COREX竖炉内部结构对物料运动影响的物理模拟

建立COREX竖炉三维半周冷态模型,物理模拟炉内结构对物料运动的影响,考察不同操作条件下AGD梁及导流锥对物料运动流型的改变。模拟结果显示:无AGD梁COREX竖炉内物料运动流型呈现‘一’→‘U’→‘W’的演变过程,而AGD竖炉则在围管区域经历波浪型及初始‘W’流型,AGD梁影响围管区域物料的均匀下降。非工况单侧停机条件下,AGD竖炉内物料活跃区面积减小,死料区面积增大,易引起炉内无滑移物料的接触挤压时间变长,导致炉料的黏结结块,造成炉况的进一步恶化。非对称排料(7.29~14.6 r/min)时,无AGD竖炉上方物料均匀下降,而AGD竖炉内一侧物料运动行为相对独立于另一侧。竖炉下部导流锥有利于促进竖炉上部物料均匀下降和竖炉下部的顺滑排料。     

油页岩气体热载体干馏炉炉内流动特性

对一台1 t/d油页岩气体热载体干馏炉炉内流场特性进行了数值模拟。基于计算流体力学的理论方法,采用以Ergun方程基础上建立的多孔介质模型、湍流模型进行研究。将模拟结果与前人研究成果进行对比分析,结果表明,采用添加阻力源项的多孔介质模型、RNG k-ε湍流模型等封闭模型能够较好的模拟炉内流场分布特性,并在原有结构基础上进行优化,增设同轴及偏心轴撞击流布气方式。在本文提出的布气方式下,无论采用同轴亦或是偏心轴布置,均能形成良好的速度场及压力场,提高干馏段气体混合程度,拓宽布气范围,增加气体与固体颗粒之间的接触面积和时间,强化换热进而确保干馏效果。模拟结果可为开发大容量气体热载体干馏炉及优化设计提供理论依据。     

油页岩固定床干馏过程三维数值模拟

主要研究了固定床内油页岩干馏过程的三维数值模拟。通过对固定床内气固相间传热传质过程的分析,建立了完整的气固两相传热传质模型,并采用多孔介质模型与流动模型相结合,将干馏过程中水分析出和干馏油气的析出过程通过用户自定义接口添加到模拟过程中。针对实际工况进行了模拟研究并与实验结果进行比对,吻合程度较好。此外,分别从进气速度和进气温度等方面进行对比分析,研究结果表明当进气速度提高0.5倍时,干馏进程加快1 600 s。当进气速度降低0.5倍时,干馏进程延缓4 200 s,换热效率明显降低。进气温度提高100℃,干馏进程加快600 s,油页岩中干酪根热解过程前期水分最大蒸发速率提高约11.4%。当进气温度降低100℃时,干馏进程延缓1 300 s,干酪根热解过程前期水分最大蒸发速率降低约24.7%。在气体热载体和传质过程的共同作用下,靠近进气位置的底部颗粒与周围环境气体中水蒸气及干馏油气之间的浓度梯度小于上部颗粒,这也是固定床内上部颗粒干馏进程较慢的一个重要原因。     

Texaco气流床煤气化炉内气固两相流动的数值模拟

应用Eulerian-Lagrangian方法对国内某工厂实际运行的Texaco气流床煤气化炉内气固两相流动进行了模拟.采用Realizable k-ε模型计算炉内复杂气体湍流运动,应用颗粒轨道模型追踪煤粉颗粒在湍流气流中的运动轨迹.通过数值计算取得了炉内气相速度矢量、颗粒运动轨迹、颗粒碰撞壁面并沉积于壁面的沉积通量和颗粒在炉内的停留时间分布.揭示了该气化炉的气固两相流动特性,并分析了运行工况对壁面沉积通量分布的影响规律.结果表明:气化炉内的气体流场存在回流,回流延长了颗粒在气化炉内的停留时间,颗粒沉积通量最大的位置为筒体段下部和锥体段上部; 绝大部分颗粒在气化炉内的停留时间在5 s以内,气体流量降低时颗粒在炉内的停留时间减少.     

油页岩气体热载体干馏炉内布气均匀性的冷态试验

为研发新型油页岩气体热载体干馏炉布气方式,自主设计并搭建了干馏炉的干馏段的冷态试验台。对不同料层厚度和不同布气方式下的炉内速度分布和料层阻力进行了试验研究。试验结果表明:炉内流速分布情况为中心流速最小,边壁处流速最大;且中心向边壁流速先增大后减小再增大。与进气管方向相同的布气管周边的速度最大,其次是四周与进气方向垂直和成45°夹角的布气管,与进气管方向相反的布气管周边速度最小;满料时四层布气比两层布气时速度分布更加均匀。炉内中心处料层阻力最小,边壁处阻力最大;且沿半径方向先增大后减小再增大。布气管顺序排列比交叉排列时炉内料层阻力大。     

适合小颗粒油页岩的新型热解技术

正小颗粒油页岩颗粒与作为热载体的高温页岩灰在混合器中混合,并进入主反应器。经过固-固传热,油页岩温度升高并发生干馏,生成热解油气。传统的反应器中并无任何构件,热解油气会与从混合器落下的颗粒发生对流,使得热解油气中的含尘量很高。在反应器物料层内加装带有孔道的特定结构部件(内构件),热解油气可通过导气孔进入内构件并被油气回收系统收集起来,经冷凝分     

基于“磨粒磨损”原理颗粒几何参数对制动块摩擦和磨损实验研究

为研究摩擦界面三体颗粒几何参数对制动块摩擦特性的影响及摩擦磨损的机理,文章利用摩擦磨损试验平台,以氧化铝颗粒几何参数为变量,对摩擦界面摩擦力学参数进行实时测量,研究不同几何参数在长时间制动过程中对制动块摩擦特性和磨损率的影响,利用电镜分析研究摩擦磨损机理。研究发现：在连续较长摩擦时间条件下,粗糙峰遭到破坏,“磨合稳定恶化磨损”过程不断重复;较小颗粒的加入会加速次级平台的产生,摩擦性能有所增加;随着颗粒几何参数的增大,载荷将较大颗粒限制在摩擦界面或嵌入制动摩擦块内,增加了粗糙峰,摩擦性能会进一步增大;超过100μm,颗粒不受载荷限制,破坏接触平台和摩擦膜,加速磨损,摩擦性能开始减弱;颗粒的加入可以加速次级平台的成长,稳定的氧化膜才是形成稳定摩擦的关键因素,随着颗粒几何参数的增加磨损量会逐渐增加。     

球团竖炉内气体流动的数值模拟

根据气固填料床动力学,建立了“导风墙-烘干床式”球团竖炉内气体流动的数学模型·运用自编程序数值求解炉内速度场,研究炉内气体流动的基本规律,探讨竖炉操作参数对炉内气体流动的影响规律·结果表明:焙烧风和冷却风在进口处呈放射状,之后斜向上或斜向下分别流入焙烧-预热带和导风墙内;整个均热带内气流较为薄弱;炉内存在三种气流分流的可能,流入风量比是决定气流分流的最主要因素,其中,流入风量比增加,焙烧风下行趋势增大,而冷却风上行趋势减小;临界流入风量比主要取决于结构参数和料层情况     

气液两相流多喷嘴分流取样计量研究

提出一种具有4个分流喷嘴的新型取样器结构,根据分流比和取样流体气、液流量确定主管路气液相流量。为保证取样流体的代表性,采用"流型调整"与"阻力控制"两种方法抑制相分离的发生。建立气液两相流数值模型,模拟气液两相流在取样器中的流动特性。在气液两相流试验环道上开展试验测试,流型包括波浪流、段塞流及环状流。结果表明:在试验范围内气、液相分流系数接近理论值0.25,其主要取决于分流喷嘴的数目,不受流型、气液流速等参数波动的影响,流量测量误差小于±6.0%。该取样计量装置具有体积小、精度高、维护费用低的优点,可代替传统计量分离器,实现气液流量的实时测量。     

COREX竖炉物料运动流型及瞬态特性的离散元模拟

基于离散单元数值计算方法,建立COREX竖炉内物料颗粒尺度运动行为的数学模型,研究炉内物料运动流型及其瞬态特性,特别是颗粒的瞬态速度和瞬态应力分布.模拟结果表明:COREX竖炉内存在三种类型的流动区域:活塞流区、准停滞区以及沟流区.炉内颗粒的瞬态速度分布表明炉内存在两种类型的速度波:装料过程引发的向下传播的速度波和底部排料引发的向上传播的速度波.COREX竖炉内颗粒法向应力随时间的变化较小,竖炉底部导流锥顶部存在较强的应力区,而无导流锥竖炉底部中心存在较强应力区,沟流区的应力较弱.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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