Research on tip leakage vortex characteristics of axial-flow circulating pumps under unpowered driven conditions

Abstract

To explore the flow characteristics around the tip clearance and the evolution of tip leakage vortex, this paper adopted the delayed detached eddy simulation model to calculate the blade tip region and employed the vorticity transport equation to analyze the forms and strength of tip leakage vortex. It is found that under the effect of tip leakage vortex, the unsteady flow at blade edges are serious under unpowered driven condition. Tip leakage vortex is generated from the leading edge of the blade. From the leading edge to the trailing edge of the blade, the intensity of tip leakage vortex gradually decreases and the generation frequency gradually increases. The core intensity of tip leakage vortex at L1 to L5 points decreases gradually, with a decreased range of about 24.8%, 34.4%, 55.03% and 60.48%.