The Theoretical Research On Magnetic Fluids Acceleration Sensor

Based on the second order buoyancy principle of magnetic fluids, which is In the magnetic field, magnetic fluids can suspend the permanent magnet with density larger than fluids, a magnetic fluid acceleration sensor was designed with a permanent magnet suspended in magnetic fluids as inertial mass. The signal was detected by a pair of inductive loops.The structure parameters of the loops were designed and the materials used in the sensor were selected including the permanent magnet and magnetic fluid. Structure parameters of the sensor were designed. Finally, a really sensor model was built base on the above design workThe energy method which connected the Thermodynamic functions and the mechanical work of surface force was used to determine the stress tensor expression in magnetic fluids. So the general solution of the force suffered by the object immersed in magnetic fluids can be obtained. Adopting the above formulas, the second order buoyancy phenomenon was proved and the position of permanent magnet immersed in magnetic fluids was determined, by using numerical methods. The Navier-Stokes equation of magnetic fluids was deduced and simplified by using the magnetic levitation and viscosity model. According to the N-S equation, the magnetic field and flow field coupling problem which is of great importance in magnetic fluids acceleration sensor study was discussed and a key conclusion was achieved that the key factor influence the sensors'controllability is the magnetic fluids viscosity in gaps, which can provide clues for the search of controllable parameters.