Metadata
Title
Oxford Thermofluids Institute
Category
undergraduate
UUID
39b8cacb7bbc4f558f93472962169569
Source URL
https://oti.eng.ox.ac.uk/facilities/hypersonic-facilities
Parent URL
https://oti.eng.ox.ac.uk/
Crawl Time
2026-03-09T03:23:16+00:00
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Oxford Thermofluids Institute

Source: https://oti.eng.ox.ac.uk/facilities/hypersonic-facilities Parent: https://oti.eng.ox.ac.uk/

The group has three world-class, high-speed wind tunnels, capable of producing flow from supersonic to hypersonic and all the way to hypervelocity:
Facility Mode Mach P0 [MPa] T0 [K] Test time [ms]
T6 Stalker Tunnel Multi-mode Facility 6-30 75/1000’s 5000/10,000’s 0.05-2
High Density Tunnel Ludwieg / LICH 3-10 25 1250 70-500
Low Density Tunnel Suck down 6-10 0.01 273 continuous

The facilities are part of the National Wind Tunnel Facility. This offers a minimum of 25% access of the tunnels and instrumentation to outside parties (academic or commercial).

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Hypersonics Facility

Hypersonics Facility

A 360 view of our Hypersonic T6 and HDT tunnels.

T6 Stalker Tunnel

Schematic of the T6 Stalker Tunnel in Reflected Shock tunnel mode

T6 Stalker Tunnel

The T6 Stalker Tunnel (T6) is Europe’s highest speed wind tunnel, capable of producing flows in excess of 20 km/s. It is a multi-mode facility, capable of operation either as reflected shock tunnel, an expansion tunnel or a shock tube. The facility is driven by the T3 free piston driver, designed by the late Prof. Ray Stalker, being one of the most powerful created in the world. The facility was developed by the University of Oxford (McGilvray and Doherty) in collaboration with the University of Queensland (Morgan and Gildfind).

T6 Stalker Tunnel specifications in different modes of operation:
Facility Reflected Shock Tunnel Expansion Tunnel Shock Tube
Testing type Subscale model Subscale model Shock layer radiation
Test duration 1-3 ms 50-500 μs 2-50 μs
Flow core diameter 150-200 mm 50-120 mm 80 or 250 mm
Max flow speed 6.5 km/s 12 km/s 18 or 9 km/s

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High Density Tunnel

Schematic of the High Density Tunnel (HDT)

High Density Tunnel

The High Density Tunnel (HDT) is a reconfigured and upgraded facility from the original RAE shock tube, acquired by the University of Oxford in 2012. It operates either as a Ludwieg tunnel or a Light Piston Compression Heating facility, producing cold hypersonic flow conditions with test times long enough to investigate unsteady flow effects.

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Low Density Tunnel

Low Density Tunnel

The Oxford Low Density Tunnel (LDT) is a hypersonic rarefied flow facility that has been in operation at the University of Oxford’s Department of Engineering Science since 1963. This wind tunnel operates as a free-jet, open-circuit, continuous-flow facility that produces hypersonic test flows primarily in the slip and transition regimes.

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The test gas may be any inert gas and total temperatures up to ~550 K are currently possible, though there are plans to extend this to >1000 K. Acceleration of the test gas from the stagnation chamber is by way of a contoured Mach 6 nozzle, although conical nozzles and orifice plates have been used in the past to achieve free-molecular flow conditions [1, 2]. The current Mach 6 nozzle has an exit diameter of 108 mm and produces a core flow region of 40 mm diameter, depending on the test condition. Other Mach number nozzles may be developed in the range 4 to 12.

The test section consists of a large cylindrical vessel approximately 1540mm in diameter and 1500mm length with the axis perpendicular to the nozzle axis. Access to the test section may be from either side through full-size dished doors allowing for the installation of experimental kit.

The pumping system at the core of the facility is one of approximately four identical systems produced by Edwards Vacuum at the time of manufacture (early 1960s). It consists of an Edwards 100B4 ejector vapour booster pump backed by an 1R80 Roots-style mechanical booster pump and three HISC3000 rotary piston pumps. As a whole, the system is capable of pumping 22 000 l/s at back pressures up to ~2 Pa. With no gas admittance, the system is capable of achieving an ultimate pressure of ~0.01 Pa. The facility has been refurbished and recommissioned over the period 2014 – 2018, further details of which may be found in Donaldson et al. [3].

The Oxford Low Density Tunnel is suitable for experimentally investigating aero-thermal phenomena at high altitudes (approx. 70 – 90 km) such as control jets, multi-body interactions including shock-shock and shock-boundary layer interactions. It is well suited for characterising the heat transfer to satellites or debris during re-entry.

Experimental techniques currently employed include heat transfer measurements using liquid crystals, infrared thermography or thin-film heat transfer gauges and aerodynamic force measurements using a load-cell. A multi-axis traverse system is employed and an existing 3-component magnectic suspension balance system is to be recommissioned to enable precise force measurement and sting-free model attitude control.

Previously the LDT has been used to investigate:

  1. the heat transfer distribution on satellite anologue geometries (flat faced cylinders, hemisphere cylinders, etc)
  2. the effect of wall-to-temperature ratio on the drag of spheres and cones across the range of contimuum to free-molecular flow
  3. the variation in lift and drag of cones at angle-of-attack with Knudsen number
  4. wake flows behind vehicle analogue geometries
  5. comparisons between DSMC simulations and experimental drag measurements for cones and Aerobrake geometries

References

[1]           Haslam-Jones, T. F., “Measurements of the Drag of Slender Cones in Hypersonic Flow at Low Reynolds Numbers using a Magnetic Suspension and Balance,” DPhil thesis, University of Oxford, Department of Engineering Science, Oxford, UK, 1977. Also Dept. of Eng. Sci. Report 1235/78 (1978).

[2]           Hadjimichalis, M., “A Study of Sphere Drag in the Transition from Continuum to Free Molecular Flow,” DPhil thesis, University of Oxford, Department of Engineering Science, Oxford, UK, Oct. 1973. Also Dept. of Eng. Sci. Report 1073/73 (1973).

[3]           Donaldson, N., Doherty, L. J., Ivison, W., Wilson, C. F., McGilvray, M., and Ireland, P. T., “Refurbishment and Characterisation of the Oxford Low Density Hypersonic Wind Tunnel,” International Conference on Flight Vehicles Aerothermodynamics and Re-entry Mission & Engineering (FAR), ESA, Manopoli, Italy, 2019.

Osney Plasma Generator (OPG) plasma facility

OPG is a miniaturised plasma wind tunnel based on a thermal arc-jet plasma generator. The facility can provide continuous high-temperature plasma flows creating high heat fluxes representative of loads experienced during hypersonic flight. Two plasma generators are available (OPG1 and OPG2) which allow the testing of Argon, Nitrogen, and synthetic Air test gases. Material samples can be placed on a linear traverse system to position them in the plasma flow. The facility has been commissioned in 2023.

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Cold-driven Expansion Tube CXT

CXT is a cold-driven expansion tube designed to produce flow velocities between 2 km/s and 6 km/s. The facility is approximately 12 m long and consists of a Helium driver (up to 80 bar), a shock tube , and acceleration tube of approximately 180 mm diameter. The facility utilises previous infrastructure of the T6 Stalker tunnel and the MCF Ludwieg Tube. A key feature is the operation of CXT in a hybrid mode which utilises the OPG plasma source to pre-heat models before exposure to a hypervelocity flow. The facility is currently in its commissioning phase.

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