Study Of Magnetovisous Characterisitic Of Magnetic Fluid And Its Effect On Dynamic Performance Of Micro Differenti Alpressure Sensor

Magnetic fluid is a new material which has both fluidity and magnetism. Owing to theunique feature, it is applied on sensor more and more widely. Dynamic analysis of microdifferential pressure sensor is the key to promote its application, and the viscosity of magneticfluid in magnetic field has important influence on the dynamic performance. So magnetoviscouscharacteristic of magnetic fluid is firstly studied through theoretical analysis and experimentalmeasurement, then a magneto-mechanical strong coupled model of sensor includingmagnetoviscous effect is founded. The dynamic experiments are designed and the influencefactors of dynamic performance are analyzed. It provides theoretical basis of structureoptimizing and practical design of the sensor. Main points of this paper are as follows:(1) The influence factors of the viscosity of magnetic fluid are discussed, such as interfacialactive agent, temperature. The viscosity of magnetic fluid in magnetic field is analyzed in theoryand this changing relationship is achieved.(2) The device is designed to provide an adjustable uniform ac/dc magnetic field based onHelmholtz coils. The experimental measurement is carried out using this device and themagnetoviscous characteristic curve is measured. It provides data for dynamic modeling ofsensor.(3) Considering the magnetoviscous effect of magnetic fluid, a numerical model ofmagneto-mechanical strong coupled of micro differential pressure sensor is established, based onfluid kinematics theory. Based on the model, the magnetic field, and fluid field of magnetic fluidin the sensor are analyzed and simulated.(4) Magnetic fluid suitable for micro differential pressure sensor is selected and itsparameters are measured. The sensor structure and excitation source, such as phase step andsmall sinusoidal pressure sources, are choose to provide the experimental system for the researchof dynamic characteristics.(5) The static and dynamic characteristics of the sensor are measured and analyzed. Thetransfer function and Bode diagram, which show dynamic parameters of time domain andfrequency domain of sensor, are acquired. And the influence factors of dynamic performance arediscussed through simulation and experimental measurement.The magnetoviscous characteristic of magnetic fluid is concerned through theoreticalanalysis and experimental measurement in this paper. It offers the basis for micro differentialpressure sensor and other sensors based on magnetic fluid. The dynamic modeling and experimental study provides theoretical basis to optimize the new micro differential pressuresensor and promote the practicability of it.