CFD Analysis On The Influence Of The Shape Of Impeller Chamber And Hub On The Hydraulic Performance Of Axial-flow Pumps

The impeller is the core component of the axial flow pump, the performance of the axial flow pump is determined by it directly. The impeller structure parameters have a great influence on the performance of Axial Pump Sets. In the model trial of axial flow pump, the spherical structure of the hub and impeller chamber is easy to adjust the angle of blades. But most small and medium-sized axial flow pump in practical engineering does not need to adjust the blade angle. So a cylinder structure is adopted to design the hub or impeller chamber to reduce economic costs and improve the installation convenience.Based on RANS equations and the standard turbulent model, numerical modeling and mesh generation could be realized by geometric modeling software1CEM, Turbo-Grid and workbench. Three-dimensional incompressible flow field numerical analysis could be simulated by simulated by commercial3D software CFX. Interior characteristics and external characteristic of different scheme (different shape of the hub or impeller chamber) could be carried out.Through analyzing the calculation result with CFX-Post, we could see:1. keep the hub ratio and the hub shape, when the impeller chamber change to cylinder from spherical surface, the head and efficiency of the Axial-flow pump increase at the same discharge. Maximum efficiency point move to the larger discharge point and become larger at the same time;2. when the impeller chamber change to cylinder from spherical surface, area of passage become larger, the velocity get down at the same discharge. According to velocity triangle at the entry, flow angle become smaller, equivalent to incidence angle become larger, airfoil lift become larger. It is equal to blade angle become larger, so head become larger, efficiency point move to the larger discharge point and become larger at the same time;3. based on conclusion1,short the impeller diameter to297mm, its performance is in line with zm50’s;4.keep cylinder impeller chamber, when the hub change to taper from spherical surface, the head and efficiency of axial-flow pump become larger, Maximum efficiency point move to the larger discharge point and become larger at the same time, maximum has increased about1.7%;5.change the impeller chamber to cylinder and short its diameter to297mm,when the hub is taper, its performance is in line with zm50.6.exit section of a cylindrical hub, the hub than shrinking export segment, the axial flow efficiency increases. Optimal operating point efficiency of approximately1.6%.7.spherical impeller chamber housing, the performance at high lift at improving efficiency improved.