Study on influences of blade deflection on flow characteristics around inverted-umbrella impeller

Use the CFX software to numerically simulate the inverted umbrella Landy 7 and Landy 7-15 impeller with a blade deflection of 15 degrees. The influence of blade deflection on flow characteristics around the impeller, the variations of pressure difference, liquid velocity, and liquid phase turbulence following the change of blade deflection angle were discussed, which was then verified by the PIV test. The results showed that the surface disturbance performance of Landy 7-15 was better than Landy 7. The negative pressure area on the back of the impeller of Landy 7-15 was more evenly distributed, with an enormous pressure difference, higher liquid velocity, and more obvious turbulence than Landy 7, which can improve the impeller’s aeration efficiency. The turbulent value of Landy 7 was slightly higher than that of Landy 7-15 in the region near the bottom. Landy 7 also has stronger pushing force and agitation on water. This study could provide technical references for the structure optimization of the impeller.