The RC-1 facility allows performing aero-thermal evaluations in rotation of flows characterized by low Reynolds number, strong Coriolis forces, considerable heat transfer and wall roughness. Typical examples of such flows are found in Micro Gas Turbine centrifugal compressor impellers or High Pressure Turbine internal cooling channels. The centrifugal impeller passages or the internal cooling ducts are scaled and reproduced by Plexiglas channels.
The test section length can be as high as 1 m, with an inlet hydraulic diameter of 0.079 m. It is mounted on a vertical rotating disk whose diameter is 2.5 m and maximum rotation speed about 160 RPM. Honeycomb devices are fitted at the inlet to smooth out disturbances in the flow and at the outlet to minimize the effects of cross flow. The mass flow is provided by means of
a centrifugal blower for stationary measurements, while a throttling valve is used when rotation effects provide the requested flow conditions. It is measured using a Venturi tube. Electrical power and measured signals are passed to the rotating frame of reference with a 10 channel slip-ring.
Aerodynamic measurements are performed by means of Time-Resolved Particle Image Velocimetry. Accurate time series of 2D relative velocity vectors fields are recorded with a compact laser diode module and a high speed camera, mounted on the rotating disk. The laser light is coupled on a fiber optics cable. Images are stored in the internal memory of the high speed camera during rotation. Indium Tin Oxide layers are used to heat up the channel walls up to 80°C preserving optical access as well as PIV signal-to-noise ratio. Time Resolved PIV can therefore be performed while heating the flow. Heat transfer measurements by means of Liquid Crystals or an IR camera can provide detailed local heat transfer coefficient distributions in rotation.