【作者】 万军；

【导师】 熊红兵；

【作者基本信息】 浙江大学 ， 流体力学， 2012， 硕士

【摘要】 随着我国高速铁路的飞速发展,列车运行速度不断提高,铁路沿线地理环境,列车运行工况越来越多变,越来越复杂。列车在极端恶劣天气如强侧风、暴风雨等工况下行驶时,列车气动特性变化较大。为使高速列车在各种工况下安全运行,很有必要研究列车在极端恶劣气候天气下运行的气动特性变化规律。本文基于定常不可压N-S方程、标准k-ε两方程湍流模型、以及欧拉双流体多相流模型研究了某型高速列车在强侧风及暴风雨条件下的气动力特性。采用商用软件FLUENT对列车进行数值模拟,分析了列车周围流场的压力、速度、流线等的分布情况,以及在强降雨和强侧风耦合作用下,列车气动力的变化规律。列车的侧向力和升力都随侧风的风速增大而增大。在强侧风情况下,列车侧向力和升力急剧增大,这有可能导致列车失稳甚至倾覆。随着风速增大,列车阻力先是逐渐增大；当侧风速度达到15m/s左右时,列车阻力最大；当侧风速度继续增大时,由于头车负阻力的贡献增加而使整车阻力逐渐减小。研究表明,在强降雨及强侧风同时作用的条件下,列车的升力、侧向力、侧偏力矩等影响列车行车安全的气动参数都比仅有侧风的工况大,因此降雨会进一步危害列车的行车安全。根据列车的倾覆理论,通过动力学力矩平衡原理,对列车列出动力学力矩平衡方程,求解该方程即可得出列车临界安全行车速度与侧风之间的关系式,从而得到列车在侧风和暴风雨条件下安全行驶的倾覆临界速度。临界速度减小代表列车更易倾覆、列车安全行车域更小。研究结果发现,相比仅有侧风的天气情况,暴风雨使列车安全域减小10%-20%。通过对列车在恶劣气候条件下的气动性能计算和限速研究,为列车在恶劣气候下的安全行车提供了一定的参考依据。更多还原

【Abstract】 With the rapid development of China high-speed railway and the continuous increase of the train speed, the train safety operation under the diversified climate conditions are become more and more complicated in different region and season. The train aerodynamic characteristics change in extreme weather working conditions, for example the crosswind, the rainstorm and so on. It is considerably concerned to study the aerodynamic characteristics and safe train operation of high-speed train under extreme weather conditions.Based on the steady-state incompressible Navier-Storkes equation, standard k-ε turbulence model, and Eulerian two-phase model, the aerodynamic performance of a high-speed train under rainstorm and strong crosswind conditions are modeled using the Eulerian two-phase model in this paper. The impact of heavy rainfall on train aerodynamics is investigated using commercial software FLUENT, coupling heavy rain and a strong crosswind. The lift and side forces increase with the cross wind speed. The drag force increases firstly and then decreases with the cross wind speed, reaching maximum at about15m/s. Results show that the lift force, side force, and rolling moment of the train increase significantly under rain conditions than no rain condition.Meanwhile, a quasi-static stability analysis using the moment balance is utilized to determine the limit safety speed of train under different rain and wind levels. Results show that the train is more easily to overturn on the inner curve track. The train limiting speeds under rain decrease about10%～15%than that of without rain, which means that the train is more easily to overturn under strong rain condition.更多还原