高速铁路道砟飞溅产生前后道床间隙对道砟颗粒周围流场与气动力影响
王建凯朱剑月季婧雯卢彦宏
Track Bed Gaps Impact on Ballast Particle Surrounding Flow Field and Aerodynamic Forces for High-speed Railways before and after Ballast Splashing
WANG JiankaiZHU JianyueJI JingwenLU Yanhong
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作者信息:1.同济大学交通学院， 201804， 上海；
2.上海市地面交通工具空气动力与热环境模拟重点实验室， 201804， 上海
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Affiliation:1.College of Transportation, Tongji University, 201804, Shanghai, China;
2.Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems, 201804, Shanghai, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.20231012
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中图分类号/CLCN:O357.1∶U238
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栏目/Col:土建工程
摘要:
［目的］高速列车运行于有砟轨道线路时，在道砟颗粒周围产生的复杂空气流场容易形成道砟飞溅，形成机制尚未明确，有必要对具有间隙的有砟轨道道床面上道砟颗粒周围流场与气动力特性进行分析，以阐明道砟飞溅产生机理和影响因素。［方法］基于延迟分离涡模型，采用计算流体动力学数值模拟道砟飞溅产生前后，流体通过具有道床间隙的有砟轨道结构时道砟颗粒周围流场与气动力特性。［结果及结论］由于道床间隙内存在较强的流动分离和流体相互作用，使得有砟轨道道床面流动呈现不规则发展；与位于道床板结区域道床面上道砟颗粒相比，具有间隙的有砟轨道道床面上道砟颗粒由于受到顶部与底部不同方向流动作用的影响，湍涡运动发展更强，产生了较大的脉动力；当道砟颗粒与道床板结区域道床面之间产生间隙时，受到地面效应影响，道砟颗粒顶部和底部受到流动分离与涡脱落的较强作用，流体流经时道砟颗粒底部剪切层动量转换增加，从而促进涡量输运，使得道砟颗粒所受升力增加显著，导致道砟飞溅现象产生。
Abstracts:
［Objective］ When high-speed trains operate on ballasted tracks, the complex airflow field around ballast particles can lead to track ballast splashing. The formation mechanism of this phenomenon remains unclear. It is necessary to analyse the flow field and aerodynamic characteristics around ballast particles on a ballasted track bed with surface gaps to clarify the mechanism and influencing factors of ballast splashing. ［Method］ Based on the DDES (delayed detached-eddy simulation) model, CFD (computational fluid dynamics) is adopted for numerically simulating the flow field and characteristics of aerodynamic forces around ballast particles, as the fluid flows through a ballasted track structure with bed surface gaps before and after the ballast splashing. ［Result & Conclusion］ Due to the strong flow separation and fluid interaction within the ballast bed gaps, the surface flow of the ballasted track exhibits irregular development. Compared to the ballast particles on compacted ballast bed surfaces, particles located on bed surfaces with gaps are influenced by varying flow directions at the top and bottom, leading to intensified turbulent vortex development and greater pulsating forces. When a gap exists between the ballast particle and the compacted bed surface, the ground effect may cause strong flow separation and vortex shedding at the particle′s top and bottom. As the fluid passes by, the momentum transfer in the shear layer beneath the ballast particle increases, enhancing the vorticity transport. This significantly increases the lift force acting on the ballast particle, resulting in ballast splashing.
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