Temperature Field Analysis And Current-receiving State Safety Assessment Of Pantograph Slide

With the enhancement of China's comprehensive national strength,the rail transit system has been continuously improved.The Pantograph-OCS system is one of the essential parts of the high-speed railway.And for the pantograph slide,as the key part of Pantograph-OCS system,its performance of current-receiving will have a major impact on the train operation.Most of the current research is to study the existing slide defects,but there are few related researches on preventive maintenance.This paper takes the slide of the pantograph as the research object and determines the safety evaluation index system of the slide current-receiving state combined with the field data and related standards.Finally,the paper establishes temperature-based slide current-receiving state safety assessment model through fuzzy analytic hierarchy process.The specific research contents are as follows:(1)The heat source of the slide under the current-receiving state is studied.Based on the finite element simulation model,the equivalent heat flux is considered as the equivalent load,and the feasibility of the method is verified by experiments.Based on this,the main heat sources of the pantograph slide are analyzed,including friction heat,contact resistance heat and off-line arc heat.The heat resistance of the body resistance is negligible.The above work lays the foundation for subsequent research.(2)The temperature field of the slide under the state of current-receiving is studied.The temperature field of the sliding plate under static current-receiving,dynamic current-receiving and offline current-receiving are studied in detail.The materials,traction current,contact pressure,running speed,convective heat transfer coefficient,thermal conductivity and offline state are analyzed.The influence of the temperature rise of the slide is obtained.The results show that under the static current-receiving state,the volume of the high temperature region of the slide is inversely proportional to the thermal conductivity.The temperature rise of the slide is proportional to the parking current,inversely proportional to the parking pressure,and the slide can withstand large currents in a short time by comparing the steady state and the transient temperature field.In the dynamic state of current-receiving,the temperature rise of the sliding plate is proportional to the traction current,and inversely proportional to the convective heat transfer coefficient and the thermal conductivity.When the current is small,the friction heat accounts for the main part of the heat source.At this time,the contact pressure is higher and the temperature is higher.When the current is large,Joule heat accounts for the main part of the heat source.At this time,the contact pressure is higher and the temperature is lower.In addition,it was found that the temperature rise and temperature fluctuation of the slide are inversely proportional to the speed when the current was 500A.Under the condition of offline current-receiving,the temperature rise of the slide is obvious,and both exceed the melting point of the slide.The offline time and offline times are important factors,but the temperature will drop sharply after the off-line arc disappears.According to comprehensive analysis,the temperature rise of the pure carbon slide is higher than that of the metal-impregnated carbon slide under most working conditions.(3)A safety assessment about the state of the slide was carried out.Based on the research results of the temperature field of the slide,the fuzzy analytic hierarchy process is used to establish the safety assessment model of the current-receiving state.The reliability of the model is verified by an example,which provides a theoretical basis for the preventive maintenance of the skateboard.