Aerothermal analysis of an advanced hot structure for hypersonic flight tests
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Aerothermal analysis of an advanced hot structure for hypersonic flight tests Raffaele Savino1, Mario De Stefano Fumo1, Giuliano Marino2, Mario Tului3 1 Dept. of Space Science and Engineering (DISIS), University of Naples (Italy) 2 Centro Italiano Ricerche Aerospaziali (CIRA), Capua (Italy) 3 Centro Sviluppo Materiali (CSM), Roma (Italy) ABSTRACT This paper deals with the aerothemodynamic analysis of an advanced concept of hot structure to be investigated in the Expert flight test programme. Three-dimensional fluid dynamic computations have been carried out at the flight conditions of the reference Expert trajectory to evaluate the aerothermodynamic field and the thermal loads on the winglet. The physical model includes viscous effects, real gas properties, non equilibrium chemical reactions and surface catalytic effects. The unsteady aerothermal analysis has been carried out considering different thermal boundary conditions (adiabatic wall or thermal coupling with the capsule metallic skin). The results are discussed with particular attention to the temperature distributions in the Ultra High Temperature Ceramics (UHTC) and in the structural support. INTRODUCTION The European Space Agency (ESA) is pursuing the Expert hypersonic flight test programme to give unique opportunities to improve knowledge of challenging problems of hypersonic flight[1]. The configuration chosen for the Expert vehicle is basically a “blunt cone” with four flaps and flat surfaces ahead of them. The vehicle will take advantage of the Russian Volna launcher capabilities to make controlled ballistic suborbital flights to study the most critical aerothermodynamic phenomena and then to be recovered for post flight inspection[2,3]. Among other scientific payloads, the vehicle will carry an advanced concept of hot structure based on the development of ultra high temperature ceramics (UHTC)[4]. In particular two winglets will be placed at the base of the capsule(Fig.1) in a diametrically opposite positions, preserving the symmetry of the re-entry capsule. Specific goals of this payload are: 1) to test UHTC (e.g. ZrB2/SiC and/or HfB2/SiC and/or ZrB2/SiC/C) for future spacecrafts at hypersonic re-entry conditions (total enthalpy > 10 MJ/Kg, stagnation point heat flux > 5 MW/m2, surface temperature > 2000 °C); 2) to assess potential advantages related to the relatively high emissivity and high thermal conductivity that make UHTCs particularly well suited for use as massive leading edges of sharp fuselages and wings (boundary layer thermal protection)[5]; 3) to investigate the behaviour of UHTCs at overall radiative equilibrium conditions (radiative cooling); 4) to investigate surface catalytic properties of UHTCs with respect to recombination reaction in presence of a highly dissociated oxygen mixture (through comparisons with Plasma Wind Tunnel results and between calculated and measured heat transfer rates); 5) to compare flight results with Plasma Wind Tunnel (PWT)
Mater. Res. Soc. Symp. Proc. Vol. 851 © 2005 Materials Research Society
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