加压湿壁塔内的气传热性质

本文研究了加压条件下空气水系统在湿壁塔内同向流动动时传递行为。分析中考虑了界面处气相混和物非理想行为及剪切应所略传质对气体运动影响。提出了计算加压条件下气侧局部传热传质系数关系式,燕对两相加压下传递行为进行系统地分析。分析结果表明,采用常压计算方法进行加压传热传质计算,将产生较大的偏差。     

PTA氧化反应冷凝器传热传质行为分析

针对PTA氧化反应中冷凝器内的醋酸、水和氮气混合蒸气冷凝过程,考虑冷凝过程中惰性气体和气相醋酸-水缔合效应,分析了各级换热器内传热传质行为以及传递对换热器设计的影响。计算结果表明,高溶剂浓度下的冷凝过程是气相在近似相平衡状态进行,可以忽略气相中传递限制,而随着气相中溶剂含量的减少,组分在换热器进口段的传热传质效果对换热面积设计影响尤其明显。     

微通道内传递对液液分散过程的影响规律

在同轴环管微通道中,采用水/正辛醇形成两相体系,利用硫酸向水中传质并释放热量以实现伴随传质传热的微分散过程,研究了两相流速、硫酸浓度对两相流型和液滴大小的影响规律。结果发现,传递会引发O/W/O新流型的产生和流型分布区域变化。探讨了传递强度对于分散液滴尺寸的影响,通过计算液滴脱落时的动态界面张力,分析了传质和传热对于液液微分散影响的大小。     

膜过程中热质耦合传递分析

研究了透过致密无孔膜的传热传质过程,考察了传热传质的相互作用,建立了膜过程中热质耦合传递的数学模型,并以湿空气透过薄膜分离过程为例,分析了温差及浓度差的变化对传热传质过程的影响,发现温差及浓度差的变化会引起热阻及湿阻的变化,从而进一步影响热流量和传质通量,所以对传热传质过程有加成作用。     

循环流态化：（Ⅴ）传递规律

在循环流态化气、固传递规律研究中,传热规律的研究非常活跃,而传质规律的研究十分薄弱。本文着重阐述了循环流化床内床层与表面间的传热规律,综合分析了操作条件、颗粒物性以及传热表面几何尺寸等因素对传热系数的影响,同时对传热机理及其模型进行了讨论。     

生物质热解气喷雾冷凝的传热传质特性

生物质热解气的快速冷凝是影响生物油品质和出油率的关键因素之一。喷雾冷凝是实现快速冷凝的有效方法。文中以生物质热解气的关键组分所形成的多组分体系为研究对象,采用多组分体系传热传质经典的膜模型,使用Maxwell-Stefan方程描述其质量传递,结合气液相际传质的特点,进行了喷雾冷凝过程中的传热传质耦合计算。通过计算获得了液滴直径、液滴平均温度以及混合气体平均温度的变化规律,并探讨了初始流速、喷雾液滴直径和气液质量流量比对热解气冷凝过程的影响。     

动量,热量及质量湍流传递原理的研究进展

本文简要介绍了二维湍流传递问题如平直园管中单相流体湍流传热及降膜对固体壁传热等的数值解及分析解概况。也讨论了流体与固体壁界面和流体与流体界面处湍流传递现象的差别及其对传热与传质准数关联式推导的影响。半理论方法被用于三维湍流传递过程如搅拌槽和鼓泡塔的分析,用这些半理论分析方法可以推导出传热或传质的初步关联式,这将有助于通过较少实验工作来取得正确的传递关联式。理论及半理论分析均将帮助人们更深入了解设备中的传递过程机理,从而指导人们发现改进这些传递过程的途径。     

微藻培养光生物反应器内传递现象的研究进展

微藻规模化培养过程中光生物反应器内传递现象是影响微藻的生长及产量的重要因素。本文重点综述了光生物反应器内传递现象（光传递、传热、传质和传动量传递）及其数学模型研究进展,分析了光生物反应器结构和尺寸对光传递和传质的影响,总结影响各传递现象的重要参数,如光吸收系数、体积传质系数等,为高效光生物反应器的设计、优化及放大提供了参考依据。     

竖直管外降膜吸收传热传质过程强化的研究

对LiBr溶液在光滑管和四种换热强化管竖直管外降膜吸收过程进行了实验研究，得到了实验条件下的最佳管型，分析了非绝热吸收过程中传热传质相互作用，相互影响的关系，建立了竖直管外降膜吸收热－质传递过程的数学模型，并对该过程进行了数值计算，模型计算值与实验结果的比较证明该模型具有较好的适用性。     

析湿工况下平直开缝翅片传热传质特性的数值研究

针对现有冷凝模型计算中未考虑对流传质对传质通量的影响,利用Fluent软件中的UDF建立了新的对流冷凝传热模型和基于场协同理论的传热传质特性分析方法。使用新的冷凝模型和分析方法对除湿条件下,入口参数、翅片结构、开缝位置对平直开缝翅片换热器湿空气侧的流动、传热和传质特性的影响进行了研究。结果表明：考虑对流传质的冷凝模型准确度得到提升;传热量、冷凝量随翅片表面开缝高度的增加先减小后增加;上游开缝翅片管的传热量、冷凝量均低于下游开缝翅片管,利用建立的分析方法发现,相同边界条件下,下游开缝翅片的传热场协同角α_m、传质场协同角β_m均小于上游开缝翅片,表明下游开缝翅片的速度场、温度梯度场和浓度梯度场的协同性更优,传热传质能力更强。     

Numerical Simulation of the Solute‐Induced Marangoni Effect with the Semi‐Lagrangian Advection Scheme

The level set method is combined with the concentration transformation method to solve the interphase mass transfer process. However, the artificial diffusion generated in the mass transfer convection term across the interface is inevitable, especially when large shape deformation is encountered at high Reynolds numbers. A semi‐Lagrangian advection scheme is introduced to overcome this disadvantage. The methyl isobutyl ketone (MIBK)‐acetic acid‐water system is adopted to study the unsteady mass transport process accompanied with the Marangoni effect of a single deformable drop ascending in the infinite continuous phase. The predicted overall mass transfer coefficients agree with experimental data very well. The configuration of Marangoni convection is revealed and its effect on the interphase mass transfer process is investigated.     

Experimental investigation and numerical simulation of Marangoni effect induced by mass transfer during drop formation

Marangoni effect induced by interphase mass transfer plays an important role in liquid–liquid extraction and reaction processes. The interaction of Marangoni effect and interphase mass transfer during drop formation at different injection rates and different initial solute concentrations was investigated by experimental and numerical simulation. The extraction fraction was measured and the corresponding correlation was proposed. The level‐set method coupled with mass‐transfer equation is for the first time used to simulate the mass‐transfer induced Marangoni effect during drop formation. The simulated drop volume, shape, and extraction fraction are in good accordance with experimental data. Through the numerical simulation, it is found that the mass transfer in the first mass‐transfer period is the most efficient during drop formation when Marangoni convection occurs. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4424–4439, 2013     

Analysis of Fluidized Bed Drying Kinetics on the Basis of Interphase Mass Transfer Coefficient

A particular way to define fluidized bed drying kinetics on the basis of interphase mass transfer coefficient and the conception of general kinetic curve has been described. The presented method, which allows for minimization of laboratory tests, has been checked experimentally. The method for calculating of mass transfer interphase coefficient in the constant rate period of fluidized bed drying based on Kunii and Levenspiel bubbling bed model is shown.     

Analysis of Fluidized Bed Drying Kinetics on the Basis of Interphase Mass Transfer Coefficient

A particular way to define fluidized bed drying kinetics on the basis of interphase mass transfer coefficient and the conception of general kinetic curve has been described. The presented method, which allows for minimization of laboratory tests, has been checked experimentally. The method for calculating of mass transfer interphase coefficient in the constant rate period of fluidized bed drying based on Kunii and Levenspiel bubbling bed model is shown.     

Separation of Toluene-Trichlorotrinitrobenzene Mixture with CO2 at Elevated Pressures

Abstract

A flow apparatus was used to study the separation of toluene from a liquid mixture containing mainly toluene and TCTNB (trichlorotrinitrobenzene) with CO₂ at elevated pressures. Experimental results indicated that toluene of 100% purity could be obtained when the operating pressures were below the critical pressure of the CO₂-toluene mixture. The most appropriate operating conditions were found to be at a temperature of 311 K and at a pressure of 61.2 atm. Because the solubility of toluene in CO₂ for the system CO₂-toluene-TCTNB was found to be close to that for the binary system CO₂-toluene, the data for the latter system could be used to model the present extraction operation. The effects of several packings, including glass beads of different sizes and structure packing, on mass transfer rate were also measured in this work. The data indicated that the interphase mass transfer resistances played an important role during the extraction.     

Gas-Liquid Mass Transfer Characteristics in a Gas-Liquid-Solid Bubble Column under Elevated Pressure and Temperature

abstract The volumetric mass transfer coefficient kLa of gases (H2, CO, CO2) and mass transfer coefficient kL on liquid par-affin side were studied using the dynamic absorption method in slurry bubble ...     

Regeneration of Activated Carbon Loaded with Toluene by Supercritical Carbon Dioxide

Abstract

Activated carbon loaded with toluene was regenerated by supercritical carbon dioxide. The adsorptive capacities after several regeneration cycles were still close to that of virgin carbon and remained stable. The effects of temperature, pressure, and flow rate on regeneration efficiency were studied. It was found that the operations at higher pressures were more favorable for regeneration, but the optimal operating temperature depended on pressure. The interphase mass transfer resistance was insignificant during regeneration. A one-parameter mathematic model assuming linear desorption kinetics is proposed which agrees well with the experimental data. The adsorption rates of activated carbon regenerated by the supercritical regeneration method and the steam regeneration method are compared in this study. It was found that the supercritical regeneration method is superior to the steam regeneration method.     

The Effect of Bed Temperature on Mass Transfer between the Bubble and Emulsion Phases in a Fluidized Bed

The rate of interphase mass transfer between the bubble and emulsion phases of a bubbling fluidized bed is of primary importance in all models for fluidized bed reactors. Many experimental studies have been reported, however, all these investigations have been carried out in fluidized beds operated at room temperature. In this work, the effect of the bed temperature on the interphase mass transfer is reported. Single bubbles containing argon – used as a tracer – were injected into an incipiently fluidized bed maintained at the required temperature. The change in argon concentration in the bubble was measured using a suction probe connected to a mass spectrometer. The effects of bed particle type and size, bubble size, and bed temperature on the mass transfer coefficient were examined experimentally. The interphase mass transfer coefficient was found to decrease with the increase in bed temperature and bubble size, and increase slightly with increase in particle size. Experimental data obtained in this study were compared with some frequently used correlations for estimation of the mass transfer coefficient.     

Interphase mass transfer with bulk flow normal to the phase boundary

The effect of bulk flow normal to the interface on the interphase mass transfer rate is analyzed by using a convective mass transfer coefficient, and a method of deriving the correct choice of the reference mole fraction in the bulk flow term is developed. The effect of the bulk flow and the definition of the proper reference mole fraction have been derived based on diffusion in a binary gas mixture across the boundary layer and expanded to the system of an interfacial gas-solid reaction. The results show that the bulk flow effect together with the proper choice of the reference mole fraction in the bulk flow term is important in obtaining an accurate expression of interphase mass transfer rate. In an extreme situation, the bulk flow effect can cause mass transfer to occur in the direction of increasing concentration. The theoretical development is applied to the rate analysis of the hydrogen reduction of silica. This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University.     

界面性质对气液传质的影响

界面性质对气液传质有重要影响。分子通过界面时需克服界面自由能，界面两侧的浓度不一致。本文导出了两者之间的关系