Influences of Variable-pitch Blade on the Screw Centrifugal Pump Axial Force

Using the structure and size of type 150×100LN-32 centrifugal pump,according to the vane profile parameter equation group for variable-pitch screw centrifugal pump,eight screw centrifugal pumps with variable screw pitch are designed.By taking eight screw centrifugal pumps with different pitch as the object and selecting solid-liquid two-phase flow of clear water and sandy water as the medium,the time-averaged continuity equation with relative coordinates and the N-S equation are established on the basis of FLUENT software.And standard k-e equation turbulence model,unstructured tetrahedral mesh and SIMPLE algorithm are used to carry out numerical simulation,and then axial force with different pitch is calculated after obtaining the pressure distribution of the screw centrifugal pump.Based on this,comparison is made between the experimental measurement value and the calculated pressure difference between import and export of the screw centrifugal pump with equal pitch,thus indirectly verifying the accuracy of making use of numerical simulation to calculate the axial force.The change trend and rule of the axial force under different pitch with different flow,different volume fraction and with clear water as medium are researched.Through data analysis,it can be seen that the size of the axial force of screw centrifugal pump is affected by many factors,but variable pitch of the impeller alters internal flow field,it plays a decisive role in the size of the axial force of screw centrifugal pump,the axial force shows a certain degree of convexity with the curve of the pitch changing.For different parameters,reasonably designing the blade pitch has important significance to improving the reliability and stability of screw centrifugal pump.