Numerical Simulation of the Tip Leakage Vortex Control by the Novel Shaped Tip Clearance of a NACA 0009 Hydrofoil

Abstract

In order to suppress the tip leakage vortex, a new tip clearance structure based on Gaussian function is proposed in this paper. Three tip clearance models with different Gaussian function amplitudes are designed. The SST-CC turbulence model is used to numerically analyze the effect of novel shaped tip clearance on tip leakage vortex, streamline, vortex intensity, turbulent kinetic energy and pressure. The results show that the new tip clearance structure has a cutting effect on the main tip leakage vortex and reduce the vortex intensity, but a new tip leakage vortex also appears. The energy loss caused by the new tip leakage vortex increases the turbulent kinetic energy of the flow field. The new tip clearance structure can reduce the low pressure area near the leading edge of the hydrofoil, increase the pressure. In addition, the biggest increase amplitude of lift-drag ratio is 1.12 %. This study can provide a new idea for the tip leakage vortex suppression and operation stability improvement of hydraulic machinery in practical engineering.