Research on the development of magnetically levitated pump using axial type switched reluctance self-bearing motor and radial type magnetic bearing

In devices used in the semiconductor industry, medical equipment industry, etc., there is a need for clean liquid transfer without sliding. This paper proposes a magnetic levitated regenerative pump using an axial type switched reluctance self-bearing motor (ASRSBM) and a radial type magnetic bearing (RMB) that does not use permanent magnets in the rotor. Computational fluid dynamics (CFD) of the pump and magnetic field analyses of ASRSBM and RMB were performed to examine the feasibility of the proposed magnetically levitated pump. CFD results of the pump showed that a flow rate of 5 L/min and a pressure of more than 10 kPa could be achieved when the rotor impeller rotation speed was 2000 rpm. It could be verified that the pump designed with two inlets and two outlets reduces the hydrodynamic forces and torques in x, y, z, tx, and ty directions associated with the magnetic support. The driving torque of about 0.09 Nm is required to rotate the rotor impeller. As a result of magnetic field analyses of ASRSBM, it was found that the driving torque, magnetic suspension force and magnetic suspension torque fluctuate during rotor rotation, and that those force and torques are generated in approximately proportion to the square of the magnetomotive force. Although magnetic levitation control is required to adjust those force and torque for each rotation angle of the rotor, we believe that the designed ASRSBM has sufficient driving torque, magnetic suspension force, and magnetic suspension torque. Magnetic field analysis results of RMB shows that the designed RMB has sufficient radial magnetic suspension force, axial passive magnetic support force and passive magnetic support torque. It is believed that a magnetically levitated pump using an axial-type switched reluctance self-bearing motor and a radial type magnetic bearing is quite feasible.