Research on the Theory and Design Methods of the New Type Submersible Pump for Deep Well

Abstract

Submersible pump for deep well, widely used in the countryside, mines, geothermal utilization and so on, are the main equipment for pumping underground water. Due to the working conditions, the pump diameter is limited by the well diameter, and the single-stage head designed by traditional methods is low. In order to increase the single-stage head, the maximum diameter design method of impeller was created for the first time. The impeller front shroud diameter is almost equal to the inner casing diameter, and the back shroud diameter is almost the average of the impeller front shroud diameter and the guide vane shroud diameter. The blade extends to the impeller inlet to lengthen the back shroud streamline, which could prevent the back flow at the impeller outlet, and the front shroud is designed in a cone shape to make the outlet streamline upward, by which the pump efficiency increases. A new return guide vane with twisted inlet and 3D curved surface was designed to reduce the cost, and the hydraulic loss. The self-balancing design method of impeller axial thrust was accomplished by using the end-face seal at the impeller inlet and adopting the sliding fit between the pump shaft and impeller; the impeller axial thrust is self-balanced because the areas of the impeller front shroud and back shroud are almost equal. The interior flow was simulated based on Fluent RANS CFD, both numerical simulation and test results showed that the performance of the new type well pump was better than the traditional products. A series of submersible pumps for deep well were designed, manufactured and tested, compared to the similar products at market home and abroad, the single-stage head increases 20% to 50%, the efficiency increases 3% to 9%, and the whole axial length and weight decreases around 1/3.