Design of a Hot Wall Wind Tunnel Model for Investigation of the Shock-Wave / Boundary-Layer Interaction in the High Enthalpy Shock Tunnel Göttingen (HEG)

Abstract

A hot wind tunnel model with a wall temperature of 730K was designed in this work. The model will be used to investigate the shock-wave / boundary-layer interaction and the transition depending on the wall temperature in the High Enthalpy Shock Tunnel Göttingen (HEG). An extensive investigation of previous work with heated wind tunnel models was made and the applied heating techniques were discussed and evaluated. After a rst concept study the SWBLI wind tunnel model was designed. The required heating power to achieve the desired wall temperature was estimated by means of analytical methods. Numerical thermal analysis were made by means of Finite Element Methods (FEM). Two computation tools were programmed for oblique shocks and Prandtl-Meyer expansions to calculate the pressure distribution around the model. Furthermore, numerical mechanical stress analysis to account for the aerodynamic loads were conducted. In this context an own approximation formula was developed for oblique shocks at a 2D de ection respectively around a wedge, which could calculated easily by a hand calculator. In the scope of the design process, the heating technique, the instrumentation, the materials, the control circuit, the thermal compound and the high temperature glue were evaluated and dened. A generic model was designed, machined and investigated in the vacuum chamber to evaluate the design. The functionality of the heating technique, the chosen materials and the heating control circuit were tested. The preliminary tests on the generic model revealed several unexpected problems which are discussed and considered in the nal wind tunnel model design. Finally, the experimental results were compared with numerical results of the test plate. The comparison conrmed the design of the wind tunnel model by means of FEM.