THERMAL-STRUCTURAL ANALYSIS OF THE DARPA HYCAUSE 3-D ENGINE FOR FLIGHT TEST

[Abstract] This paper describes the results of a non-linear transient thermal-structural analysis of the DARPA HyCause Mach 10 scramjet engine. The thermal-structural response of the engine was studied for the descent trajectory from 60 to 37 km, as part of the design strategy. Aerodynamic and combustion heating fluxes, which varied with spatial position and altitude, from CFD analysis ‡ and shock tunnel experiments § were incorporated into the 3-D thermal-structural finite element models to assess the temperature distribution, engine geometry distortion and yielding of the structural material due to aerodynamic heating during the descent trajectory. High temperature constitutive models were developed, using the temperature dependent material properties measured in our earlier study, for implementation in the FE thermal-structural analysis. This analysis provides a unique and relatively simple structural design strategy for predicting and mitigating the aero-thermalstructural response of the vehicle. It has enabled the selection of appropriate materials and optimisation of the wall thickness of the combustor, isolator and intake.