Integrated Analysis of Reusable Thermal Protection Systems Based on Variable-Transpiration Cooling


Reusable thermal protection systems are one of the key technologies that have to be improved to use hypersonic vehicles as practical, long-range, transportation systems. The proposed concept of variable-transpiration cooling is investigated in this work by coupling the hypersonic boundary-layer solution with the thermal response of a porous material. The simulations of the hypersonic boundary layers are obtained using an in-house-developed reduced-order model capable of handling generic injection velocity profiles at the porous wall and the high-fidelity computational-fluid-dynamics code Langley Aerothermodynamic Upwind Relaxation Algorithm. The material thermal response is included adopting a one-dimensional model for the porous medium. The integrated analysis is performed for a flat plate and a two-dimensional blunt-body configuration. A sawtooth wall velocity profile was chosen to represent the variable-transpiration strategy. The uniform transpiration on the blunt body allows for a reduction of the stagnation point heat flux by 48% in comparison with the case without transpiration. The variable transpiration reduces the stagnation point heat flux by an additional 8%. The integrated analysis highlights the coolant blockage effects, the potential offered by the variable-transpiration cooling, and the necessity of performing a coupled flow-material analysis, at the design stage, to define realizable combinations of porosity, thermal conductivity, and material thickness capable to guarantee the thermostructural integrity of the thermal protection system.


Mechanical and Aerospace Engineering

Research Center/Lab(s)

Center for High Performance Computing Research

Keywords and Phrases

Algorithms; Computer Simulation; Cooling; Heat Flux; Heat Shielding; Heating; Hypersonic Flow; Hypersonic Vehicles; Porous Materials; Thermal Insulating Materials; Transpiration; Boundary-Layer Solution; Integrated Analysis; One-Dimensional Model; Reduced Order Models; Relaxation Algorithm; Stagnation Point Heat Fluxes; Thermal Protection System; Transportation System; Thermal Conductivity

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 2014 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

01 Jan 2014