Research On The Physical Properties Of Suspended Micro-particles Under Complex Electromagnetic Environment In Space

With the rapid development of industry,transportation and urbanization,the content of suspended atmospheric micro-particles is increasing in the space environment.Because of small particle size,large number,wide surface area and complex chemical composition,atmospheric micro-particles have not only a bad impact on the atmosphere and the ecological environment,but also a much greater risk to health compared with coarse particulate matter of the same mass.Therefore,the frequent occurrence of particulate pollution has become the focus of the society in recent years.There is an urgent need for research on the cause and evolution of atmospheric suspended micro-particles.However,over the years,most studies about the causes and distribution rule of atmospheric suspended particulate pollution have focused on meteorological factors and weather conditions,ignoring the electromagnetic radiation in the same spatial and temporal environment.The rapid development of industry and production technologies has led to the widely use of electronic information equipment in various fields such as electricity,communication,transportation,medical care and life,etc.These electromagnetic radiation sources with different power intensities or different frequency bands form a complex electromagnetic environment with high density and strong coupling,which may make unpredictable effects on the materials placed in the environment.The survey found that few scholars at home and abroad have conducted interdisciplinary and interdisciplinary research on the combination of micro-particle pollution and space electromagnetic radiation.Therefore,the project team creatively proposed the research objective of the impact mechanism of space complex electromagnetic environment on the physical and chemical properties of suspended micro-particles and the convincing evaluation method of the model,and obtained the support of the national science and technology frontier innovation project.We explore the influence mechanism of complex electromagnetic environment on the physical properties of micro-particles by analyzing the composition and distribution characteristics of suspended micro-particles as the starting point.Through the combination of theoretical analysis,numerical simulation and experimental verification,we carry out systematic and in-depth research on a series of issues such as the working mechanism,dynamic characteristics and experimental verification of complex electromagnetic radiation environment affecting the physical properties of micro-particles.The main contents and achievements of this study are summarized as follows:Based on the basic characteristics and harmfulness of atmospheric suspended micro-particles,the distribution map of safety factor of Shaanxi power grid under different meteorological disasters is obtained by combining the geographic information system with the meteorological monitoring data of Shaanxi Meteorological Bureau in recent ten years.A comprehensive fault assessment model of power grid transmission lines under the combined action of multiple meteorological factors such as lightning strike,strong wind,icing and micro-particle pollution based on fuzzy analytic hierarchy process is proposed.Compared with most single factor assessment models,this model effectively solves the uncertainty of meteorological disasters and the problem of non-independence,and significantly improves the accuracy and reliability of transmission line risk assessment.It is more suitable to predict the operation risk of transmission lines in different regions and seasons.The composition of the complex electromagnetic environment in space is systematically studied.Through the continuous and long-term monitoring of the automatic electromagnetic radiation monitoring station in Shaanxi Province,the electromagnetic spectrum characteristics and distribution laws of the space environment around the monitoring station are revealed.In order to verify the influence mechanism of space complex electromagnetic environment on the physical characteristics of suspended micro-particles by experiments,a method combining physical and simulation is proposed to creatively build a complex electromagnetic environment that covers 1～10GHz frequency band multimode reconfigurable.The simulation environment presents a multi-dimensional and three-dimensional working environment similar to the actual application environment.Based on Newton’s second law,the dynamic model of suspended micro-particles(particle size≤108)in turbulent field and electromagnetic field is established.A system simulation model of gas-solid two-phase flow under the action of external magnetic field is constructed by considering various forces such as Brownian force,fluid drag force and magnetic field force.The influence of magnetic field,magnetic field action time,particle charge and other factors on the trajectory of micro-particles is solved by grid division method,and the internal mechanism of the interaction between suspended micro particles and space electromagnetic irradiation is obtained.Under the action of a magnetic field,the physical properties such as the trajectory and temperature gradient of the micro-particles change significantly.On the basis of theoretical analysis and system simulation,a new type of experimental control system suitable for the extensive study of space electromagnetic wave radiation effect is designed and built,and multiple sets of control experiments on the physical characteristics of micro-particles under different electromagnetic environments are carried out.In order to comprehensively analyze the influence of electromagnetic environment on the microscopic physical properties of micro-particles,an experimental result processing method combining microscopic visualization and image processing technology is proposed,which can intuitively and efficiently extract massive picture information,and realize the detailed analysis of the change trend of multiple physical parameters including particle number,particle size,particle surface area and particle morphology.At the same time,time series analysis,significance analysis,correlation analysis and other mathematical statistical methods are used to study the distribution characteristics of micro-particle mass concentration and number concentration under different electromagnetic irradiation intensities.The experimental results show that the particle mass concentration is different under the action of different modal magnetic fields.The frequency and power of electromagnetic wave affect the decreasing speed of particle mass concentration.The physical properties of micro-particles vary with the intensity and time of electromagnetic irradiation.This study relies on the strong support of the Science and Technology Commission’s"Interaction Principle and Experimental Verification of Complex Electromagnetic Waves and Physical Characteristics of Haze"(1716315XJ00400209,"Physical Characteristics,Application and Experimental Verification of Haze Particles in an Autonomous and Controllable Environment"(1816315LZ00100302 and other projects,and explores the influence of space complex electromagnetic environment on the physical characteristics of atmospheric suspended micro-particles,which can provide important theoretical and experimental guidance for formulating prevention and control strategies and applications of micro-particle pollution.