吸收器降膜和滴状吸收过程数值模拟分析

针对以溴化锂水溶液为工质的水平管吸收器,考虑润湿比、变膜厚和横向对流作用,建立了描述管表面的降膜流动和管间滴状吸收传热传质耦合过程的数学模型,采用涡量流函数法进行数学模型求解。根据数值计算结果,分析了溶液温度、浓度和吸收速率沿管排不同位置和水平管管间的变化,以及溶液喷淋密度和进口浓度对吸收器整体传热传质性能的影响。结果表明,提高喷淋密度可以改善吸收器传热性能,提高溶液进口浓度可改善传质性能,滴状吸收过程约占总吸收量的20%。与实验数据的对比说明建立的数学模型是合理的。     

吸收器降膜和滴状吸收过程数值模拟分析

针对以溴化锂水溶液为工质的水平管吸收器，考虑润湿比、变膜厚和横向对流作用，建立了描述管表面的降膜流动和管间滴状吸收传热传质耦合过程的数学模型，采用涡量一流函数法进行数学模型求解。根据数值计算结果，分析了溶液温度、浓度和吸收速率沿管排不同位置和水平管管问的变化，以及溶液喷淋密度和进口浓度对吸收器整体传热传质性能的影响。结果表明，提高喷淋密度可以改善吸收器传热性能，提高溶液进口浓度可改善传质性能，滴状吸收过程约占总吸收量的20％。与实验数据的对比说明建立的数学模型是合理的。     

溴化锂溶液绝热吸收水蒸气的传质强化研究

依据双膜理论假设,建立了规整填料绝热吸收器数学模型,通过对连续性方程和动量方程简化得出速度关系式,从而保证程序计算结果收敛和减少计算时间,依据计算结果分析了喷淋溶液温度、浓度、流量和吸收压力对传质系数影响,并将计算结果和实验结果进行比较.结果表明,增加喷淋溶液流量能显著增大溴化锂溶液绝热吸收过程传质系数;数值计算结果和实验结果吻合较好.     

超重力旋转床转子填料形状对传质系数的影响

以水吸收空气中的丙酮为体系,不锈钢丝网为填料,实验研究了超重力旋转床转子填料形状对体积传质系数的影响。考察了转子形状在不同转速n、气量Vg、液量VL下的吸收效果。研究结果表明:在转速为630 r/min,液量为100 L/h,气量为2 m3/h时,薄转子是厚转子单位体积填料体积传质系数的2.1倍;在转速为630 r/min液量为100 L/h,气量为2.5 m3/h时,薄转子是厚转子单位体积填料体积传质系数的2.3倍;说明在填料体积相近的情况下,转子填料做成半径大、厚度小的形状,有利于传质过程。     

规整填料绝热吸收器传热传质特性模拟算法

建立降膜绝热吸收传热传质过程数学模型,通过Nusselt模型对数学模型简化获得液膜流动速度方程,利用有限差分法对数学模型进行离散化处理,采用TDMA算法进行算法设计,程序迭代算法采用二分法.数值计算喷淋溶液温度、初始浓度、流量和吸收压力对传质系数影响,模拟计算规整填料绝热吸收器内溶液温度和浓度分布规律,并利用实验数据验证模型合理性.该数学模型为规整填料绝热吸收器优化设计提供理论基础.     

界面湍流下溴化锂水溶液膜流吸收强化的研究

利用降膜吸收试验系统 ,研究了在不同的溶液降膜流动雷诺数 Re下 ,无活性介质和加有3× 1 0 -5质量浓度 2 -乙基己醇的溴化锂水溶液降膜吸收强化过程 .结果表明 ,上述两种情况下 ,降膜吸收随 Re的增加 ,溶液侧平均换热系数和吸收传质系数均增大 ;且在 Re<80下 ,加有 2 -乙基己醇的吸收效果比无活性介质的吸收有明显的增强 ,随 Re进一步增加 ,强化效果逐渐变得不明显 .利用激光全息干涉技术 ,观察了流动液膜吸收过程中膜内溶液温度和质量分数变化引起的干涉条纹变化以及液膜流动的表面状况 .观察到 ,加有活性介质吸收中引起的干涉条纹较无活性介质的分布密 ,条纹要细 ,且液膜表面还出现不规则扰动 .这种扰动是由加入活性介质后吸收中溶液表面张力变化所引起的界面湍流     

超重力旋转床中气液两相流动与传质过程的数值模拟

文中采用基于颗粒轨道模型的欧拉-拉格朗日法对超重力旋转床中的气液两相流动与传质进行了数值模拟研究。在合理简化丝网填料结构和考虑液滴凝并与分散的基础上,分别利用SIMPLE算法和颗粒轨道模型计算了超重力旋转床中的气流场和液滴的运动轨迹,进而计算了液相的传质系数。数值模拟所得的液相传质系数与氮气解吸水中溶解氧实验结果符合良好,表明模型能够用于模拟旋转床中流体力学和分散相内的传质过程。计算分析表明,对超重力旋转床,在一定的转速下,液体和气体流量以及填料内径的变化对体积传质系数有重要影响。     

降膜式发生器的传热传质研究

降膜式发生器在溴化锂吸收式制冷机与热泵中得到了一定的应用,溴化锂降膜式发生器在较小的液液量和较小的温差下获得较高的热流密度和传势传质系数,尤其是当液膜沿着水平管外作降膜流动时,传热传质效果更佳,为此建立了省化锂降膜式发生器溶液发生过程传南的数学模型,该模型考虑了流动、传势与传质同时进行相互耦合的特点,对不同布液方式下的液膜流动初速进行了修正,对模型进行求解,并建立了实验台对降膜式发生器的传热传质进行实验,通过对800多组数据进行回归得出了计算传热与传质的准则关系式。     

θ环填料塔中飞灰对TETA溶液吸收CO_2性能的影响

为了解燃煤烟气中飞灰颗粒对三乙烯四胺(TETA)溶液吸收CO_2性能的影响,采用液相加入飞灰的方式,在自行设计的乱堆不锈钢θ环填料塔内进行了实验研究.考察了飞灰在溶液温度、液气比、填料高度和飞灰浓度等操作条件下对TETA溶液吸收CO_2的效率η和体积总传质系数K_Ga_V的影响规律.结果表明:飞灰的存在降低了TETA溶液吸收CO_2的效率η和体积总传质系数K_Ga_V,且随着飞灰浓度的提高其影响呈增加趋势;随着溶液温度的增加,TETA溶液和TETA-飞灰溶液吸收CO_2的效率η先升高后降低,K_Ga_V则平稳升高;随着液气比的提高,η和K_Ga_V均快速升高;随着填料高度的增加,η和K_Ga_V升高,但K_Ga_V的升高速率较快;随着溶液温度、液气比和填料高度的增加,飞灰对η和K_Ga_V的影响逐渐减弱.     

水平管间溴化锂溶液滴状降膜流动分析

对溴化锂溶液在水平管间的实际液滴流动过程进行了记录分析,以改进目前滴状降膜吸收数值模型中的理想化球形液滴假设.使用高速摄像机,对16 mm管间距下溴化锂溶液滴状流动过程进行了拍摄.采用图像边缘识别技术、样条拟合和二维曲线旋转积分方法,得到了液滴表面积和体积关于时间的变化关系.根据液滴的发展特点,将管间液滴形成划分为悬垂拉伸、不稳定液柱和破裂降落3个阶段,据此提出了不同溶液流量下液滴形成的预测模型.管间液滴表面积和体积发展的预测曲线与实测结果吻合较好.该模型可以在滴状降膜传热传质数值计算中得到应用.     

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