The Simulation Of Microwave Deicing In Electrified Railway Tunnels

In the winter,due to the low temperature,the crack of the tunnel at the top of the electrified railway tunnel is easy to form a tunnel hanging ice,with the continuous flow of water,the hanging ice is getting longer and longer,the insulation distance with the contact network is shorter and shorter,which creates a great threat to the safety of tunnel power supply.Therefore,to solve the tunnel deicing problem has a very important significance for the safe operation of the electrified railway.Based on the disadvantages of current artificial deicing and equipment deicing,the article proposes to apply microwave heating technology on the electrified railway tunnel deicing.The method emits microwaves through the antenna to heat the tunnel cracks in the water at the seepage of the concrete,making the water seepage temperature rise.When the temperature rise of more than 5 ℃,the temperature of the water seepage area will cross range of-5 ℃～0 ℃ to prevent water from freezing,which achieves the purpose of tunnel anti-icing.The main research work is as follows:Firstly,based on the theory of microwave heating,the principle and advantage of tunnel deicing are briefly described.According to the theory of electromagnetic field,the microwave power loss equation is deduced,and the factors influencing the microwave absorption capacity of the material are pointed out.Combining the propagation characteristics of electromagnetic wave in the medium,the wave equation of microwave propagation in concrete is deduced.According to the law of thermodynamics,the thermal differential equation of heat transfer in concrete is deduced,and the thermal boundary condition is given according to the actual situation of tunnel deicing.Secondly,according to the simulation assumptions and the actual situation of the tunnel,the microwave deicing simulation model of the tunnel is established,and the temperature field distribution of the microwave deicing model at 2.45GHz and 5.8GHz is simulated respectively.The temperature distribution of the path temperature and the temperature of the reference point were analyzed,and Comparing the microwave de-icing efficiency between the two.The results show that under the same conditions,the microwave deicing efficiency of 5.8GHz is 2.3 times of 2.45GHz.Finally,the effects of antenna input power,tunnel wind speed,concrete water content and ambient temperature on the efficiency of tunnel microwave deicing were studied.The tunnel input power is proportional to the efficiency of tunnel microwave de-icing.The wind speed and ambient temperature of the tunnel mainly affect the convective heat transfer between the concrete surface and the air.The efficiency of tunnel de-icing decreases with the increase of wind speed and the decrease of ambient temperature.The influence of tunnel wind speed is greater than ambient temperature.The water content of concrete mainly determines the dielectric constant and loss tangent of concrete,which has the greatest influence on the efficiency of microwave dewatering.The higher the water content of concrete,the higher the efficiency of microwave deicing.