【摘要】 活塞风是真空管道运输内流场的主要气动特征,掌握活塞风的基本特征和变化规律,是合理有效控制管道流场的基础.文中采用计算流体力学方法,结合动网格技术,分析、探讨了活塞风的产生机理,气动特性和真空度、阻塞比、行车速度等作用条件对活塞风的影响.研究发现管道中的空气在车辆行驶过程中会被压缩、膨胀,产生压缩波和膨胀波并对车辆的行车阻力产生影响;通过不同真空度、阻塞比和行车速度的系列组合计算,发现车辆的行车阻力会随着阻塞比的增大、压强的上升、速度的提高而变大,当速度提高到一个阈值时,车辆行车阻力的上升开始变缓.更多还原

【Abstract】 Piston wind is the main aerodynamic characteristics of the flow field in the evacuated tube,and thus grasping the basic characteristics and variation rules of the piston wind is the basis of a reasonable and effective con-trol of the flow field of the tube. In this paper, the influences of piston air generation mechanism,aerodynamic characteristics and degrees of vacuum,blockage ratios, driving speeds and other conditions on the piston wind were analyzed and discussed by using the methods of computational fluid dynamics and dynamic meshing. This study finds that air in the pipeline is compressed and inflated during the running of the vehicle, producing compression and expansion waves and affecting the vehicle’s driving resistance;Through a comprehensive analysis on a series of combined calculations for different degrees of vacuum,blockage ratios and driving speeds,it is found that the vehicle’s driving resistance increases with the growth of the blocking ratio,pressure, and speed. Further,when the speed increases to a threshold,the increase of the vehicle’s driving resistance begins to slow down.更多还原