Effect of Blade Outlet Angle on the Flow Field and Preventing Overload in a Centrifugal Pump

The influence of the blade outlet angle on preventing overload in a submersible centrifugal pump and the pump performance characteristics were studied numerically for a low specific speed multi-stage submersible pump. The tested blade outlet angles were 16°, 20°, 24°, 28°, and 32°. The results show that the blade outlet angle significantly affects the external flow characteristics and the power curve can be controlled to prevent overload by properly reducing the blade outlet angle. Increasing the blade outlet angle significantly increases the low pressure area at the impeller inlet, which makes cavitation more likely. Therefore, β2 = 16° provides the best anti-cavitation flow field. Increasing the blade outlet angle also increases the flow separation near the blade working face, which increases the size of the axial vortex along the blade working surface, which rotates in the direction opposite to the impeller rotation and then extends towards the impeller inlet.