As an innovative technology of nuclear power, magnetically suspended high-temperature molten salt canned motor pump (referred to as molten salt canned motor pump) can be used in the fourth generation molten salt reactor (MSR). Improving pump performance via hydraulic optimization design is significant to fourth-generation nuclear power technology.

This study aims to investigate the influence of different working fluids on the hydraulic optimization design of magnetically suspended high-temperature molten salt-canned motor pumps and provide suggestions for the optimal design of magnetically suspended high-temperature molten salt-canned motor pumps.

Firstly, ANSYS CFX software was employed to perform a numerical simulation of a magnetically suspended high-temperature molten salt canned motor pump. Based on response surface methodology (RSM), approximate models between significant parameters and optimization objectives were established. Then, taking the efficiency and head as optimization objectives, a non-dominated sorting genetic algorithm II (NSGA-II) was used to design the magnetically suspended high-temperature molten salt canned motor pump under molten salt and water.

Compared with water working fluid, the optimization space of the pump under molten salt working fluid is larger. When the efficiency of the optimization model under the two working fluids is the same, the impeller inlet diameter and the blade outlet placement angle of the molten salt optimization model are reduced, whereas the impeller outlet width and the diffuser throat plane width are increased. The efficiency of the finally determined molten salt optimization model is increased by 0.75% and the head is raised by 0.078 2 m whilst the efficiency of the water optimization model is increased by 0.55%, and the head is reduced by 0.035 9 m.

The research results of this study can be used to guide the hydraulic structure design of a magnetically suspended high-temperature molten salt-canned motor pump.