Authors: YD Choi K Nishino J Kurokawa J Matsui
Publish Date: 2004/10/05
Volume: 37, Issue: 5, Pages: 617-630
Abstract
Detailed particleimage velocimetry PIV measurements of flow fields inside semiopen impellers have been performed to understand better the internal flow patterns that are responsible for the unique performance of these centrifugal pumps operated in the range of very low specific speed Two impellers one equipped with six radial blades impeller A and the other with four conventional backwardswept blades impeller B are tested in a centrifugal pump designed to be operated at a nondimensional specific speed of ns=024 Complex flow patterns captured by PIV are discussed in conjunction with the overall pump performance measured separately It is revealed that impeller A achieves higher effective head than impeller B even though the flow patterns in impeller A are more complex exhibiting secondary flows and reverse flows in the impeller passage It is shown that both the localized strong outward flow at the pressure side of each blade outlet and the strong outward throughflow along the suction side of each blade are responsible for the better head performance of impeller A
Keywords: