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Search Results: 1 - 10 of 3468 matches for " 游溢 "
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带协同流壁面射流的数值模拟模型及影响规律
钟永力,晏致涛,,
- , 2018,
Abstract: 针对下击暴流中的壁面射流模型,采用4种不同湍流模型的CFD方法比较分析了带协同流壁面射流在不同发展阶段的平均风剖面及雷诺应力等流场特性.结果表明,使用修正的雷诺应力模型(RSM)得到了与实验较为吻合的结果,对带协同流壁面射流的数值模拟是有效和准确的.使用修正的RSM分析了不同协同流和射流风速比β对壁面射流平均风剖面、壁面摩擦因数等参数的影响.分析结果显示:当β值从0.1增大到0.3时,相同位置处的速度越大,最大速度衰减越慢,壁面摩擦因数减小越快,内、外层相互作用越弱.
For wall jet model with co-flow used in the downburst, four turbulent models were used to analyze the flow characteristics of the wall jet with co-flow, including the average wind velocity profile and Reynolds stress at different developing stages. The results show that the prediction of the modified Reynolds stress model (RSM) is in close agreement with the experimental data. The modified RSM is effective and accurate for the wall jet with co-flow, and it is also used to investigate the effects of ratio of the wall jet bulk velocity and co-flow velocity on the wall friction coefficient and mean wind velocity profile. It is found that when β increases from 0.1 to 0.3, the mean velocity increases with the velocity ratio, the maximum velocity degradation becomes slower gradually, the wall friction coefficient decreases more rapidly, and the interaction between inner layer and outer layer is decreased.
圆钢管格构式塔架气动力的数值模拟
,晏致涛,陈俊帆,李文胜,何成,闫渤文
- , 2018,
Abstract: 输电塔结构具有高柔、轻质和小阻尼的特性,因此风荷载是输电塔结构的主要控制荷载.以苏通大跨越输电塔结构作为工程背景,开展了一系列的刚性节段模型风洞试验,研究了在光滑均匀流作用下的圆钢管格构式塔架气动力特性.并基于计算流体力学(Computational Fluid Dynamics,简称CFD)技术,采用大涡模拟(Large-eddy simulation,简称LES)方法分别对圆钢管格构式塔架节段的顺风向、横风向和扭转向风荷载特性进行计算,并将计算结果与实验值以及各国规范进行了对比.此外,讨论了湍流度分别为5%、10%、15%和20%四种情况下的三分力系数.结果表明,本文的数值模拟结果与各国规范及风洞试验结果较为一致,且湍流度的变化对结构三分力系数的脉动成分有显著影响.此外,从节段模型的表面风压力分布情况来看,最大正压出现在迎风面的主管正面和辅材相交节点的正面,最大负压出现在主管的侧面.通过涡量图对节段模型流场结构分析发现,x向的涡量离散程度更高,而y和z向上涡量分布更加均匀连续.本文的研究成果对实际工程中的圆管截面格构式结构风荷载评估具有重要的参考价值.
Due to the high flexibility, light self-weight and low damping ratio of the power transmission tower, wind loads are the dominant lateral loads at its design stage. This study conducted a series of rigid model tests on the aerodynamic forces of circular steel tubular lattice structures under smoothly uniform flow conditions in the wind tunnel laboratory, and the models were fabricated based on a super high-rise power transmission tower in Huainan-Nanjing-Shanghai UHVAC transmission line. The Large-eddy simulation(LES) of lattice structures were performed to simulate the aerodynamic forces in the longitudinal, transverse and lateral directions, and the results were compared to the corresponding specifications in the available wind codes or standards. In addition, the aerodynamic forces of lattice structures were simulated by using LES under the flow conditions with turbulence intensities of 5%, 10%, 15% and 20%. The results showed that the numerical results were in relatively reasonable agreement with the experimental measurements, and the incoming turbulence intensity had indispensable influences on the fluctuating components of the aerodynamic forces. Moreover, the maximum positive pressures were observed on the windward surface at the junction of the strut and the diagonal member, while the maximum negative pressures were recorded on the lateral surface of the strut. Furthermore, the vorticity analysis showed that the vorticity in the x-direction was more scattered while those in the y- and z- directions were more uniform and continuous. The findings of this study are of great use for evaluating the aerodynamic forces of circular steel tubular lattice structures in the practice constructions.
平面壁面射流风场作用下建筑物表面风压数值模拟
钟永力,晏致涛,?覮,,赵爽
- , 2019,
Abstract: 采用平面壁面射流模拟下击暴流的出流段风场,通过协同流模拟下击暴流水平移动,基于计算流体动力学方法,采用雷诺应力模型(RSM)的Stress-Omega模型模拟了稳态下击暴流的平均风剖面,并在风场中建立高层建筑物模型,研究下击暴流风场中高层建筑物表面风压分布特性.结果表明,采用平面壁面射流模型得到的水平速度竖向风剖面与下击暴流理论风剖面以及试验结果吻合较好,壁面射流模型风场中建筑风压分布特征与冲击射流风洞试验一致;迎风面风压系数随着顺流向距离的增加而不断减小,随着射流入流湍流强度的增大而减小.当下击暴流风剖面半高值大于1.45倍建筑物高度时,壁面射流风场中建筑风压分布与大气边界层风场中类似.协同流对结构中下部风压分布影响较大,而风向角对最大风压的影响不大.
The downburst outflow wind field was modeled by plane wall jet, and the co-flow was used to simulate the translation of downburst. Based on the computational fluid dynamics(CFD) method,the velocity profile of steady downburst was simulated with Reynolds stress model(RSM),and then a high -rise building model was put into the wind field to study the surface pressure distribution. The velocity profile from the numerical analysis results matches well with the empirical models as well as the plane and radial wall jet experiments. The pressure distribution characteristics of the building model in plane wall jet flow is in good accordance with the results of the imping jet experiment. The pressure coefficient decreases when the downstream distance increases. The pressure coefficient decreases with the increase of wall jet inlet turbulence intensity. When the half-width of the downburst velocity profile is higher than 1.45 times height of the building, the pressure distribution in wall jet flow is similar with that in boundary layer. Co-flow mainly has influence on the structure in the lower part. The wind direction of wall jet has little effect on the maximum pressure.
基于壁面射流的下击暴流非稳态风场大涡模拟
Large Eddy Simulation of Unsteady Downburst Outflow Based on Wall Jet Model

钟永力, 晏致涛, 王灵芝,
ZHONG Yongli
, YAN Zhitao, WANG Lingzhi, YOU Yi

- , 2018, DOI: 10.3969/j.issn.0258-2724.2018.06.013
Abstract: 为研究边界层风洞中下击暴流大缩尺比试验的可行性,基于冲击射流和壁面射流模型,采用大涡模拟方法,分析了静止和移动下击暴流的风场特性;通过与Wood模型、Oseguera模型、Victory模型以及经典壁面射流实验对比,验证了采用冲击射流和壁面射流模型在模拟稳态下击暴流出流段的一致性和有效性;在壁面射流模型入口处引入3种速度函数,模拟了下击暴流非稳态风速时程.研究结果表明:与冲击射流一样,无协同流壁面射流能够有效地模拟静止下击暴流的稳态出流段;当冲击射流平移速度为出流速度的15%时,其最大水平风速较静止冲击射流增大了15.8%;协同流速度为射流速度的19.2%时,其最大风速较无协同流壁面射流增大了16.9%,带协同流壁面射流能够有效地模拟移动下击暴流;提出的速度入口函数模型作为壁面射流入流条件,能够较为真实地模拟出Andrews AFB下击暴流非稳态风场.
:The feasibility of a large-scale experiment for downburst in a boundary layer wind tunnel was investigated. Large eddy simulation (LES) was employed to investigate the characteristics of stationary and travelling downburst using the impinging jet and wall jet methods,respectively. The velocity profiles from LES were compared with those obtained from the Wood model,the Oseguera model,the Victory model,and the classical wall jet experiment to verify the reasonableness of the two methods. Then,three time functions of the inlet velocity were used to obtain similar time series of the full-scale data. The results show that the fully-developed velocity profiles of the wall jet cohere with those of the three theoretical models and the classical wall jet experiment. When the translational velocity is 15% of the impinging jet velocity,the maximum horizontal wind speed increased by 15.8% compared to that of the stationary impinging jet,while when the velocity of co-flow is 19.2% of the wall jet velocity,the maximum horizontal wind speed increased by 16.9% compared to that of the wall jet without co-flow. The stationary downburst can be appropriately simulated using the wall jet model without co-flow,while the travelling downburst can be effectively simulated using the wall jet model with co flow. The results from large eddy simulation (LES) and data obtained from Andrews AFB downburst are in good agreement. The unsteady characteristics of downburst outflow can be perfectly reproduced by the time functions of the velocity inlet
SDH网规划仿真系统业务部署模块的设计与实现
The Design and Implementation of Service Deployment Module of SDH Network Planning Simulation System
 [PDF]

, 李莉
Smart Grid (SG) , 2014, DOI: 10.12677/SG.2014.43014
Abstract:

本文研究的重点是电力通信网业务部署模块的设计与实现。业务部署是SDH网络规划的一个重要环节,SDH网络的设备以及链路搭建的主要目的正是为了承载业务。本文首先介绍了电力通信网规划这一概念提出的背景、电力通信网规划仿真系统的技术基础、电力通信网规划仿真系统的功能分析。其次,对仿真系统的业务部署模块进行了需求分析和概要设计。再次,本文针对电力通信网规划仿真系统业务部署模块进行了详细设计,提出了配置管理仿真系统的实现架构,并阐述了各子模块之间的关系。最后基于Eclipse和FLEX开发工具实现了该仿真模块。
This research focuses on the design and implementation of service deployment module in grid power communication network. Service deployment is an important part of SDH network planning, as the main purpose of device and link deployment in SDH network is to undertake the businesses. This paper introduces the background of the power communication network planning, the technology of power communication network planning simulation, and the function analysis of the simulation system. Then this paper makes the requirement analysis and preliminary design of the service deployment module of the simulation system, and shows the detailed design of the deployment module with the architecture of the configuration and management simulation system, explaining the relationship between the various sub-modules. Finally, this paper shows the implementation of this simulation module based on Eclipse and FLEX.

液流式微型全化学分析系统

重庆大学学报 , 2002, DOI: 10.11835/j.issn.1000-582X.2002.01.037
Abstract: 介绍了分析化学的一个新兴领域微型全化学分析系统(μ-TAS)的设计思想和相应微机械制作技术,针对液流微分析体系探讨了微型化过程和参数及其相关理论分析,列出了目前液流化微型化体系在生化分析,环境监测等领域中的应用,最后简介了μ-TAS的发展前景及产业化方向。
咨询机构在产业集群创新系统中的地位和作用

图书情报工作 , 2005,
Abstract: ?探讨咨询机构在产业集群创新系统中的地位和作用。提出咨询机构在产业集群创新系统中位于可控支持网络层,是公共服务机构的一分子的观点;认为通过各种专业咨询服务、员工培训和人才流动等途径可促进产业集群技术学习的顺利进行,并进而促进产业集群创新系统的形成和完善。
关于网络咨询业需要商榷的几个问题

图书情报工作 , 2003,
Abstract: ?在回顾网络咨询业产生的时代背景和理论基点的基础上,探讨“网络咨询业”一词中“网络咨询”的内涵、网络咨询业的服务对象、网络咨询业的服务内容这3个需要商榷的基本概念,并尝试着为网络咨询业下一个定义。
超超临界660mw机组给水泵汽轮机运行特点及故障分析

热力发电 , 2011,
Abstract: 华能上海石洞口第二电厂超超临界660mw机组给水泵汽轮机(小机)为nd(z)84/79/07型变转速凝汽式汽轮机,采用弹簧基座,可满足主机在各种工况运行时对给水的要求。总结了小机的特点及运行中存在的问题,并对小机的优化运行提出了建议。
超超临界660mw机组汽轮机的特点与性能

热力发电 , 2011,
Abstract: 介绍了华能上海石洞口第二电厂超超临界660mw机组汽轮机的特点和性能优势,并对发电机转子、轴封蒸汽温度、补汽阀、高压缸效率等存在的问题提出了优化建议。
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