Preliminary development of high enthalpy conditions for the X3 expansion tube

The University of Queensland (UQ) operates two free piston [1] driven expansion tubes - X2, and the larger X3 - for conducting simulations of atmospheric entry. Recently, high enthalpy experiments have only been performed in X2 but there is interest to develop the capability for high enthalpy experimentation in X3 as it’s size allows for experimentation with larger scale models. To achieve these conditions, a new light weight piston and reservoir extension have been commissioned. This paper presents a preliminary investigation into the development of new operating conditions for X3 using the recent upgrades

Tomographic optical emission spectroscopy of a high enthalpy air plasma flow

A method is presented allowing for locally resolved emission spectroscopy using a tomographic setup. The approach presented in this work is applied to a high enthalpy air plasma flow. The resulting data sets allow for a three-dimensional (3D) representation of the non-symmetric flow field using photographs of the test section and 2D representation of the spectrally resolved radiance of the flow field. An analysis of different exposure times shows that transient fluctuations of the plasma can result in substantial asymmetry that approaches symmetry only for longer exposure times when the temporal averaging of the emission is significant. The spectral data allows the analysis of species selective excitation and emission. A non-equilibrium between atomic and molecular excitation temperatures is concluded for the investigated air plasma flow field. The spatial distribution of atomic electronic excitation temperatures are close to rotational symmetry while molecular rotational and vibrational temperatures exhibit asymmetric behavior

Commissioning of the T6 Stalker Tunnel

First commissioning results are presented from the new T6 tunnel — a multi-mode pulse facility for high-enthalpy hypersonic research at the University of Oxford. A brief summary of the history of these facilities and a description of the current arrangement is provided. Re-commissioning tests of the modified T3 free piston driver section are then presented, for which it was found that a single set of model parameters could adequately match experimental data for all conditions. Preliminary results of wall pressure and heat flux measurements from the commissioning shots in shock tube mode are then given and comparisons made to numerical predictions of facility performance. Finally, results from a Pitot rake mounted in the test section are presented and discussed