PIV Measurement of Wakes Past Stator Wheel Inside Air Test Turbine VT-400 in Two Axial×Tangential Planes

Abstract

VT-400 is a single-stage test turbine working with ambient air located at the University of West Bohemia in Pilsen. Inside this turbine, we perform a PIV (Particle Image Velocimetry) measurement of the flow field in two planes oriented in axial × tangential direction. There planes are located between the stator wheel and rotor wheel; first one is near the hub, second one at the middle of blade height. The spatial distribution of velocity fluctuations displays system of wakes and jets oriented diagonally over the studied area. The jets are represented by higher mean velocity and lower turbulence, the wakes oppositely. The spatial size of fluctuations is analyzed in terms of autocorrelation function: the size of correlated region is comparable with the wake width, additionally, there is apparent a wave in the stream-wise direction. At different turbine working parameters, we observed at least two distinct wavelengths. The neighboring wakes do not interact in the limits of studied areas.