Optimal Design Method and Preliminary Testing Verification of Miniature Cryogenic Centrifugal Pump Impeller

High-efficiency miniature cryogenic centrifugal pumps have important applications in the fields such as cryogenic propellant storage on-orbit,and liquefied natural gas or hydrogen filling.The impeller is the core component of centrifugal pumps,which directly affects the pump’s pressure head,efficiency and stability.Its optimization is the crucial part of the design of miniature cryogenic centrifugal pumps.At present,such an optimization usually adopts the model scaling method and the velocity modulus method based on the unitary theory and the similitude theory,with the assistance of numerical simulation or engineering experience.To save R&D costs and shorten the development period,the present study used CFD simulation to verify the similarity of the head curve of cryogenic centrifugal pump with two flowing media:liquid nitrogen and water,and proposed the relationship between other characteristic curves and the medium physical parameters.The easy-to-make 3D printed resin impeller was used to optimize the normal temperature fluid test of the impeller of the miniature cryogenic centrifugal pump.Through comparison and iteration,the optimal impeller with 6 blades and 90°blade wrap angle was determined under the synergic constraints of pressure head,flow rate and efficiency,which could be replaced with metals and applied to low temperature cases.The experimental results confirmed that the rapid iterative optimal design method is feasible and practical for the impeller design of the miniature cryogenic centrifugal pumps.