新型铁路隧道落煤吸尘装置吸煤特性仿真分析与试验验证

摘要

Due to air turbulence, large areas of coal will fall when the special coal-transportation trains pass the tunnel exits and entrances.Aiming at the problems of low efficiency and high cost of manual cleaning for long distance coal cleaning in the tunnel, a new railway tunnel fallen coal dust collection device which was composed of a main conveying coal feeding pipe and multiple branch pipes of coal suction was designed.It was used to clean the small particles and lightweight railway tunnel fallen coal.Firstly, the gas-solid two-phase flow model based on the Euler-Lagrange approach for the design of the main conveying coal feeding pipe was established in the coal conveying pipelines.Secondly, the effect of the coal particles` incident angle and multiple branch pipe spacing on the main coal conveying pipe flow field, which was based on Fluent finite element simulation software, was studied.What was more, the optimal angle of incidence and the optimal value of the number of branch coal suction pipe, which was installed on the main conveying pipe, were analyzed.Finally, the finite element simulation was verified by field test.Simulation and experimental results showed that it was more conducive to the railway tunnel fallen coal transportation when coal particles` incident angle was less than 45° and the branch pipe spacing was in the vicinity of 750 mm.For that when incident angle was less than 45°, the main conveying coal pipe pressure-drop became weaker and particle flow could obtain large horizontal transport velocity.And when the branch pipe spacing was in the vicinity of 750 mm, the horizontal transport velocity had a smaller fluctuation range and the transportation of coal was larger than that of the other groups.The research results are of great significance to improve the structure of the main conveying coal pipe, increase the efficiency of tunnel coal conveying and optimize the railway tunnel coal dust collection device.%由于空气扰动,运煤专用列车途经隧道进出口时会出现大面积落煤现象,针对长距离清理隧道落煤面临的人工清理效率低、成本高等难题,设计了一种由1根主输送煤料管和多根吸煤支管组成的新型铁路隧道落煤吸尘装置,用于清理颗粒小、质量轻的铁路隧道落煤.在对主输送煤料管设计中,首先利用欧拉-拉格朗日法建立了输煤管道中的气固两相流模型;其次基于Fluent有限元仿真研究了煤粒入射角和定长管道上多个支管间距对主输送煤料管内流场的影响,分析煤粒最佳入射角以及主输送煤料管上安装吸煤支管数量的最优值;最后通过现场试验对有限元仿真结果进行了验证.仿真和试验结果表明:煤粒入射角α在小于45°时主输送煤料管压降小,颗粒流可获得较大的水平输送速度;支管间距在750 mm附近时,水平输送速度波动范围小且煤料的输送量明显大于其余各组,更加利于铁路隧道落煤的输送.研究结果对改进主输送煤料管结构形式、提高输送隧道落煤效率以及优化铁路隧道落煤吸尘装置具有重要意义.