横风下复线路堤高度对高速列车气动性能的影响

Influence of double-track embankment height on aerodynamic performance of high-speed train under crosswind

利用Creo软件建立了某型动车组头中尾3车编组和不同高度的路堤模型,通过Fluent软件模拟列车在车速分别为300和350 km·h^(-1),横风风速分别为17.10、20.70、24.40和28.40 m·s;的环境下运行,将获取的高速列车气动力载荷施加到Simpack建立的动力学模型中,计算其动力学性能参数;深入分析了横风工况下高速列车在不同高度复线路堤背风侧运行时车体的压力分布、气流场结构、气动力与风致安全性,并重点探究了头车在不同运行速度和横风风速下的运行安全性。分析结果表明:在相同车速和横风环境下,随着路堤高度的增加,列车受到的侧向力整体呈增大趋势,尾车在横风作用下受到反向侧向力,头车所受侧向力最大,且升力持续增大,中间车所受升力相对较大,尾车所受阻力最大;横风环境下列车压力峰值点位于头车鼻尖处且向迎风侧偏移,各路堤高度工况下气流场结构基本相同,头车背风侧和底部转向架处有明显的涡流,但尾车处的涡流却在迎风侧,这可能是导致尾车反向侧向力的主因;脱轨系数、轮轴横向力、轮轨垂向力和轮重减载率均随路堤高度和横风风速的增大而增大,轮轨垂向力始终在安全限值内,当横风风速分别为24.40和28.40 m·s;时,列车运行速度应分别低于350和300 km·h^(-1),以保证列车行车安全。

Models for embankments with different heights and a specific type of electric multiple units(EMUs) with three vehicles, including a locomotive, an ordinary vehicle, and a caboose, were established with the help of Creo and Fluent to simulate the operation of a train at the speeds of 300 and 350 km·h^(-1) under the crosswind speeds of 17.10, 20.70, 24.40 and 28.40 m·s;, respectively. The obtained aerodynamic loads of the high-speed train were subsequently applied to the dynamics model established using the Simpack to calculate the dynamics performance parameters. The pressure distributions, airflow field structures, aerodynamic forces and wind-induced safeties of the high-speed train running on the leeward side of a double-track were analyzed under different embankment heights in a crosswind environment. Considerable attention was also given to the safety of the locomotive under different operating speeds and crosswind speeds. Analysis results indicate that for the same vehicle speed and crosswind environment, as the embankment height increases, the lateral force acting on the train increases overall, and the caboose experiences an opposite lateral force under crosswinds. The locomotive is subjected to the largest lateral force, while the lift increases continuously. The ordinary vehicle is subjected to a relatively large lift, and the caboose is subjected to the greatest resistance. The pressure peak of the train in a crosswind environment is at the nose tip of the locomotive and offset to the windward side. The airflow field structure remains basically the same regardless of the embankment height. There are obvious eddy currents on the leeward side of the locomotive and the bottom bogie. However, the eddy currents at the caboose are observed on the windward side. They may be the main factor causing an opposite force acting on the caboose. As the embankment height and crosswind speed increase, the derailment coefficient, wheel axle lateral force, wheel rail vertical force and wheel load reduction rate also increase, and the wheel rail vertical force is always within the safety limit. To ensure the safety of the train under the crosswind speeds of 24.40 and 28.40 m·s;, the speed of the high-speed train should be lower than 350 and 300 km·h^(-1), respectively. 2 tabs, 21 figs, 32 refs.