Design of the University of Tennessee High-Enthalpy Tunnel

View Video Presentation: https://doi.org/10.2514/6.2021-0382.vid This paper discusses the design of the University of Tennessee High-Enthalpy Tunnel (Tenn-HET), a general purpose hypersonic facility that will be used for fundamental research in aerothermodynamics and high-speed flows. The high-enthalpy flow is provided by an arcjet-type gas heater with a nominal power of 260 kW in continuous mode and 500 kW in pulsed mode. Pulsed mode allows test times up to 500 ms at significantly reduced cost compared to a continuous flow tunnel with the same nominal power. The first part of the paper provides an overview of the main components and the functioning of the facility, with particular emphasis on the tunnel startup phase, i.e. ignition and stabilization of the electric arc. The second part is focused on the design of the constricted arc-heater. A theoretical model and related computational procedure for the simulation of a plasma flow in a constrictor channel are presented. Numerical simulations are used for the optimization of the constrictor geometry and the prediction of the arc-heater performance. The study revealed that a dual anode configuration is necessary to maximize the operating range of the tunnel. A shorter arc length (50 mm) is used to reach stagnation conditions at high pressure (>1 MPa) and low enthalpy(<5 MJ/kg), whereas a longer arc (80 mm) is used for lower pressures (<0.5 MPa) and higher enthalpies (>10 MJ/kg).