Cold Wind Tunnel CWT-1
The CWT-1 facility is a low speed, closed circuit wind tunnel capable of operating at subfreezing temperatures. Built out of wood and epoxy-fiberglass composite, it is internally insulated with a 5 cm layer of polystyrene foam covered by a smooth epoxy lining. The settling chamber, fitted with a honeycomb, is followed by a 12.4 to 1 contraction and a 1.6 m long test section with 0.1 m x 0.3 m cross section. The top and bottom walls of the test section are made with double glazing to provide optical access. The centrifugal fan is driven by a PC-controlled variable-speed 8 kW DC motor to achieve any specific speed-time history. Maximum flow velocity of 70 m/s can be reached in a controllable time (10 seconds minimum) after starting the tunnel. Cooling of the facility is achieved by injection of pressurized liquid nitrogen through spray nozzles located in the return circuit, which is typical for cryogenic tunnels.
This facility was specially designed to study the motion of films of anti-icing fluids applied to aircraft wings during a simulated take-off. It was used to define the international standards for certification of aerodynamic acceptance of aircraft de/anti-icing fluids, and is also suitable for optical measurements of surface wave motion, and for general flow studies or instrument calibration at temperatures as low as -40ºC.
The CWT-1 Facility can also be run at room temperature in an open circuit configuration with other test sections, one specifically designed for measurements of liquid-air interface instabilities, and another for the study of perspiration heating on porous wing panels for deicing purposes.