Thermo-mechanical fluid-structure interaction of reentry vehicle configurations in high-enthalpy flow fields

Kurzfassung

Thermal protection systems (TPS) and hot structures play a key role for the efficiency and safety of future reusable space transportation systems (STS). The thermo-mechanical behaviour of highly loaded components, such as nosecaps and control surfaces, in chemically reacting high-enthalpy flow fields can only be predicted with large restraints. E.g. heat loads are usually estimated from the fluid analysis without taking into account any heat conduction into the structure. These restraints, in addition to a lack of reliable data from flight test and experiment, lead to high safety margins, which increase the mass and therefore the costs of future reentry vehicles. To obtain a more accurate prediction of the thermal loads and the structural response during the reentry flight, one of the primary objectives of the DLR project IMENS (Integrated Multi-disciplinary dEsigN of hot Structures) has been the development of a software environment which enables one to perform a coupled numerical analysis of fluid and structure. Before such coupled simulations become common design tools for future STS, however, it is necessary to validate their numerical results with well-suited experimental data. Therefore, a generic model of a reentry vehicle body-flap section was designed and tested in DLR's arc-heated facility L3K to build up an experimental database for the validation of coupled numerical simulations. Fluid-structure simulations were performed using a Navier-Stokes code for the calculation of the hypersonic flow field and a finite-element solver for the thermal analysis of the structure. The data transfer between the grids was carried out via an interpolation routine. By comparing the numerical results from coupled simulations, as well as from stand-alone CFD-analysis, to the experimental data, it was shown that the coupled approach can contribute well to a reliable design of TPS and hot structures of reentry vehicles.