Adjoint-Based Topology Optimization for Hydraulic Performance Improvement in Double-Suction Volute Pump

Abstract The increasing demand for high-speed and miniaturized pumping solutions, as well as the need for high efficiency performance, has made a crucial aspect of the double-suction volute pumps design in modern industrial systems. To achieve these goals, the most important requirement is to design the suction passage to generate uniform velocity distribution and pre-rotation to ensure the incidence matching to the blade angle of the impeller leading edge. Previous studies proposed the optimization design procedure of a double-suction pump using DOE (Design of Experiment) with limited design parameters to improve the pump hydraulic efficiency. However, due to its three-dimensional curved free surface configuration, defining the hydraulic shape of suction passage in limited design parameters is challenging. To address this issue, this study introduced the adjoint-based topology optimization method to optimize the suction passage of the double-suction volute pump. This method aims to reduce the computational cost because it is independent from the number of design variables. To control the flow distribution at the outlet of the suction passage, the objective functions such as velocity component and flow angle deviation were implemented, ensuring the flow pattern matching and maximum impeller efficiency. Furthermore, the objectives, such as total pressure loss minimization and flow uniformity were also chosen. A three-dimensional RANS equation was used to solve both flow fields and adjoint dual fields, and the results were validated through numerical simulation and experimental testing. The results showed that the optimal design by topology optimization improved the flow uniformity and the total pressure loss inside the suction passage was reduced, leading to the improvement of suction performance and a slight increase in pump efficiency by 0.2% at the design flow rate compared with the baseline design. Overall, this study demonstrates that incorporating velocity components and pre-rotation flow angle objectives in topology optimization could improve the hydraulic performance of double suction pumps and provide valuable insights for designing more effective and reliable flow passage in a range of applications.