| Heart failure is the end stage of the development of heart disease.For this kind of disease,the effect of drug treatment is not ideal,and heart transplantation is considered to be the most effective treatment.Due to the limited number of heart donors,which can not meet the clinical needs,more and more scholars turn their research focus to mechanical circulation assisted therapy represented by artificial heart pumps.As the core part of an artificial heart pump,impeller provides power for blood inflow.However,the shear stress caused by high-speed rotating impeller on blood will lead to hemolysis,thrombosis,and other blood damage problems,which seriously affecting the health of patients.Therefore,the development of a centrifugal artificial heart pump that can meet patients’ requirements and reduce the incidence of hemolysis and thrombosis is the focus of current research.This paper focuses on the magnetic levitation centrifugal artificial heart pump design,hydrodynamics simulation of magnetic levitation centrifugal artificial heart pump,the construction of hydraulic performance test platform and the performance evaluation of artificial heart pump.The main research work are as follows:(1)The parameters of impeller and volute of artificial heart pump are calculated by using the velocity coefficient method of pump similarity theory,and the three-dimensional model and related technical parameters of artificial heart pump are determined.Firstly,the main parameters of impeller and volute of artificial heart pump are calculated by velocity coefficient method.Secondly,considering the actual use of the pump,the size and structural parameters of the impeller are modified.With the help of cfturbo software,the initial model of impeller and volute is obtained,which is imported into SolidWorks software to generate entity and other related processing,and the complete model of impeller and volute is obtained.Then,the magnetic flux of the permanent magnet used in the subsequent experiments is calculated,which provides support for the selection of permanent magnet.Finally,the structure and parameters of the original model are summarized.(2)Based on the computational fluid dynamics simulation software FLUENT,the effects of three blade structural parameters,namely blade outlet angle,blade outlet width and blade thickness,and the design of splitter blade on the shear stress distribution and hydraulic performance of centrifugal artificial heart pump were simulated and analyzed.A group of blade structural parameters with better performance were obtained.Firstly,the straight blade impeller is used as the original model to extract the basin model and complete the simulation analysis.Secondly,according to the simulation results of the original model,the blade outlet angle in the range of 15° to 90°and a level every 15°,the blade outlet width in the range of 1～9 mm and a level every 1 mm,and the blade thickness in the range of 1～4 mm and a level every 0.5 mm were selected respectively.The influence of different blade structure parameters on the shear stress distribution and hydraulic performance of the pump was analyzed.Then,the impeller with splitter blade is simulated.Finally,a set of structural parameters of centrifugal artificial heart pump with good performance are obtained;that is,the blade outlet angle is 60°,the blade outlet width is 6 mm,and the blade thickness is 2.5 mm.Based on the optimized model,a set of centrifugal artificial heart pump solid model is processed for the subsequent hydraulic performance test to verify the simulation model’s effectiveness.(3)The hydraulic performance test platform of magnetic levitation centrifugal artificial heart pump was built,the hydraulic performance test of artificial heart pump was completed,and the hydrodynamic simulation model was verified.Firstly,the requirements of hydraulic performance test platform are analyzed,and the hydraulic performance test platform of centrifugal artificial heart pump is built.Secondly,the hydraulic performance test’s experimental scheme was established,and 40%aqueous glycerol solution was used instead of blood.Five groups of impeller speeds of 1500 r/min,1700 r/min,1900 r/min,2100 r/min,and 2300 r/min were selected,and the flow rate,inlet and outlet pressure of each level were tested every 0.5 L/min,and the hydraulic performance curve of the pump was drawn.Finally,the hydraulic performance test points are simulated.By comparing the simulation results with the experimental results,it is found that the relative error of the head of each flow measurement point is less than 15%,which is within the acceptable range of error.The validity of the hydrodynamics simulation model is verified.In this paper,a magnetic levitation centrifugal artificial heart pump is designed,which considers both the shear stress distribution and the hydraulic performance requirements of the pump.A set of hydraulic performance test platforms is built,the hydraulic performance experiment of the artificial heart pump is completed and hydrodynamic simulation model of the centrifugal artificial heart pump is verified.This research has certain theoretical significance for the design and performance evaluation of magnetic levitation centrifugal artificial heart pumps. |
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