Inter-blade flow analysis of a propeller turbine runner using stereoscopic PIV

The paper presents the averaged velocity field inside the inter-blade channel of a propeller turbine runner measured using a stereoscopic particle image velocimetry (SPIV) technique. In this manner measurements have been performed without any modification of the flow patterns, with the averaged three-dimensional velocity fields reconstructed from phase-averaged acquisition data based on the blade azimuth. Main and secondary flows were analyzed for nine operating conditions, ranging from part to full load. The radial velocities and gradients play major roles in the inter-blade flow development. Using the λ2-definition for vortex detection, leading edge vortices were detected and identified under part load conditions.