ISBN 9783843921114

978-3-8439-2111-4, Reihe Ingenieurwissenschaften

Sarah Frauholz
Advanced Numerical Investigations of Hypersonic Scramjet Intake Flows

175 Seiten, Dissertation Rheinisch-Westfälische Technische Hochschule Aachen (2015), Softcover, A5

Zusammenfassung / Abstract

The aim of this work is to improve the accuracy of numerical computations of scramjet intake flows in order to achieve a deeper physical knowledge about scramjet engines. Three different scramjet intakes are analysed using a well-validated in-house finite volume flow solver. This work is conducted in a close cooperation to experimental campaigns and provides numerical data that support the preparation and the interpretation of ground-based measurements. In order to perform 3D high-fidelity computations at affordable computational cost, the multiresolution-based grid adaptation implemented within the applied in-house flow solver is validated and verified for highly grid-sensitive hypersonic flows. Afterwards the focus of this work rests on three selected physical topics that are crucial in the context of scramjet intake flows, i.e., the laminar-to-turbulent transition, the extrapolation from windtunnel conditions to flight conditions and the thermal state of the scramjet engine walls. In this context, the modelling of the laminar-to-turbulent transition is strongly improved by the newly implemented RSM-Tr model. After showing a very good overall agreement of numerical computations for the three scramjet intakes to available experimental measurements, the intakes are analysed at flight conditions with respect to the intake performance and the supersonic combustion. Here the effect of aerothermal heating of the engine walls is addressed by increasing the isothermal wall temperature up to 800 K and by coupled aerothermal computations allowing a physical non-homogeneous temperature at the fuid-structure interface. The numerical investigations of the three intakes proved a very good performance at flight conditions allowing stable self-ignition of the fuel with respect to the chosen injection systems.