의료용 Magnetic Fluid Linear Pump 개발

Abstract

Magnetic fluid is liquid, so it moves under the external forces. It is also rigid under the magnetic field enough to maintain against the external forces. This very special characteristic can be applied to the various types of actuators or sensors. In this thesis, the linear pump by using magnetic fluid was developed for medical purpose. the advantages of the MFLP (magnetic fluid linear pump) is that it could pump the non-conductive, non-magnetic liquid such as insulin or blood because of the segregation structure of the magnetic fluid and pumping liquid by thin rubber. The sequential currents are needed to produce pumping forces. The excessive forces at pumping moment could cause the medical shock, and weak forces at intermediate moment could cause the back flow of the pumping liquid. So, the ripples of the pumping forces need to be controlled for the medical application. In this device, the pumping force and pumping speed could be controlled by current scheme.

In this thesis, the method to compute the pumping forces of the MFLP is derived. The change of magnetic fluid surface according to the driving currents could be obtained by magneto-hydrodynamic analysis so that pumping forces could be computed by integration of the surface moving to the pumping direction at each moment. Optimum design using 3-D finite element method with hydrodynamic analysis was performed. The actual MFLP with 12mm diameter was made and tested for experiments. The effects of driving current and frequency on the pumping forces and pumping speed were analyzed and compared with experimental measurements.