折皱型筛网填料在气-液鼓泡塔中流体力学特性的研究

本文研究了鼓泡塔中装置折皱型筛网填料后的气含率与液相返混。实验在直径 ８．５ｃｍ，高１２０ｃｍ的玻璃塔内进行，填料由４，５，７目金属筛网压制而成．实验结 果看到折皱型筛网填料对两相鼓泡流起着梳整的作用。操作中气泡尺寸受到网孔尺寸 的限制，并使得气液分散均一，气含率有所增加．本文还用不规整脉冲示踪法测定了 液相轴向混合分散系数，探讨了气速、液速、填料尺寸对它的影响，总的结果表明， 液相轴向混合分散系数要比无填料鼓泡塔的数值小一个数量级。     

浅层气液两相鼓泡塔非线性混沌特征

研究了内径383mm、高径比（H／D）为1～3、多管布气的浅层气液两相鼓泡塔内的压力波动信息的非线性混沌特性。通过差值准相空间构造吸引子法确定重构相空间的时间延迟。探讨了不同高径比、不同轴向位置下表观气速对非线性混沌特性的影响。鼓泡塔不同区域的奇怪吸引子结果表明：对于HD≤3的气相多管分布的浅层鼓泡塔,沿轴向可区分为下部气泡分裂区、中部分裂与凝并过渡区和上部分裂凝并平衡区。鼓泡塔中存在小尺度的气泡运动、中尺度的气泡涡旋运动和大尺度的涡旋流动。其混沌特征参数具有多值性。高频小尺度的气泡破碎凝并的复杂非线性动力学运动特征。需要3～4个参数加以描述;鼓泡塔上部气泡运动的规则性加强。动力学描述所需参数减少至2～3个;Kolmogorov关联熵在uk=0．15～0．25m/s内存在极小值。表观气速可以得到优化。     

以鲍尔环为内构件的鼓泡塔反应器的流体力学性能

对二甲苯氧化合成对苯二甲酸常用鼓泡塔作为气液反应器,以填料为内构件可以强化鼓泡塔反应器的气液接触状况,从而提高反应速率。以金属鲍尔环为内构件,考察鼓泡塔反应器的气液接触状况,采用高速摄像技术对气泡群进行图像分析,同时利用体积膨胀法测定气含率,研究不同型号鲍尔环作用下的气含率、气泡尺寸和粒径分布。结果表明,Φ25鲍尔环对气泡的切割效果最好,气泡的尺寸分布较为集中,主要处于3.00～6.00 mm之间,Sauter平均直径随气速增大而增大,并在高气速下趋于平缓;鼓泡塔反应器的气含率随气速增大而增大,且鲍尔环尺寸越小气含率越大。利用实验数据进行非线性回归,得到在实验气速范围内气含率与气泡Sauter平均直径、比表面积的关联式,计算值与实验结果较为吻合。     

浅层气液两相鼓泡塔非线性混沌牲

研究了内径383 mm、高径比(H/D)为1～3、多管布气的浅层气液两相鼓泡塔内的压力波动信息的非线性混沌特性.通过差值准相空间构造吸引子法确定重构相空间的时间延迟.探讨了不同高径比、不同轴向位置下表观气速对非线性混沌特性的影响.鼓泡塔不同区域的奇怪吸引子结果表明:对于H/D≤3的气相多管分布的浅层鼓泡塔,沿轴向可区分为下部气泡分裂区、中部分裂与凝并过渡区和上部分裂凝并平衡区.鼓泡塔中存在小尺度的气泡运动、中尺度的气泡涡旋运动和大尺度的涡旋流动,其混沌特征参数具有多值性.高频小尺度的气泡破碎凝并的复杂非线性动力学运动特征,需要3～4个参数加以描述;鼓泡塔上部气泡运动的规则性加强,动力学描述所需参数减少至2～3个;Kolmogorov关联熵在ug＝0.15～0.25 m/s内存在极小值, 表观气速可以得到优化.     

自适应网格在鼓泡塔内气液两相流仿真的应用及实验验证

研究了一种鼓泡塔反应器,气体从鼓泡塔边壁注入与鼓泡塔内的液相发生反应。为准确展现鼓泡塔内气泡形状和分析近壁效应,运用试验和仿真两种方法深入研究鼓泡塔内气液两相流动。试验结果验证了多相流仿真模型的可行性;同时证实了自适应网格的优越性。相比于多面体网格、裁剪网格、结构网格,自适应网格通过自动加密气泡周围的网格提高仿真精度,改善气液两相流中气泡形状(橄榄状),细化气泡直径范围(1~40 mm),准确地捕捉近壁效应区间(6 cm)。可以为同类别研究提供参考依据。     

冰山运输费用分析

修改了Ｃｒｏｓｓ和Ｍｏｓｃａｒｄｉｎｉ建立的从南极用拖船运送冰山到波斯湾的数学模型，使最低费用由原来的０．０５５￡／ｍ３降到０．００４￡／ｍ３     

固阀塔板上密集鼓泡区气泡的运动行为特征

利用双头电导探针测定了固阀塔板上密集鼓泡区气泡的运动速度,考察了密集鼓泡区不同轴向高度的气泡速度分布规律及其分形特征,分析了塔板上密集鼓泡区的气泡运动行为。研究结果表明:不同轴向高度处气泡速度沿同方向的分布具有相似性,近塔中心区域气泡速度变化平缓,呈弱双峰分布;塔板上气泡速度分布具有分形特征,分形维数为1.04~1.25,且随轴向高度的增加均先减小后增大;深层鼓泡区内气泡速度分布的分形维数可以较好地表征气泡运动的湍动强度,两者之间存在线性关系,气泡流湍动强度及分形维数与泡沫层高度间存在指数函数关系。     

三相鼓泡塔反应器液体流速分布的实验研究

采用示踪剂电子电极法对气-液-固三相鼓泡塔局部液体流速的测试结果表明,塔中心处的局部液速最大,近塔壁处最小,随表观气速增大,初始流体流动处于由均匀流型向过渡流型的转变;当表观气速继续增大,平均液速则明显增加,轴向液速的径向分布呈线性关系,表明流体的流动进入非均匀流型;三种不同结构的气体分布器对反应器中心线处轴向流速影响的实验表明,环状气体分布器的反应器底部存在一个狭小的回流区。     

CFD优化大型浅层鼓泡塔管式气体分布器结构

分布器结构影响大型浅层鼓泡塔反应器性能,采用CFD模拟研究了5种四管气体分布器,各分布器的通气管均匀布置在不同的分布环上（0.3/0.4/0.5/0.6/0.7＊DT）,模拟采用了双流体方法和多气泡簇MUSIG模型。文中较全面的考察了高表观气速下（Ug=0.1m/s）管式分布器分布环直径对反应器流型、相含率、液速、湍b流、气泡大小以及混合时间的影响;模拟结果表明整体气含率和混合时间均随环径比先增大后减小,气含率的最佳环径比在0.4左右,而混合时间最大值出现在0.5d/DT附近,当环径比小于时0.5,鼓泡塔内为单循环流动,大于此值,鼓泡塔内将形成双循环流动,不利于混合。     

CFD研究短导流筒对鼓泡塔流体动力学的影响

采用双流体模型及k-ε湍流模型模拟研究了短导流筒内构件对鼓泡塔流体力学性能的影响。共模拟了4种鼓泡塔,即简单鼓泡塔和3种安装有导流筒的鼓泡塔,塔径D均为190 mm,导流筒离底距离分别为0.5D、1.0D、1.5D,导流筒直径为0.7D,长度为1.0D。结果表明,简单鼓泡塔模拟结果与文献实验值吻合较好;安装导流筒后,导流筒下游气含率和轴向液相速度径向分布更为均匀,并且在不降低整体气含率的情况下,显著提高了鼓泡塔底部的液相轴向脉动速度,将有利于三相鼓泡塔内的固体颗粒悬浮。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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