Investigation On Kinetic Characteristic Of Magnetic Fine Particles In High Gradient Magnetic Field

The pollution of particulate matter with aerodynamic diameters<10μm (PM10) has been attracting much attention both inside or outside China. The formation mechanism and the control techniques of PM10 from combustion are being paid much attention by more and more scientific researchers. The combustion of fossil fuels is the main resource of particulate matter in the air, and it's very necessary to study the kinetic characteristic of PM10 from combustion. Lots of researches indicates that fly ash from power plant,which is the main pollution resource, contains much magnetic matter. PM10 from other resources contains certain magnetic matter. The formation theory and control techniques of PM10 from combustion was brought into'973 Program'by Ministry of Science and Technology of P.R. China,and the kinetic characteristic of PM10 in magnetic field was included.A test-facility was founded in this paper to make experimental research in the characteristic of magnetic particles in high gradient magnetic field. So far there've been no experimental methods for the visualization of the characteristic of the microcosmic movement of PM10. Commercial PIV techniques (TSI and DANTEC etc.) can not be used directly in this two-phase flow research. Electrical Low Pressure Impactor was used in the experiment of this paper to measure the number concentration of the particles without and with magnetic field and bar at the outlet of the passage, respectively. Further more, the influence of aerosol flux, magnetic flux of applied magnetic field, the saturated magnetization and the diameter of ferromagnetic wires, and the number of the rows of the bar were taken into account when analyzing the movement of the particles in high gradient magnetic field. The results indicated that decreasing aerosol flux, improving applied magnetic flux, using wires which have higher saturated magnetization,reducing the diameters of the wires and increasing the number of the bar will improve the capture capability of the bars which have ferromagnetic wires.The software Femlab called as multiple physics field coupling analysis was used in this paper to analyze the movement characteristic of the ferromagnetic particles in the experimental section through the mathematical model, which was also deduced in the paper. Computing mesh was generated by the software, and unstructured triangular mesh was utilized here. Lagrange-Quadratic method and Lagrange-P2P1 were used when calculating the static magnetic field and fluid field, respectively. Visualization of the magnetic field,fluid field, particle field was carried out according to the numerical simulation. And it made up the shortage of the experiment in some sense. Meanwhile, qualitative and quantitative analysis was also made to find that the results from both mathematical simulation and experiment accorded with each other in tendency.