通信机房气流组织特性研究与空调冷量调配方案设计

为降低通信机房空调能耗,减少机房局部热岛效应,通过运用CFD（计算流体动力学）方法对通信机房空调气流组织特性进行了研究,在建立机房空调气流组织特性的数学物理方程的基础上,对其进行了数值求解,全面分析了送（回）风口、通信设备周边及通信机房多个断面的气流速度场与温度场,并对样本机房进行了实验测试与验证分析.实验验证表明数值求解结果与实测值基本一致,可见所建立的模型是正确的,数值求解的结果是可信的.最后,基于通信机房空调气流组织特性的数值求解结果以及样本机房的实验测试研究,对机房送回风的调配方案进行设计,从而优化机房内设备运行环境,减少机房冷量浪费,挖掘节能潜力.     

空调房间内非等温送风气流组织的数值研究

本文采用非稳态k-ε模型对空调房间内侧送侧回的气流组织进行了数值模拟,分别获得等温、制热、制冷三种工况下的速度分布图,比较了速度分布的异同,分析了浮升力对气流组织的影响。计算结果可用于指导空调房间气流组织的设计工作。     

会议室内飞沫气溶胶分布特征的数值模拟

目的分析会议室内不同气流组织对人持续说话产生的飞沫气溶胶运动轨迹的影响,模拟飞沫气溶胶在会议室内的分布特征,确定最佳的气流组织方式.方法采用CFD数值模拟方法,选择RNG k-ε湍流模型计算空调房间的温度场和速度场,分析飞沫气溶胶颗粒的受力情况,采用拉格朗日法建立飞沫气溶胶颗粒运动的数学模型,模拟空调房间会议室内同侧上送上回、同侧上送下回、对侧上送下回3种混合通风和置换通风对飞沫气溶胶的运动轨迹.结果飞沫气溶胶运动轨迹显示飞沫气溶胶在置换通风停留时间和运动距离最短.3种混合通风气流组织相比,同侧上送上回的气流组织中飞沫气溶胶运动时间112 s和运动路程11.1 m最短,同侧上送下回次之,对侧上送下回最长.结论 3种混合通风中,同侧上送上回更容易避免飞沫气溶胶在室内传播,是最佳的混合通风气流组织方式.置换通风相比于混合通风更易减小人员之间受感染的可能性,是最佳的气流组织方式.     

基于多节点模型的大空间垂直温度分布研究

针对大空间下送中回气流组织室内热环境,以室内空气为研究对象,通过在垂直方向上分层建立能量平衡方程与质量平衡方程,建立多节点温度求解模型,并利用大空间缩尺模型稳态环境实验予以验证,通过4个工况验证结果可知,各空气温度的理论计算值与实验值的最大绝对误差不超过3%,平均误差为1.4%.     

YW25G型空调硬卧列车车厢内气流数值计算

以YW25G型空调硬卧列车车厢为研究对象建立物理模型. 物理模型中考虑了车厢内各障碍物, 包括边桌、行李架、床铺、折座等的影响, 采用K-ε湍流模型对车厢内三维湍流流动和传热进行数值模拟, 研究车厢内流场及温度场的分布变化规律. 研究结果表明: 下铺区域的气流组织及温度分布较好, 其次是中铺, 上铺区域的气流组织及温度分布较差;距车门越近, 气流组织越好, 车厢中部区域的气流组织最差;床铺区域的空气温度较走廊区域的空气温度低.     

数据中心热环境数值模拟影响因素分析

为得到准确的数据中心气流组织模拟结果,采用专用模拟软件,对比分析考虑和忽略高架地板漏风、地板下线缆、空调供回水管和照明设备等因素对模拟结果的影响.结果表明,忽略上述因素时,模拟机房内整体的温度较低,热点机柜较少;考虑上述因素时,机房的整体温度高出1℃~3℃,其中地板下的线缆和空调供回水管对地板下的流场影响较大,尤其是架空地板层高较低,且线缆布置在地板下的情况.因此,在研究数据中心的气流组织时,是否忽略以上因素,应根据实际情况确定.     

高大空间风口位置高度对供暖效果的影响

分层气流组织可以改善高大空间热风供暖的节能性和热舒适效果.为估计这种气流方式对室内热环境的改善效果,在利用实验验证数值计算方法的基础上,通过数值模拟探讨了大空间送、回风口高度对室内热环境的影响.研究结果表明:送风口位置位于较低的位置时,热风供暖的能量在这种房间下部区域的利用率较高;当送风口位置增加到8.5m且上回风时,即使以高能耗为代价,室内热环境也难以满足人体热舒适要求.此外,根据模拟结果对不同情况下的供暖能量利用系数做了分析,并对改善大空间冬季热风供暖的节能和热舒适性给出了一些建议.     

地板送风数据机房空调系统气流组织的优化

针对地板送风数据机房内数据设备发热量大、占地面积小、集成度高等特点,提出一种通过改善机房及机柜内部气流组织与温度分布的方法.首先,利用CFD软件Airpak对地板送风机房空调系统进行数值建模,并利用盒形图对影响系统气流组织的因素进行优化分析,得出系统具有最优温度分布情况时的参数值.然后,通过实验对优化后的模型进行验证,并将封闭冷通道的方法应用到该优化后的系统中,进一步考察优化后系统的可扩展性.研究结果表明,该优化方法不仅能够改善冷通道开放的地板送风机房空调系统的温度分布及气流组织,并且优化系统在冷通道封闭后,系统的温度分布还会得到进一步的改善.     

普通病房飞沫污染物传播特性与评价

空调病房良好的气流组织能快速地排除室内病人产生的飞沫污染物,从而减小医护及陪护等健康人员的感染风险.通过文献分析给出人体呼吸活动产生飞沫的粒径、数目、速度和温度等基础数据,利用Fluent软件建立普通病房物理模型与飞沫污染物蒸发扩散模型,借助Fluent软件的开放接口UDF(用户自定义函数),编写描述病人呼吸与咳嗽产生飞沫的非稳态速度分布的UDF程序作为速度输入条件,模拟了普通病房在上送上回、贴附射流和上送下回3种典型的气流组织形式下,人体飞沫污染物的传播特性.模拟结果发现,3种气流组织病房中,粒径为0.1～3μm的飞沫在病人与健康人员呼吸区域个数浓度均最大,上送下回气流组织形式病房内健康人员呼气区域的飞沫个数浓度比上送上回低40％,比贴附射流组织形式低近70％,且通风效率更高、排除飞沫污染物的效果更好,建议普通病房采用上送下回气流组织形式以降低室内人员的交叉感染风险.     

负压隔离病房空气环境控制研究

对负压隔离病房的空气环境以及病房内污染气体扩散机理进行了研究,利用数值模拟方法分析病房内流场、压力场、温度场和污染气体浓度场的整体分布,提出两个气流组织改进方案,优化病房污染气体扩散控制效果。模拟结果表明,三种通风方案均能保证不同区域之间满足大于5 Pa的压力梯度,病房温度分布满足夏季室内空调温度设计要求,采用顶送风/病床上方布置排风口的气流组织,能保证病房达到病患舒适度,并且能有效控制污染气体扩散。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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