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X3/R is a new large-scale free-piston-driven dual-mode shock expansion tube, developed and operated collaboratively by the University of Queensland (UQ) and Australia's Defence Science and Technology Group (DSTG). The facility can be converted between a long-duration reflected shock tunnel (RST), a super-orbital expansion tube (X-mode), and a non-reflected shock tube (NRST). In RST mode, the facility is currently capable of producing 600 mm diameter Mach 7 test flows at 25–50 kPa dynamic pressure for more than 10 ms. In expansion tube mode, the facility can reach enthalpies up to 80 MJ/kg for test times on the order of 500–1000 μ s. This paper presents the new facility, summarizes its current operational capabilities, and discusses key the technical challenges overcome during its development. [ABSTRACT FROM AUTHOR]

Reflected shock tunnels have been widely used for ground testing of hypersonic airbreathing engines. These facilities are able to replicate the total enthalpy and pressures experienced along hypersonic flight trajectories. Designing the relevant operating conditions is complex, and extensive guidance about operation condition design in reflected shock tunnels is scarce. To facilitate the operation of a reflected shock tunnel, it may be advantageous to develop a database of attainable conditions and the operation parameters required to achieve them. For this, a model to calculate global thermodynamic states and shock speeds also accounting for piston location and tube length (quasi-0D-model) is proposed. This model uses the NASA Chemical Equilibrium with Applications code to solve real gas and high-temperature effects. A number of conditions are calculated to produce maps of operating conditions. As test cases, the reflected shock tunnel under development at Tokai University, and T4 at the University of Queensland are used. Maps obtained sweeping rupture pressure or compression ratio, and initial test gas pressure for different driver compositions are presented. This methodology can be adapted to similar facilities. Moreover, observation of the presented maps provides a quick reference of the influence of each parameter when modifying existing conditions or fine-tuning tunnel operation. [ABSTRACT FROM AUTHOR]