地铁车辆悬挂参数优化与动力学性能评价方法

地铁车辆虽然分为A型和B型两大类,但各城市地铁车辆的技术与结构型式仍存在较大差异。目前对地铁车辆的动力学性能评价尚没有统一的方法,因此对各种形式的地铁车辆方案的对比也就没有一个统一的基础和前提。探讨利用线性化技术对地铁车辆悬挂参数进行快速优化的方法,并在大量干线机车车辆试验与仿真基础上,建议以一种线路不平顺条件作为这种方法的评价基础。此可用于不同方案地铁车辆的动力学评价。

无砟轨道底座板离缝对路桥过渡段动力学性能影响分析

桥台背路基面工后沉落导致无砟轨道底座板出现局部离缝甚至翻浆,是既有高速铁路无砟轨道过渡段典型病害现象。针对路桥过渡段线路结构及不平顺特点,构建了支承刚度和差异变形沿纵向变化的动力学分析模型;运用车辆-轨道-路基耦合动力学理论,分析了路基与桥台交界处工后差异沉降引起的无砟轨道板底座离缝,对车体垂向加速度、轮载力及减载率、钢轨与底座板动位移及路基面动应力等关键指标的影响,讨论了在桥台背设置钢筋混凝土过渡搭板的改善效应。研究表明:(1)400 km/h设计速度条件下,过渡段动力学性能指标随桥台背路基面工后沉落呈非线性劣化趋势,依据高速铁路无砟轨道与路基结构的动态验收技术标准,路桥交界处差异沉降应控制在2~3 mm以内;(2)在过渡段的台背铺设刚性搭板,可有效改善无砟轨道板底支承条件,显著降低动力响应指标幅值,克服现行设计规范容许5 mm差异沉降的不利影响。

重载铁路T梁桥病害对车桥系统动力性能的影响

为明确重载铁路桥梁横隔板损伤成因及多重病害对车桥系统动力性能的影响,以朔黄铁路一座混凝土简支梁桥为研究对象,分析线桥偏心和支座脱空对横隔板受力性能的影响,基于桥梁振幅、加速度、车辆轮重减载率、脱轨系数及车体加速度分析多重病害作用对车桥动力响应的影响。结果表明:线桥偏心和支座脱空是影响跨中和端横隔板损伤的重要因素,横隔板损伤程度随线桥偏心及支座脱空程度的增大而增大;线桥偏心与横隔板损伤耦合作用下车桥动力响应有所增大,对桥梁横向振动产生的不利影响较大;当支座脱空达到一定程度且横隔板发生破坏时,列车平稳性能下降程度较大。

大型风力机三维空气动力学数值模拟

采用数值模拟的方法,对三种风力机叶片的空气动力学性能进行研究。计算得到了旋转功率随着来流速度的变化曲线,并将所得结果与基于动量叶素理论的工程设计方法结果、风洞实验结果和风场实测结果进行对比。计算结果体现了CFD方法解决这种问题的有效性。所用的数值模拟方法可以广泛地应用到风力机设计和气动性能评价中,所得结果可作为叶片动态特性及气弹稳定性分析的载荷而被应用于风力机性能和可靠性的评估当中。

A novel experimental system for performance evaluation of water powered percussive rock drill

A set of water powered excavation test system was developed for the comprehensive performance testing and evaluation of water powered percussive rock drill indoors. The whole system contains hydraulic power section, electronic control system, test and data acquisition system, and assistant devices, such as guideway and drilling bench. Parameters of the water powered percussive rock drill can be obtained by analyzing testing data, which contain impact energy, front and back cavity pressure, pressure and flow in each working part, drilling velocity, frequency and energy efficiency etc. The system is applied to test the self-designed water powered percussive rock drill SYYG65. The parameters of water powered percussive rock drill with impact pressure of about 8.9 MPa are 58.93 J for impact energy, and 8.97% for energy efficiency, which prove the effectiveness of system.

Evaluation of the Thermodynamic Performance of the Traditional Passive Systems

The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.

基于NREL PHASE VI风力机数值模拟的湍流模式研究

该文采用数值模拟的方法,分别使用S-A、标准k-ε、RNG k-ε和SST k-ω四种湍流模式,对NREL PHASE VI风力机的空气动力学性能进行研究。计算涉及六种速度的来流工况,将轴扭矩、叶片截面压力分布和表面极限流线等计算结果与实验结果进行了对比,并分析了不同湍流模式对计算结果的影响。