Optimization of a single stage double suction centrifugal pump

Aljaž Škerlavaj, Mitja Morgut, Dragica Jošt and Enrico Nobile (Kolektor Turboinstitut, University of Trieste)

CHALLENGE - Double-suction centrifugal pumps allow transportation of greater flow rates than single-entry pumps because they are less prone to cavitation problems. The purpose of this work is to compare different RSM (Response Surface Methods) for a case of optimizing a double-suction centrifugal pump. We recall that RSM represent an economical alternative to the more expensive 3D CAE models, CFD in this case. The objective here is pump efficiency.

SOLUTION - For the impeller optimization of the pump, the shape of the meridional channel was based on past experience and was not modified during the optimization procedure. The blade geometry was generated from a certain set of input parameters provided to an in-house code that uses an inverse-singularity method. The data was exported to ANSYS DesignModeler, where a 3D geometry of an impeller was automatically created. ANSYS CFX software was used for CFD simulations. The optimization process was driven by modeFRONTIER optimization platform. After the CFD simulations were performed on a set of initial design parameters (DOE), subsequent CFD simulations were performed during optimization process with MOGA-II algorithm for 10 generations. Numerous RSM algorithms, available within the modeFRONTIER optimization software, were trained on nine initial variables.


BENEFITS - The initial and optimized geometries of the impeller, characterized by 100 % and 100.9 % relative efficiencies respectively, are illustrated above. Furthermore, the five most influential design variables by order of importance were: blade trailing edge inclination angle at hub, location of leading edge at hub in the meridional view, length of the blade at hub in the polar view, location of leading edge at shroud in the meridional view, length from the axis of rotation to the impeller blade trailing edge, at hub.