Study On Optimization Of Aerodynamic Self-Cleaning Structure Of Roof Insulator

According to the "Outline of Powerful Nation Railway Advance Planning in the new era",speeding up the breakthrough development of railways and taking the lead in building a modern railway power is the focus of building a country with strong transportation network in the new era.Railway transportation in the new era uses electric traction as the main form of power.Among the main high-voltage power supply equipments of electric locomotives,roof insulators hold the function of bearing and insulating.When the trains are running,the roof insulators are constantly exposed to the impact of the airflow,and under the combined influence of severe weather such as haze,the surface of the roof insulators are likely to accumulate contamination and moisture,which will cause pollution flashover.In order to improve the ability of railway transportation to adapt to harsh weather,this paper optimized the structure of roof insulators based on the principles of aerodynamics,and explored the contamination accumulation characteristics of different roof insulators in the haze environment.These studies can provide important references for the design and improvement of external insulation equipments for high-speed trains.This article first analyzed the airflow around a circular cylinder and the force of the solid particles,and based on the results proposed the optimization strategy of the shape and structure of the roof insulator sheds and core rods;The finite element simulation software was used to analyze the aerodynamic performance of the optimized structure,and the airflow distribution and vortex distribution characteristics of the optimized structure were obtained;Through simulation and test methods,the surface electric field distribution of the optimized structure was calculated,and the dry flashover voltage under different airflow speeds was measured,which proves that the optimized structure has qualified electrical insulation performance.The annular-return wind tunnel system was built,the mixed artificial contamination was used to simulate the haze components,and the contamination accumulation test of the optimized structure was carried out;The contamination accumulation characteristics of the shed surface and the dirt coverage characteristics of the core rod surface were measured;By calculating the wind pressure distribution on the surface of the insulator,the difference between the contamination accumulation characteristics on the core rods and the sheds was analyzed;The high-speed blower gun device was built,and the movement process of the moisture in the haze on the surface of the sheds was analyzed.In view of the serious accumulation of contamination on the side wind surface of the core rod,a further optimization strategy for the surface structure of the core rod was proposed based on the principle of aerodynamics;The finite element simulation software was used to analyze the characteristics of the airflow distribution,vorticity distribution and surface pressure distribution of the optimized core rod;The test was carried out in the annular-return wind tunnel and the contamination accumulation characteristics of the optimized core rod were measured,and the movement process of the moisture on the surface of the optimized core rod was analyzed using the high-speed blower gun device.Considering that the optimized core rod will adversely affect the contamination accumulation on the shed’s surface,based on the principle of hydrophobicity,a further optimization strategy for the shed’s surface structure was proposed and the static contact angle and contact angle hysteresis of the optimized shed are measured;The contamination accumulation characteristics of the optimized sheds are measured by the annular-return wind tunnel,and the self-cleaning ability when water drops hit the sheds was analyzed.The results show that the optimized aerodynamic roof insulator has a high airflow velocity around itself,and a small vortex in the airflow field.The contamination accumulation on the surface of the aerodynamic roof insulator is significantly reduced and the accumulation saturation value is low.The moisture in the haze is not easy to accumulate on the surface of the aerodynamic roof insulator and cannot form a water film.The surface of the optimized insulator can achieve a certain degree of self-cleaning ability under the influence of the airflow of the train.