Use of Argon-Helium Driver-Gas Mixtures in the T4 Shock Tunnel

Helium-argon mixtures have been used as the driver gas in the T4 shock tunnel for moderate enthalpy conditions between 3 MJ/kg and 15 MJ/kg. The experimental data showed that constant conditions could be maintained in the shock-reflection/ nozzle-supply region for significantly longer times than for a pure helium driver. Results from quasi-one-dimensional simulations of the facility agreed with the experimental data and provided further detailed information on the performance of the facility.