Design And Analysis On Anti-galloping Effectiveness Of Low Wind Pressure Positive Feeder Of Overhead Catenary System In Gale Zone Of Lanzhou-Urumqi High-speed Railway

The Xinjiang section of the Lanzhou-Urumqi high-speed railway passes through the four gale areas of Yan Dun,Bai Li and Da Ban Cheng etc.Some sections have an average of more than 200 days of 8-level winds every year.Lanzhou-Urumqi Railway has an accident where a strong wind blows over a train.Therefore,the railway construction department built a windshield wall along the railway,but the windshield wall "anti-train but not OCS(overhead catenary system)",that has an acceleration effect on the airflow,that gives rising to waving sharply of AF(Auto-transformer Feeder)wire behind the windshield.It causes discharging between the positive feeder and the protection line,it breaks of the traction substation,which results in fatigue strand breakage of the thread,which increases wear of the fittings,and endangers railway operation safety.In order to ensure the reliability of the traction substation system of the Lanzhou-Urumqi high-speed railway,it is necessary to design a type of low wind positive feeder to reduce the galloping amplitude of the positive feeder and improve the safety of railway transportation.Firstly,which establishes a two-dimensional model of the cross-section of the railway it includes the windshield wall and the routine positive feeder,and utilizes the wind tunnel test device to verify the rationality and correctness of the model established in this research and the simulation method adopted.That divides the grid overall calculation domain,and makes using to fluid simulation software for calculation domain to carry out numerical simulation calculations under different wind speeds.Which compares the wind tunnel test device with the numerical calculation results,it is found that under different environment wind speeds,the wind speed at the positive feeder behind the windshield is about twice the environment wind speed,and the error range between the numerical calculation results and the experimental values is0.2%～0.68%.From the gas tightness of the test device,this error is within a reasonable range,which shows that the model established is reasonable and the simulation method is correct in this study.Secondly,it establishes the central angle θ=30°,36°,45°,60°,90°,r/R=0.10～0.15,a total of 30 different types of low wind pressure positive feeder models.Which implements the aerodynamic characteristics simulation calculation under the wind speed of 6～30m/s and 3m/s at intervals,and the analysis of the calculation results shows that: r/R value is larger and larger,the wind resistance coefficient is smaller and smaller,but when the central angle θ=45°,the wind resistance coefficient of the r/R=0.14 of low wind pressure positive feeder under the wind load of 15～30m/s is smallest in comparison to various types of low wind pressure positive feeder.That compares the average resistance coefficient of positive feeder with the central angleθ=45°,r/R=0.10～0.15 and the routine positive feeder in the entire test wind speed range,positive feeder with r/R=0.14 of resistance reduction rate is the largest,it reaches to 25.68%,it analyzes the flow field around the low wind pressure positive feeder with central angle θ=45°,r/R=0.10～0.15 and the routine positive feeder found that: the positive feeder with r/R=0.14 has two largest vortexes within total objections and close to the positive feeder,which produces a maximum force pointing to the direction of the wind on the positive feeder.Finally,which analyzes strained characteristics of the low wind pressure positive feeder with central angle θ=45° and r/R=0.12～0.14.Carrying out 25% RTS(Rated Tensile Strength)for three-dimensional model free end of r/R=0.12～0.14 low wind pressure positive feeder in the simulation software,and analyzes its deformation and stress changes,the results show that the positive feeder will have a certain axial deformation under the action of 25% RTS,the deformation of the fixed end is the smallest,and the deformation of the free end is larger.The second layer of steel strands sustains most of the axial deformation when the positive feeder is waving,strands of other layers extrude each other in the twist direction to form a stress concentration point.The stress diagram of the positive feeder strands is echelon,and the stress value gets larger and then it gets less and then it gets larger on different sections from the fixed end face to the free end face,the maximum stress of outermost layer strands gets larger with the larger of r/R value.Under the action of axial tension,the displacement of the wire strands increases sequentially from the inner layer to the outer layer.