Modern developments in hypersonic wind tunnels

Abstract

The development of new methods of producing hypersonic wind-tunnel flows at increasing velocities during the last few decades is reviewed with attention to airbreathing propulsion, hypervelocity aerodynamics and superorbital aerodynamics. The role of chemical reactions in these flows leads to use of a binary scaling simulation parameter, which can be related to the Reynolds number, and which demands that smaller wind tunnels require higher reservoir pressure levels for simulation of flight phenomena. The use of combustion heated vitiated wind tunnels for propulsive research is discussed, as well as the use of reflected shock tunnels for the same purpose. A flight experiment validating shock-tunnel results is described, and relevant developments in shock tunnel instrumentation are outlined. The use of shock tunnels for hypervelocity testing is reviewed, noting the role of driver gas contamination in determining test time, and presenting examples of air dissociation effects on model flows. Extending the hypervelocity testing range into the superorbital regime with useful test times is seen to be possible by use of expansion tube/tunnels with a free piston driver.

Development and commissioning of the T6 Stalker Tunnel

“…This driver was originally part of the T3 Shock Tunnel, which operated at the Australian National University from the late 1960s until the turn of the century. T3 used the first largescale free-piston driver, which proved the performance benefits and operability of the technology (Stalker 1966) and led to its adoption by several universities and national space agencies world wide (Stalker 2006). The availability of the T3 driver significantly reduced the capital cost of the freepiston design, therefore allowing the highest performance option to be chosen.…”

“…Reflected shock tunnels have been used extensively over the past half-century to study a range of high-enthalpy aerothermodynamic problems, including scramjet engine testing, boundary layer transition and hydrogen ionisation studiese.g. Stalker et al (2005);Stalker (2006). Physically, the difference between RST and SST modes is the presence of a converging-diverging nozzle at the downstream end of the facility, as shown in Fig.…”

“…Highenthalpy test facilities are therefore required to properly recreate the flight environment and to enable relevant data to be obtained. Stalker (2006) estimated that a continuous ground test facility capable of simulating re-entry conditions could require gigawatts of input power. This is evident in Fig.…”

Drag Reduction by Boundary-Layer Combustion: Effects of Flow Disturbances from Rectangular-to-Elliptical-Shape-Transition Inlets

“…All experiments were conducted in the T4 Stalker tube [27][28][29][30][31][32] at the University of Queensland. The test gases used for these experiments were air and nitrogen.…”

Development of a Fast-Response Diamond Calorimeter Heat Transfer Gauge

“…High enthalpy ground test facilities produce challenging environments in which to make surface heat flux measurements. Ultra-high speed pulse flow wind tunnels capable of producing total enthalpies equivalent to flight and matching binary scaling parameters have test times of the order 10 µs to 2 ms [1]. Instrumentation used must have sufficiently fast response times to produce useful data while also surviving both the extreme heat rates and impacts from fragments of metallic and plastic diaphragms that impact models at high speeds.…”