ISSN   1004-0595

CN  62-1224/O4

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基于Archard磨损理论的表面织构对碳刷/集电环载流磨损特性研究

Surface Pattern Pair Based on Archard Wear Theory Study on Current-Carrying Wear Characteristics of Carbon Brush/Collector Ring

  • 摘要: 水轮发电机组在运行过程中,碳刷在电、机械和热耦合作用下易因磨损过度及磨粒堆积而影响机组的发电效率. 通过建立碳刷/集电环瞬态耦合有限元模型,结合Archard磨损模型进行载流磨损行为的数值仿真,研究表面织构对碳刷/集电环载流磨损性能的影响,并采用试验方法对仿真结果进行验证. 试验结果表明:载流工况下,碳刷的磨损峰值主要分布在织构周围以及边缘区域;表面织构占比率为25%时,散热性能与基体强度达到协调优化,磨损体积显著降低. 低电流密度下因接触压力不足导致非均匀磨损加剧,而在高电流密度下因局部温度剧烈升高导致材料剥落加剧. 仿生序构排列织构能优化表面接触状态,有效缓解应力集中并增强散热性能,从而显著降低碳刷磨损率.

     

    Abstract: During the operation of hydro-generator set, the carbon brush is prone to excessive wear and accumulation of abrasive particles under the action of electrical, mechanical and thermal coupling, which will affect the power generation efficiency of the unit. By establishing a transient coupling finite element model of carbon brush/collector ring and combining with Archard wear model, numerical simulation of current-carrying wear behavior was carried out to study the influence of surface pattern on current-carrying wear performance of carbon brush/collector ring, and the simulation results were verified by experimental method. The experimental results showed that the wear peak value of carbon brush was mainly distributed around the pattern and the edge area under current load condition. When the surface pattern ratio was 25%, the heat dissipation performance and the matrix strength were coordinated and optimized, and the wear volume was significantly reduced. At low current density, non-uniform wear was aggravated due to insufficient contact pressure, while at high current density, material spalling was aggravated due to sharp rise in local temperature. Biomimetic ordering pattern could optimize the surface contact state, effectively alleviate stress concentration and enhance heat dissipation performance, thus significantly reducing the carbon brush wear rate.

     

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