| Heart failure is the most serious manifestation of heart disease and directly threatens the life of patients.Heart transplantation is the most effective method to treat heart failure at present,but there is a serious shortage of heart donors.Therefore,implantation of artificial heart instead of living heart transplantation has become the first choice to save patients with heart failure.The third generation artificial heart adopts hydraulic suspension or magnetic suspension support structure,which eliminates mechanical wear and reduces the degree of blood damage due to the characteristics of no mechanical contact support.It has become the mainstream trend in the development of heart pumps.However,its magnetic or hydraulic suspension support system still has the problems of large volume and high heat generation,which affects the working performance of heart pumps.Therefore,this paper takes the third generation artificial heart pump as the research object,designs a compact suspension support structure by theoretical analysis and numerical simulation,and analyzes and verifies the working performance of the heart pump under the support structure.Firstly,the driving components and fluid components of the artificial heart pump are analyzed,and two suspension support schemes of the artificial heart pump are proposed.Considering the space limitation of the heart pump,through the comparative analysis of the two schemes,the radial permanent magnet bearing support and axial hydraulic support are finally selected to realize the suspension of the impeller,and the stress of the impeller is analyzed under the condition of multi-field coupling.Secondly,the finite element analysis software ANSYS Maxwell is used to model and calculate the heart pump motor,and the relationship between the axial force of the motor and the axial offset is obtained.In order to balance the axial force of the motor,the structure of radial permanent magnet bearing is designed by combining theoretical analysis and numerical simulation,and the permanent magnet bearing material is selected according to the application conditions of the heart pump.On this basis,the levitation performance of the magnetic levitation supportsystem composed of bearings and motors is analyzed.Thirdly,the blood flow characteristics of the suspension support flow field of the heart pump are analyzed.Starting from the most basic N-S equation of fluid mechanics,a three-dimensional mathematical model of blood flow is established in combination with turbulence equation,and the preliminary design of the hydraulic suspension support structure is carried out.Aiming at high suspension support force,the support force of spiral groove with different structural parameters was studied by using ANSYS CFX flow field analysis software by orthogonal test method,and a set of optimal structural parameters of spiral groove opening mode was obtained.The primary and secondary order of influence of spiral groove structural parameters on the support force of heart pump was obtained by range analysis,and the hydraulic performance and suspension performance of heart pump were simulated and analyzed.Finally,a prototype of the heart pump is made and manufactured.According to the blood circulation circuit implanted in the human body,a performance test bench of the heart pump is set up to carry out hydraulic performance test and suspension test to verify the simulation results and the feasibility of the magnetic fluid suspension support structure. |
