Investigation of flow pattern and hydraulic performance of a centrifugal pump impeller through the PIV method

The objective of this study is to analyse the quantitative relationship between the local Euler head distribution and the internal flow in a centrifugal impeller and provide guidance for the design specifications of inverse design methods. The local Euler head at the inlet is mainly affected by the clockwise vortex on the blade suction side. At the outlet, it is affected by the relative motion of clockwise and counterclockwise vortexes. The effect of the two types of vortexes on the local Euler head makes the pump head almost constant under deep part-load conditions, proving that the impeller has an effective diameter. The mean local Euler head distribution along the impeller passage is closely interrelated with the flow pattern. The position in which the mean local Euler head increases fastest coincides with the radial position of the clockwise vortex centre. The position of its maximum value is consistent with the radial position of the end of the clockwise vortex. The position of its maximum value moves towards the inlet as the flow rate decreases, confirming the impeller has an extreme impeller diameter. The inflection points of the mean local Euler head ratio curve correspond to the appearance of vortex structures. (C) 2020 Elsevier Ltd. All rights reserved.