The Study Of Magnetic Fluid Sealing Of Vapor Compression Distillation System In Space Station

The vapor compression distillation unit (VCD) is the key equipment in water reclaims system in manned space station project organized currently in china. Its dynamic seal is very important to operation performance, water production and water quality. As the traditional seal can't meet the requirements of zero leakage, long life and high reliability, this project is to design a magnetic fluid sealing structure of VCD under the fully known of pressure resistance and failure mechanism of magnetic fluid seal.This thesis focuses on this target, and completes the following studies:(1) In order to verify the feasibility of magnetic fluid seal used in space station, the experimental device for magnetic fluid seal's pressure resistance and failure mechanism study is designed. Magnetic circuit model of sealing structure is established, and magnetic field strength in the seal gap and other parameters are calculated, magnetic field distribution under pole teeth and leakage position of magnetic flux are obtained.(2) Experiment of distribution shape and movement of magnetic fluid in the sealing gap, sealing pressure test, and mechanism verify experiment are done on the designed experimental device. Experiment founds that:Sealing capability of magnetic fluid seal and the sealing stage are in a linear relationship.(3) Three kinds of hypothesis of sealing mechanism are proposed. Analyze the experimental results and find that gas flowing between stages fulfils the delivery of pressure. Gas flowing model is established, and basic parameters are calculated.(4) According to the magnetic fluid seal design principle, combined with findings of mechanism research, the magnetic fluid sealing structure of VCD in space station is designed.(5) Magnetic field of the structure is simulated by Ansys, Distribution of magnetic field lines, the vector magnetic flux density, magnetic field strength in the gap, sealing pressure are obtained. That means the design is reasonable.(6) Optimization model of magnetic fluid seal is established, Optimize the magnetic fluid sealing structure by Matlab, the objective of reducing the size and weight is reached.