to determine base heating effects in the design of thermal protection systems for space launch vehicles.