Design And Characteristics Of Magnetic Bearing System For Axial Flow Maglev Blood Pump

Heart failure caused by a variety of cardiovascular diseases has seriously threatened human lives. Blood pump is an effective measure to solve the problem. Maglev blood pump has more advantages, such as no friction, no wear, no mechanical contact and long life. Supporting characteristics of axial flow maglev blood pump depend not only on the structure and control parameters of the system, but also on the hemodynamic characteristics. Research on design and characteristics of magnetic bearing system for axial flow maglev blood pump has important theoretical and practical value.For the existing problems in the practical application of blood pump. we regard axial flow maglev blood pump as the research object. A hybrid magnetic levitation supporting structure consists of radial permanent magnetic bearing and axial hybrid magnetic bearing for axial flow blood pump has been designed. Given the complexity of the magnetic bearing system for blood pump, it is important to understand the mechanism of magnetic levitation for blood pump and improve the performance of magnetic levitation blood pump. The results provide the theoretical basis for the design and clinical application of axial flow maglev blood pump. The main contents of the thesis in this paper are listed as follows:(1) Combined with the principle of magnetic levitation technology and the structure of internal flow channel in axial-flow blood pump, three supporting schemes which can be applied to axial flow blood pump have been probed. In addition, according to the basic performance requirements for blood pump. We choose supporting structure consists of radial permanent magnetic bearing and axial hybrid magnetic bearing.(2) The mathematical model of axial suspension force of radial permanent magnetic bearing and axial hybrid magnetic bearing was derived by static magnetic circuit method and equivalent magnetic charge method. Three-dimensional magnetic model of radial permanent magnetic bearing and axial hybrid magnetic bearing was established by three-dimensional finite element software workbench. Magnetic field lines distribution and magnetic field distribution of radial permanent magnetic bearing and axial hybrid magnetic bearing have been studied. In addition, we have calculated magnetic supporting properties and optimized the structure parameters of magnetic bearing.(3) Numerical simulation of internal flow field in axial flow maglev blood pump by computational fluid dynamics(CFD). Due to the existence of coupling between radial permanent magnetic bearing and axial hybrid magnetic bearing in axial flow maglev blood pump, force balance analysis has been studied. We have also explored coupling characteristics of hybrid magnetic bearing structure.