Research On Low Frequency Micro Pressure Generator Of Magnetic Fluid

Magnetic fluid is a kind of functional material of superparamagnetic solid-liquid two-phase colloidal solution.Its unique properties make magnetic fluid open up the field where solid magnetic materials can not be applied.Under the external magnetic field,the magnetic levitation performance of magnetic fluid could changes with the magnetic field.Pressure generators are widely used in industrial research and mechanical control in modern industrial fields.Micro pressure generators can calibrate the parameters of precision pressure sensors(such as sensitivity,accuracy,etc.),test the performance of piezoelectric materials,and realize remote isolation control.In view of the high frequency of output pressure signal,the need for external mechanical excitation source and the difficulty of mechanical control of these traditional pressure generator,a magnetic fluid low frequency micro pressure generator based on the first-order levitation principle is proposed,which uses current to control output pressure signal.The main research contents are as follows:(1)Measurement and study of magnetic properties of magnetic fluids.The magnetization curves and saturation magnetization of five kinds of magnetic fluids with different carrier fluid were measured by vibrating sample magnetometer,and the magneto-viscous characteristic curves were measured by rotating viscometer.The mechanism of magnetocaloric effect was analyzed,and the influence of the inherent properties of magnetic fluids on the output pressure signal was studied.(2)Design for the model of low frequency micro pressure generator based on magnetic fluid.The working magnetic field is generated by electrifying the parallel double solenoid,and the axial magnetic field of the coil is deduced and calculated.Considering the current carrying capacity of copper-cored enameled wires,magnetic cores are placed inside the shell to reduce magnetic flux leakage and improve the utilization rate of electromagnetic energy.Optimize the structure parameters of the pressure generator and determine the optimal structure of the magnetic fluid low frequency micro pressure generator.According to Bernoulli equation,the magnetic buoyancy of magnetic fluid under non-uniform magnetic field is obtained,the expression of output micro-pressure is deduced,and the working principle of magnetic fluid micro-pressure generator is expounded.(3)Simulation for magnetic field and magnetic force of magnetic fluid micro pressure generator.The simulation model was built by using the finite element software,and the magnetic field distribution in the model and the magnetic force distribution in the magnetic fluid were calculated.The average magnetization of magnetic fluids is calculated according to the magnetization curves measured.The theoretical values of output pressure are calculated by using magnetic pressure,which provides comparative data support for experimental measurements.(4)The experimental study of magnetic fluid micro pressure generator.The experimental platform is built and the acquisition system is designed.The output pressure is detected by pressure sensor.The pressure signal is collected by data acquisition instrument and the pressure waveform is displayed synchronously in the software.Static and dynamic experiments were carried out to test the performance of the device with different current waveforms.The output pressure waveforms were recorded.The input-output characteristic curves were obtained and the influencing factors were analyzed.Experiments show that by adjusting the input current,the magnetic fluid micro-pressure generator can output the low-frequency micro pressure signal with the frequency ranging from 0 to 10 Hz and the amplitude ranging from 0 to 3N by adjusting the input current.