Safety Assessment Of Electromagnetic Exposure Of Superconducting Maglev Train Track Magnets To Passengers

With the rapid development of rail transit technology,the research and development of maglev technology has been continuously promoted,especially the new high temperature superconducting maglev technology has become the focus of various countries in the world.Maglev technology has been widely used,but also attracted public attention to the electromagnetic environment safety of trains.Maglev train has made great progress and accumulation in engineering application,but there are relatively few researches on the effect of electromagnetic environment of maglev train on human body.In this thesis,by using COMSOL Multiphysics finite element simulation platform,reference the federal university of Rio DE Janeiro in Brazil high temperature superconducting maglev train,the vehicle at the bottom of the permanent magnet track as source of electromagnetic exposure,respectively,in order to train both stationary and motion state of condition,the passengers in the car is exposed to the permanent magnet guideway magnetic field body and head area of magnetic flux density and the induced electric field intensity are analyzed.The simulation results were compared with the public electromagnetic exposure limit recommended by International Commission on Non-Ionizing Radiation Protection(ICNIRP),and the electromagnetic exposure level of the permanent magnet guide to the passengers in the car was analyzed.The research mainly includes:(1)This thesis introduces the development history and current situation of superconducting maglev train at home and abroad,as well as the research status of electromagnetic environment of maglev train at home and abroad.The relevant standards of electromagnetic exposure at home and abroad are expounded.The software module used in the simulation is reproduced in the classic case to verify its reliability,which is ready for the simulation analysis of high temperature superconducting maglev train in advance.(2)The working principle of the high temperature superconducting maglev train and the structure of the train body and track are described.The finite element simulation software was used to model the superconducting maglev train and permanent magnet guide rail of the Federal University of Rio de Janeiro,Brazil.According to the fourth-order Cole-Cole model,the electrical parameters of different tissues of the human body are calculated,and the adult human body model is established according to the Chinese adult human body standard,and the three-layer ball model is adopted for the head.Three adult passengers in different positions were placed in the static model.Three dynamic models are established to study the train motion state of three passengers respectively.(3)In maglev train relatively permanent magnet track static state,according to the normal operation condition of the train,namely the suspension height is 5mm,the simulation calculation of electromagnetic exposure in different location of the passengers inside the car body,and to slice the passenger head model,analysis the inner regions of the human head model(brain)in the distribution of magnetic flux density.The influence of different materials on the flux density of the passenger body is analyzed by simulation.Under the condition of magnetic levitation relative to permanent magnet track,the electromagnetic exposure of passengers in the train is simulated when the suspension height is 5mm and the train rotates on the ring permanent magnet track at a speed of 812r/min.The magnetic flux density(B)and the induced electric field intensity(E)of the passenger head tissue are analyzed.Finally,the simulation results are compared with the electromagnetic exposure limits set by ICNIRP to evaluate the electromagnetic exposure of the high temperature superconducting magnetic levitation track.The results show that when the train is still,the maximum magnetic flux density in the passengers sitting directly above the track is the highest,and the maximum magnetic flux density in the passengers sitting directly above the aisle and standing in the aisle is only 45.9% and 14.5% of the passengers sitting directly above the aisle.With the distance between the passenger and the permanent magnet track,the maximum magnetic flux density in the body becomes smaller.When the maglev train is moving,the magnetic flux density and the induced electric field in the body of the passengers sitting directly above the track are the highest among the three passengers.The maximum magnetic flux density and the maximum induced electric field in the passengers standing in the aisle were the smallest among the three passengers.Through comparative analysis,the electromagnetic exposure values of passengers in the superconducting maglev train were all lower than the exposure limits recommended by International Commission on Non-Ionizing Radiation Protection.