3 m x 6 m icing wind tunnel

The 3 m x 6 m icing wind tunnel is a facility which bridges the gap between a conventional wind tunnel and an engine test cell. The wind tunnel has several unique features which lend themselves to a variety of applications.

The open-circuit layout, with fan at entry, permits contaminants associated with the test arrangements (such as heat, combustion products, wakes, jets, lost lubricants) to discharge directly, without re-circulating or contacting the fan. Additionally, a high solidity fan attenuates unsteadiness due to atmospheric wind. The fan is normally driven electrically but high-speed operation can be accommodated by a gas turbine drive system.

Working section velocity non-uniformities are generally less than 0.5 per cent of mean velocity and over most of the working section flow direction is within 1° of the longitudinal axis.

Experiments on models of aeronautical propulsion systems are facilitated by a connection to the NRC Aerospace compressor/exhauster facility. Compressed air to simulate jet effluxes or to drive turbine-powered fans, and suction to simulate intake characteristics, are available.

The wind tunnel is ideal for large-scale bluff-body aerodynamic investigations such as cable vibration studies. Inclined cables are prone to wind-induced vibration with amplitudes approximately equal to the cable diameter. This phenomenon is sensitive to Reynolds and Scruton numbers, which effectively means that full-scale cables must be tested at full-scale wind speeds. With the wind tunnel spray rigs, it is also possible to study rain-wind vibratory phenomena.

The length of the wind tunnel's test section also makes it ideal for simulating natural winds using the NRC-developed spire technique. Several recent investigations have focused on characterizing the highly turbulent air wake in the vicinity of aviation-capable ships.

Currently, the wind tunnel is being used in icing research. The open-circuit design of the wind tunnel means a naturally cold test section is available in the winter. This capability, combined with the working section height, results in the ability to simulate larger water droplets than most icing wind tunnels can support. Small cloud droplets have been simulated in the wind tunnel and the potential exists to do a freezing drizzle simulation. A test section insert is available to further increase wind speed.

Technical specifications

Tunnel geometry:

• Test section (w x h x l): 3.1 m x 6.1 m x 12.2 m (3.1 m x 4.9 m x 6.4 m with insert)
• Test section area: 18.9 m2 (15.2 m2 with insert)

Tunnel characteristics:

• Fan power:
• Electric = 750 kW
• Gas turbine = 6,000 kW
• 18.9 m2 test section max speed:
• Electric = 40 m/s
• Gas turbine = 54 m/s
• 15.2 m2 test section max speed:
• Electric = 50 m/s
• Gas turbine = 67 m/s
• Speed uniformity: ±0.5%

Auxiliary Systems:

• 480 port, computer-controlled icing-spray rig
• Compressed air: up to 14.5 kg/s at 700 kPa
• Flow traverse rigs: several, automated

Data system and instrumentation:

• Software: test specific MatLab & LabView
• Model mounts: pitch rig and custom mounts available
• Pressure measurements: Scanivalve ZOC™, Kulite
• Anemometry: hot-film/hot-wire
• Balances: internal (TASK, NRC, various) and external (cruciform, various)
• Photography: digital DVD, 35 mm
• Flow visualization: PIV, Acoustic Array, smoke, surface oil, fluorescent mini-tuft