| Chemical method is the most common and remarkable method for solving thescaling problem in industrial circulating cooling water. In recent years, the physicalmethod to remove scale is paid more and more attention. Although the application ofphysical anti-scaling products is not very wide, the fact of scale inhibition effect isbeyond doubt.We use Material Explorer, molecular dynamics simulation software, to study effecton both scale inhibition and scale removal by magnetic field. In molecular dynamicssimulation, we mainly inspect the changes of the diffusion coefficient of watermolecules and the radial distribution function between ions within the magnetic field.The study find that the scale inhibition effect is embodied in certain conditions, namelytemperature or other physical quantities affect the scale inhibition effect. In addition, wefind that the scale inhibition effect can be achieved at temperatures below the thresholdtemperature value, once the temperature is higher than the threshold temperature, thescale inhibition effect almost disappears. Finally, we study the scale removal effect bymagnetic field. We find that no matter how high we increased the flux density, magneticfield direction, and temperature respectively, the descaling effect of magnetic field hasnot appeared, which denies the descaling effect of magnetic field.In order to obtain bipolar rotating magnetic field, this paper presents a new devicemodel. We compares it with the electromagnetic generator for the advantages anddisadvantages respectively. In this paper, in order to produce the air gap flux density for0.1T, we study the feasibility of two generation device. For the electromagneticgenerator, we focus on the layout of the required current value, cross-sectional area,copper coil layers for obtaining magnetic flux density of0.1T. We found that if thesolenoid current value is120A, cross section is35mm2and coil number is5, the fluxdensity in air gap is0.1T. We study on the relationship between the magnetic inductionintensity with distance and properties of two permanent magnets by using ANSYSsoftware for magnetic field analysis. Research results show that the flux density of airgap is affected by the distance of two permanent magnets, the smaller the distance thestronger magnetic induction intensity. At the same time, permanent magnet remanenceaffects magnetic induction intensity of the air gap, the larger remanence the strongermagnetic induction intensity. If we use the neodymium iron boron permanent magnet type N35, and the two pole distance is3cm, the air gap flux density can reach0.1T.Therefore, in the evaluation of two generation device advanced, economic practicalityand stability, we decided to adopt the way of permanent magnet rotating to producealternating magnetic field. In the mechanical assembly aspect, in order to reduce the airresistance, we select the cylindrical permanent magnet, and the attachment plate alsoadopts a cylindrical one. In order to realize the stepless rotation speed regulation of thesingle-phase asynchronous motor, we use an electronic speed switch, thus the rotatingmagnetic field frequency can also be adjusted smoothly. Namely, the magneticinduction intensity is0.1T, the bipolar magnetic field is attained with adjustablefrequency from40Hz to95Hz.Finally, we used the rotating magnetic field generating device to do scale inhibitionexperiments. First of all, the repeatability of experiments is conducted. In the sameexperimental conditions, we did three experiments, and inspected three groups ofexperimental data. Inspection found that this experimental system owned experimentalrepeatability. Then, we carried out one experiment group of constant magnetic field andfour experiment groups of rotating magnetic field with different frequencies.Experimental results show that, the rotating magnetic field has stronger inhibition effectfor groups with frequency as66Hz,73Hz,90Hz, and the highest inhibition rate reaches33%. The scale inhibition effect of80Hz group is the same as that of the constantmagnetic field group, which indicates that not all frequencies of the rotating magneticfield have high scale inhibition effect. |
