Development Of Microwave Deicing Device For Railway Tunnel

In the northeastern region of China,the infiltration of water at the top of the tunnel will freeze into ice in the winter,it is easy to make the catenary short circuit,and affects the safety of electrified railway tunnels.The current deicing method is artificial deicing in the train running gap,they clear the ice at the top of the tunnel which will affect the safety of the catenary equipment.This creates a great deal of risk when the staff hits the ice picks and usually needs to close the catenary power supply,which affects the orderly operation of the train.In this paper,a non-contact remote microwave heating scheme is proposed to prevent the surface of the tunnel from penetrating the water at low temperatures.Firstly,according to the principle of microwave heating,the principle of horn antenna,the working principle of magnetron and the theory of rectangular waveguide,a suitable microwave de-icing device is designed,which can be arranged on the walls on both sides of the tunnel and keep enough safe distance.Then the complete model of antenna and concrete is established,and the power loss density in concrete is obtained by software simulation.Then,through the experiment,the temperature rise of the antenna diameter and the wet concrete is 2 meters.The microwave source of the horn antenna is lkW magnetron.The experimental results show that the maximum temperature of the concrete surface rises from 17.5℃ to 30.8℃ after 90 minutes,and rises by 2.2℃ on average every 15 ℃ minutes.The temperature rises by 6.5℃ in the initial 30 minutes,and then the temperature rise rate gradually decreases status.During the entire heating process,the initial ambient temperature was 18.1 and the temperature after the end of the experiment was 20.2℃.The experiment proves that the long-distance microwave heating de-icing scheme has a certain feasibility.Finally,in order to further improve the absorption efficiency of the microwave at the top of the tunnel,spraying a layer of absorbing material on the surface of the tunnel wall can increase the absorption capacity of the surface to the microwave and reduce the reflection coefficient of the microwave.The reflection coefficient of the wet concrete coated with absorbing material to microwave is deduced by the theory of depleted transmission line.The results show that the reflection coefficient of the polarized wave is less than that of the polarized wave under the same angle of incidence.According to the parameters of the absorbing material provided by a company,the different thickness absorbing materials are calculated The relationship between the reflection coefficient and the incident angle is combined with the simulation results and the actual situation.The 2mm thickness absorbing material is the best,and the relative complex permittivity of the absorbing material is calculated.The influence of the reflection coefficient on the microwave has a higher absorptive capacity and a low reflection coefficient.