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| 1 | Numerical study on wake characteristics of high-speed trains显示文摘Intensive turbulence exists in the wakes of high speed trains,and the aerodynamic performance of the trailing car could deteriorate rapidly due to complicated features of the vortices in the wake zone.As a result,the safety and amenity of high speed trains would face a great challenge.This paper considers mainly the mechanism of vortex formation and evolution in the train flow field.A real CRH2 model is studied,with a leading car,a middle car and a trailing car included.Di?erent running speeds and cross wind conditions are considered,and the approaches of unsteady Reynold-averaged Navier–Stokes(URANS)and detached eddy simulation(DES)are utilized,respectively.Results reveal that DES has better capability of capturing small eddies compared to URANS.However,for large eddies,the e?ects of two approaches are almost the same.In conditions without cross winds,two large vortex streets stretch from the train nose and interact strongly with each other in the wake zone.With the reinforcement of the ground,a complicated wake vortex system generates and becomes strengthened as the running speed increases.However,the locations of flow separations on the train surface and the separation mechanism keep unchanged.In conditions with cross winds,three large vortices develop along the leeward side of the train,among which the weakest one has no obvious influence on the wake flow while the other two stretch to the tail of the train and combine with the helical vortices in the train wake.Thus,optimization of the aerodynamic performance of the trailing car should be aiming at reducing the intensity of the wake vortex system. | Shuan-Bao Yao Zhen-Xu Sun Di-Long Guo Da-Wei Chen Guo-Wei Yang | 2013 | Acta Mechanica Sinica2013，29，6： | 19 |
| 2 | 高速列车气动噪声贡献量分析显示文摘建立了3节编组的CRH380B高速列车气动噪声计算模型,包括6个转向架、2个风挡、3个空调机组和1个DSA380型受电弓等细微结构,采用基于Lighthill声学理论的宽频带噪声源模型对高速列车气动噪声源进行识别,基于高阶有限差分法的大涡模拟对高速列车近场非定常流动进行分析,并采用Ffowcs Williams-Hawkings声学比拟理论对高速列车气动噪声进行预测。计算结果表明:远场噪声计算结果与风洞试验结果的最大差值为1.45dBA,因此,高速列车气动噪声计算模型是准确的;对气动噪声贡献量由大到小依次为转向架系统(6个转向架)、车端连接处(2个风挡)、受电弓与空调机组,数值分别为83.58、79.31、74.08、59.71dBA;以受电弓开口方式运行的整车气动噪声贡献量小于闭口方式,最大声压级和平均声压级分别小于0.40、0.31dBA;头车一位端转向架对转向架系统气动噪声贡献量最大,为79.73dBA;对受电弓气动噪声贡献量由大到小依次为:碳滑板、平衡臂、弓头支架、底架、绝缘子、下臂杆、铰接结构、上臂杆、拉杆与平衡杆,数值分别为97.95、93.02、86.63、82.07、79.46、76.85、72.43、66.63、62.02、54.22dBA;在速度为350km·h-1时,受电弓气动噪声存在主频为305、608、913 Hz,且此3阶单频噪声频率是由弓头部位涡流脱落所导致的气动噪声贡献。 | 张亚东 张继业 李田 | 2017 | 交通运输工程学报2017，17，4： | 14 |
| 3 | Simulation of phase transition process using lattice Boltzmann method显示文摘A new lattice Boltzmann model based on SC model, is proposed to describe the liquid-vapor phase transitions. The new model is validated through the simulation of the one-component phase transition process. Compared with the simulation results of van der Waals gas and the Maxwell equal-area construction, the results of the new model have a better agreement with the analytical solutions than those of SC and Zhang models. Since the obtained temperature range and the maximum density ratio in this model are expanded, and the magnitude of maximum spurious current is only between those of SC and Zhang models, it is believed that this new model has better stability than SC and Zhang models. Consequently, the application scope of this new model is expanded compared with the existing phase transition models. According to the principle of the corresponding states in engineering thermodynamics, the simulations of ammonia and water phase transition process were implemented using this new model with different equations of state. Compared with the experimental data of ammonia and water, the results show that the Peng-Robinson is the best equation of state to describe the phase transition process of ammonia and water. Especially, the simulation results of ammonia with Peng-Robinson equation of state have an excellent agreement with its experimental data. Therefore these simulation results have a significant influence on the real engineering applications. | ZENG JianBang LI LongJian LIAO Quan CUI WenZhi CHEN QingHua PAN LiangMing | 2009 | Chinese Science Bulletin2009，54，24： | 8 |
| 4 | Influence of tunnel length on the pressure wave generated by high-speed trains passing each other显示文摘The prediction of the pressure wave amplitude produced when two trains pass each other in the tunnel is important to the train design for airtightness and tunnel conditions in China.In this paper,the key factors of this problem were firstly stud-ied based on theoretical analysis.The equation of the worst tunnel length for the global maximum and minimum pressure values was derived.Then,the influence of tunnel length on global minimum pressure and the critical region in which the global minimum pressure varies rapidly were investigated.Finally,a numerical method based on two-dimensional Na-vier-Stokes equations was established.Typical conditions of two trains passing-by in tunnels of different lengths were simulated.The theoretical and computational results agree with each other closely. | WANG YiWei YANG GuoWei HUANG ChengGuang WANG Wei | 2012 | Science China(Technological Sciences)2012，55，1： | 7 |
| 5 | 高速列车通过隧道时气动阻力特性的CFD仿真分析显示文摘基于可压缩流体的纳维-斯托克斯方程和RNGk-ε模型,以由头车、中间车和尾车3辆车编组的某高速列车1:8风洞试验模型为研究对象,采用计算流体动力学软件(CFD),建立包括车体和走行部的三维非结构化列车表面离散网格模型和列车与隧道、列车与明线空间的组合计算网格模型,研究高速列车通过隧道时气动阻力的时变特性和规律。结果表明:高速列车在车尾刚进入隧道入口时其气动阻力达到最大值,为同样工况下明线运行时的2.5倍;高速列车完全进入隧道后,其气动阻力在一段时问内处于相对平稳期,为明线运行时的1.8倍;之后在隧道压力波的作用下,高速列车的气动阻力会发生准周期变化,变化幅度接近明线运行时的60%;在隧道长度大于高速列车长度的前提下,高速列车通过不同长度隧道时,其进入隧道时的气动阻力最大值均比较接近,而且在隧道内运行时的气动阻力变化特征和幅值也基本相同。 | 王一伟 杨国伟 黄晨光 | 2012 | 中国铁道科学2012，33，B08： | 5 |
| 6 | Torque model of hydro turbine with inner energy loss characteristics显示文摘This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine. | ZENG Yun1,2, GUO YaKun2, ZHANG LiXiang1, XU TianMao3 & DONG HongKui4 1 Construction Engineering College, Kunming University of Science and Technology, Kunming 650051, China 2 School of Engineering, University of Aberdeen, Aberdeen AB24 3UE, UK 3 Computing Center, Kunming University of Science and Technology, Kunming 650051, China 4 Hydraulic Energy Department, Yunnan Electric Power Test and Research Institute, Kunming 650217, China | 2010 | Science China(Technological Sciences)2010，53，10： | 3 |
| 7 | 基于相变过程的格子Boltzmann模型及应用显示文摘基于SC模型提出了一种新的描述气液相变过程的格子Boltzmann模型.通过对单组分相变过程的模拟,验证了该模型的正确性.通过对vdW流体的模拟以及与Maxwell构建原理的对比,发现相对于SC和Zhang模型,新模型能够得到与理论解相近的结果,计算产生的最大伪速度介于SC和Zhang模型之间,但扩大了温度的变化范围,提高了模型的最大分离密度比,使得新模型计算更加稳定,适用范围更加广泛.根据工程热力学中的对比态原理,以工程中常用氨和水两种工质为例,利用新模型分别模拟不同状态方程控制下的相变过程,并与实验值进行了比较,结果表明P-R状态方程更加适合描述氨和水等物质的相变过程,特别地,P-R状态方程模拟结果与氨的实验值更加接近,结果具有重要工程意义. | 曾建邦 李隆键 廖全 崔文智 陈清华 潘良明 | 2010 | 科学通报2010，55，3： | 1 |
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