铁路隧道空气附加阻力及坡度折减系数研究

采用非恒定流理论,提出了隧道空气附加阻力的计算方法,分别推导了列车部分进入隧道、全部进入隧道、部分驶出隧道的空气附加阻力解析计算公式;研究了列车在隧道内不同运行时刻的空气阻力变化规律,并全面阐述了隧道长度、隧道净空断面、列车长度、列车运行速度等因素对隧道空气阻力的影响;分析研究了隧道坡度折减系数与隧道长度、净空断面、机车牵引能力的相关性,得出了大断面隧道的坡度折减很小或无需折减的结论,对长大及特长隧道的选线设计具有极其重要的指导意义。

Study on Additional Air Resistance and Gradient Reduced Coefficient of Traction in Railway Tunnel

Based on the unsteady flow theory, the calculation method on additional air resistance in tunnel is put forward,and its calculation formula are deduced for the cases: part of the train in tunnel, all train in tunnel and partial exit from the tunnel respectively; the changes rule of air resistance for the train at different running moment in tunnel is studied, and the factors affecting air resistance in tunnel, such as length of tunnel, tunnel section, length of train and train running speed are elaborated; the correlation of railway tunnel gradient reduction coefficient with the tunnel length, section and locomotive traction power is analyzed, and a conclusion is drawn that for large cross section tunnel the gradient reduction is very small or no reduction, it has important significance for railway geometric design of long and extra-long tunnels.