EFFECTS OF CORIOLIS-FORCE ON FLOW IN ROTATING DIFFUSERS

To investigate the coupled effects of secondary flow stability (or ins tability) due to Coriolis force, and adverse pressure gradient on the flow in a rotating diffuser of low aspect ratio, quantitative experime nts were performed. The diffuser had parallel end walls and straight s ide walls, which could vary its included angle up to 18 deg. Pressure, mean velocity, and turbulence intensity were measured with a pressure transducer, hot-wire anemometers, and a transmission system of electr ical signals from a rotating apparatus to the stationary system. Exper imental results indicate the formation of a stable large separated flo w region on the suction side and a through-flow region on the pressure side. The flow pattern was steady, and once the separation occurred, the change of the angular velocity had little or no effect on the mean velocity and turbulence intensity profiles at the midheight of the ro tating diffuser.