Title

Numerical Study of Energy Utilization in Nozzle/Plume Flow-Fields of High-Speed Airbreathing Vehicles

Abstract

Focused local energy deposition in both internal and external flow-fields associated with high-speed aerospace vehicles can provide many system level benefits. This study specifically analyzes the effects of targeted (local) energization of the flow in the nozzle and afterbody flow-field regions of a sub-scale hypersonic lifting body configuration. Benefits are shown to include the generation of a favorable vehicle pitching moment (nose-down) increment associated with such energy deposition and a reduced local and overall thermal load in both combustor and nozzle for all cases examined. These results have been obtained by modeling the nozzle/afterbody region of a simple generic 2-D waverider/ lifting body utilizing computational fluid dynamics (CFD). In these simulations energy was deposited locally in the flow-field; energy location, amount, and the shape and extent of the energized zone were then parametrically varied Force distributions were then integrated to obtain overall axial force contributions and moment effects on the vehicle surfaces modeled; these are compared to the baseline (i.e. the configuration with no nozzle/afterbody energization). The distribution of the temperature on the adiabatic nozzle/afterbody wall surface (which serves as an indicator of thermal load effects on the vehicle) is also examined. It is shown that by optimal placement of a single intense energy deposition, increases in the overall engine nose-down moment of 50-125% and reductions of up to 500 K in the wall temperature distribution throughout the nozzle/afterbody region of the engine can be achieved. There are penalties in the overall engine thrust (axial force) production of 15-20% when energy is added other than in the combustor (due to the inevitable reduction in thermal efficiency), however it is conjectured based on the results of this preliminary study that the overall system benefits (favorable moment effects and reduced heating loads) may to some degree outweigh these propulsive penalties in order to allow for optimization of the entire vehicle.

Meeting Name

ICAS Secretariat - 26th Congress of International Council of the Aeronautical Sciences 2008

Department(s)

Mechanical and Aerospace Engineering

Keywords and Phrases

Aircraft Design; Hypersonics; Propulsion

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 International Council of the Aeronautical Sciences, All rights reserved.

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