Subtractive/Additive Rapid Prototyping of a Curve Spacer for Centrifugal Pump Impeller: Design, Manufacturing, and Simulation Analysis

This paper presents methods of rapid prototyping design and manufacturing used in the development of a centrifugal pump impeller with curved spacer (CS). In this research subtractive and additive rapid manufacturing methods were applied to create complex curved spacer profiles for testing as part of geometry optimization process for a high speed and high flow rate centrifugal pump impeller. Seven models for the curved spacer were designed and each model was integrated with the bare impeller separately for simulation analysis. One design was selected for manufacturing with applying subtractive and additive processes. In subtractive manufacturing method, the raw material was removed from a solid shaft by a cutting process under digital control from a computer file. The complexity of the modified impeller spacer profiles required the use of expensive CNC machining with five axis capability. This technique offers the possibility to produce components of increased complexity whilst ensuring quality, strength, performance and speed of manufacture. In additive manufacturing method a 3D printing machine was used with heating the filament polylactic acid wire to build the prototype layer by layer. The ability to manufacture complex spacer profiles that are robust enough for testing in a rapid and cost effective manner is proved essential in the overall design optimization process for the specified pump impeller with six blades. The manufacturing methods employed for curved spacer thickness, spacer angle, profile and required power consumption were analyzed. In this work the results of the simulation modelling were compared to the experimental data. The final recorded results demonstrated that the impeller’s development with the innovative curved spacer design and manufacturing have the potential to achieve sensible improvement of total pump efficiency at different flowrates.