Stereo PIV measurement of vortices in a model pump intake

Abstract

In the present paper, in order to improve and understand of various vortices which form in pump intake, a stereo PIV (Particle Image Velocimetry) technique has been used to investigate the vortex flows in a model pump intake comprising a vertical intake pipe with a bell mouth in a horizontal hexahedral intake under conditions of consistent flow rate and different water level. Two different flow regimes are observed for two cases: a “critical water level (CWL)” for a critical flow rate (case 1); a “higher water level” for a consistent flow rate with previous one (case 2), and the velocity vector, streamline and vorticity distributions on selected measurement sections are analyzed systematically. Comparing the experimental results between case 1 and 2: the number and strength of the vortex decrease with the increase of the water level on selected measurement sections of the free surface, one sidewall and floor. Moreover, there is not any distinct vortex formed on the section of another side wall for two cases neither. The number of vortex on the section of the back wall for case 1 is more than that for case 2, but the strength and the scale for case 1 are lower than that for case 2 on the same section.