The fabrication of parts by metal additive manufacturing may reduce environmental impact, cost, lead time, and other factors compared to traditional fabrication processes. In particular, several studies have shown that the fabrication of impellers, one of the key elements of turbomachinery, by wire arc additive manufacturing (WAAM) can improve the fabrication process compared to traditional fabrication methods. However, there are problems that have not been discussed in the analyses conducted in these studies with regard to the relationship with the hydraulic performance of the impeller. As the mechanical design in industrial turbomachinery requires appropriate evaluation and determination of impeller hydraulic performance and fabrication methods, it is important to clarify these relationships for industrial applications of WAAM.
In this study, an analysis was conducted for low-solidity axial-flow impellers with a focus on the number of blades. Two aspects were analyzed for axial flow impellers with different numbers of blades. First, an evaluation of the fabrication method by WAAM in the fabrication of impellers was conducted. Second, the pump performance wass measured for a centrifugal pump with axial-flow impellers installed as an inducer to evaluate the hydraulic performance. In addition, these results were analyzed comprehensively. The conclusion is that there is a trade-off between the fabrication process advantage of WAAM and pump suction performance.