MOLECULAR PRINCIPLE OF CORRESPONDING STATES FOR VISCOSITY AND THERMAL CONDUCTIVITY OF FLUID MIXTURES

Conformal solution theory is developed for the viscosity and thermal conductivity of fluid mixtures. The procedure involves expanding the transport coefficient for the mixture about the value for an ideal solution, using groupings of the potential parameters and molecular mass as expansion coefficients. The parameters for the ideal solution are chosen so as to annul the first-order term in this expansion, thus encouraging rapid convergence. This yields mixing rules (similar to those of the van der Waals 1 theory for thermodynamic properties) for the potential parameters and molecular mass of the reference fluid. Reference fluid properties are obtained from pure fluid corresponding states correlations

By making calculations for dilute gas mixtures and comparing with Chapman-Enskog theory, it is found that the first-order theory works well for mixtures of quite widely different energy parameters (ε) and molecular masses; it is more sensitive to the size difference of the molecular components, however. For cryogenic liquid mixtures composed of simple liquids good results are obtained using two-parameter corresponding states for the reference fluid. For polyatomic fluids it is necessary to use a three-parameter corresponding states approach for the pure fluids. A method of introducing a third parameter, while retaining the simplicity of having only two independent variables, is used for such fluids. Good results are obtained for a variety of binary mixtures. The method is of particular value for multicomponent fluids. Thus, without fitting any parameters from ternary data the theory predicts viscosities for the system carbon tetrachloride/n-hexane/benzene over the full composition range with a standard deviation of only 1.69%.     

GENERALIZED CORRESPONDING STATES CORRELATIONS FOR THE VISCOSITY AND THERMAL CONDUCTIVITY OF AQUEOUS ELECTROLYTE SOLUTIONS

Corresponding slates correlations have been developed for the viscosity and thermal conductivity of aqueous electrolyte solutions for a wide range of temperatures, pressures, and concentrations. For viscosity, the Vogel-Tamann-Fulcher equation has been generalized using the corresponding states theory, and extended to include pressure effects. Twenty six aqueous electrolyte solutions, including both monovalent and multivalent electrolytes, have been studied and a generalized correlation has been developed for viscosity, with four system dependent parameters. For thermal conductivity, a similar corresponding states based correlation has been developed. Twenty three aqueous electrolyte solutions were studied for thermal conductivity and a generalized equation was obtained that requires only two System dependent parameters. With both correlations, the maximum error is usually within 10% of the experimental values, with the average errors being much less. Additional systems can also be included in both correlations in a straightforward manner.     

氟里昂类物质的饱和液体黏度和导热系数相互推算的对应态方法

引言 导热系数和黏度是重要的运输性质,是工程设计和应用中的基础数据.     

EVALUATION OF THE ORIGINAL AND THE EXTENDED CORRESPONDING STATES PRINCIPLE FOR REFRIGERANTS

The corresponding states and extended corresponding states principles have been evaluated for refrigerants. In the two corresponding states techniques the Riedel and Wagner vapour pressure correlations have been used to express the vapour pressure for the reference fluids. As reference fluids CFC12 and HFC134a have been used. These two fluids cover the acentric factor interval wherein refrigerants are found. Parameters have been estimated for CFC12 and HFC134a according to the Reidel and Wagner vapour pressure correlations used in the extended corresponding states principle. Experimental vapour pressure data for CFC12 and HFC134a have been used to estimate parameters according to Riedel and Wagner used in the hypothetical fluid and deviation function used in the corresponding states principle.

The Riedel and Wagner correlations are of equal accuracy in vapour pressure calculations. The results from the corresponding states and extended corresponding states principle are comparable due to the conformity between the Riedel and Wagner correlation, but improved results are obtained in comparison with the Lee-Kesler vapour pressure correlation in acentric factor interval studied.     

GENERALIZED CORRESPONDING STATES CORRELATION FOR THE SURFACE TENSION OF LIQUIDS AND LIQUID MIXTURES

The simple principle of corresponding slates can be generalized lo include substances that depart from strict conformality by introducing state-dependent shape factors. This approach has been applied to the surface tension of simple inorganic compounds, hydrocarbons and their mixtures. Good agreement, generally within experimental error, has been obtained with available experimental results for both pure compounds and mixtures.     

PREDICTION OF THERMAL CONDUCTIVITY AND VISCOSITY FOR SOME FLUIDS IN THE NEAR-CRITICAL REGION

The objective of this work was to develop general, simple and accurate expressions to predict the peculiar behavior of thermal conductivity and viscosity in the near-critical region. Expressions were determined for (a) variation of thermal conductivity as a function of temperature and density or pressure for carbon dioxide, water, and ammonia, and for (b) variation of viscosity as a function of temperature and density or pressure for carbon dioxide, water, and nitrogen. The predicted results based on the developed expressions showed a very good agreement with the available thermal conductivity experimental data and an excellent agreement with the available viscosity experimental data     

EFFECTIVE THERMAL CONDUCTIVITY OF BINARY MIXTURES AT HIGH SOLID TO GAS CONDUCTIVITY RATIOS

The effective thermal conductivity of single size and binary mixtures of packed particle beds with stagnant gas at high solid/gas conductivity ratios is determined by a deterministic, unit cell approach. The model results are shown to be in good agreement with experimental data for various gas pressures and solid to gas thermal conductivity ratios up to 1300. A set of correlations for effective conductivity of binary mixtures as a function of gas pressure and particle size is derived. The effect of particle swelling on the effective conductivity of binary mixtures is studied by performing a parametric study of the contact area between the particles     

液体烃的分子结构与导热率

分析了国际化工领域著名的Latini等式的不足后,以张克武提出的气体不平衡状态理论方程导出的液体导热率理论方程和理论定则为依据,提出液体烃导热率方程;经用各类液体烃76种362个实验数据检验,平均误差1.78％,显著优于前人公式。有重要的理论意义与应用价值。     

CORRELATION OF CRITICAL LOCI FOR FLUID MIXTURES

The hard-sphere three-parameter equation of state proposed in our previous investigation was applied to correlate binary critical loci of alkane-alkane, aromatic-aromatic, hydrocarbon-inorganic gas and systems containing oxygenated hydrocarbons including those exhibiting type Ⅲ behaviors as classified by van Konynenberg and Scott. A new procedure was also presented which simplified mathematical manipulations and permitted the reduction of the computation time.Results were compared with those obtained by Patel-Teja equation with temperature-dependent binary interaction parameters. Significant improvements were achieved by the proposed equation with temperature-dependent parameters.In addition parameters obtained from the critical locus calculations were used to predict vapor-liquid equilibria of hydrogen-carbon monoxide and hydrogen-carbon dioxide systems. Prediction accuracies were found to be very satisfactory.     

VAPOR-LIQUID EQUILIBRIA FOR MIXTURES OF TOLUENE AND POLYSTYRENE WITH DIFFERENT MOLECULAR WEIGHTS

An experimental system for measuring the VLE of polymer solutions based on the staticvapor-pressure method has been established,VLE data for mixtures of toluene and polystyrene withdifferent molecular weight covering a wide range from 2.98×10~3 to 3.84×10~6 were obtained at 35℃.The reduced pressure p/p°versus weight fraction W plot is found to be independent on the molecularweight of the polymer within the experimental error.Calculated activity coefficients are also independenton the molecular weight.However,for the Flory-Huggins interaction parameter x,not only a strongconcentration dependence is observed,but also the molecular weight of the polymer exerts definiteinfluence.Generally,the parameter x slightly increases as the molecular weight of the polymer decreasesespecially when the molecular weight is low.The dependence of the parameter x on the molecularweight can be neglected when the molecular weight of polymer is greater than 1.00×10~4.     

CRITICAL POINT PREDICTION USING A MULTI-FLUID GENERALIZED CORRESPONDING STATES PRINCIPLE

The Generalized Corresponding States Principle (GCSP), based on the properties of two non-spherical reference fluids, offers flexibility and ease of computation for the prediction of thermodynamic and transport properties of pure fluids and fluid mixtures. In this work, the multi-fluid GCSP is used for the calculation of the critical properties of mixtures. Classes of mixtures studied include those containing: (1) simple spherical molecules; (2) large quasi-spherical molecules such as the cyclosiloxanes; (3) both spherical and large nonspherical molecules such as those important in supercritical extraction and hydrocarbon processing; and (4) molecules exhibiting strong dipole moments. The advantages of the GCSP method are outlined, particularly for fluids not usually amenable to conventional corresponding states treatments.     

CRITICAL POINT PREDICTION USING A MULTI-FLUID GENERALIZED CORRESPONDING STATES PRINCIPLE

The Generalized Corresponding States Principle (GCSP), based on the properties of two non-spherical reference fluids, offers flexibility and ease of computation for the prediction of thermodynamic and transport properties of pure fluids and fluid mixtures. In this work, the multi-fluid GCSP is used for the calculation of the critical properties of mixtures. Classes of mixtures studied include those containing: (1) simple spherical molecules; (2) large quasi-spherical molecules such as the cyclosiloxanes; (3) both spherical and large nonspherical molecules such as those important in supercritical extraction and hydrocarbon processing; and (4) molecules exhibiting strong dipole moments. The advantages of the GCSP method are outlined, particularly for fluids not usually amenable to conventional corresponding states treatments.     

APPARATUS FOR MEASURING THERMAL CONDUCTIVITY OF REFRACTORIES*

An apparatus for measuring the thermal conductivity of refractories, is described in detail, and results are shown for several types of insulating refractories. Comparisons are madc from data which were obtained on a low-temperature plate tester, and the effect of several variables on measured heat flow are discussed.     

EFFECT OF MAGNETIC FIELD-DEPENDENT VISCOSITY ON THERMAL CONVECTION IN A FERROMAGNETIC FLUID

This article deals with the theoretical investigation of the effect of magnetic field-dependent (MFD) viscosity on a layer of ferromagnetic fluid heated from below subject to a transverse uniform magnetic field. For a flat fluid layer contained between two free boundaries, an exact solution is obtained using a linear stability analysis and normal mode analysis method. For the case of stationary convection, the MFD viscosity has a stabilizing effect, whereas the departure of linearity in the magnetic equation of state has a destabilizing (or stabilizing) effect on the system under certain conditions. The critical wave number and critical magnetic thermal Rayleigh number for the onset of instability are also determined numerically for large values of buoyancy magnetization, and results are depicted graphically. The principle of exchange of stabilities is valid for the ferromagnetic fluid heated from below.     

Eyring模型的修正及液体混合物粘度的研究

<正>在化工传质和流体力学中,粘度是一个不可缺少的物性.为此,已建立了许多计算液体混合物粘度的经验和半经验方程,其中不少建立在 Eing粘度理论的基础上,但这些方程都含有 2个或多个     

SPHERICAL FURNACE CALORIMETER FOR DIRECT MEASUREMENT OF SPECIFIC HEAT AND THERMAL CONDUCTIVITY*

A spherical calorimeter was constructed for measuring true specific heat and thermal conductivity. It was formed of two concentric spherical platinum shells, and a spherical sample was fitted into the inner shell. Electric heat was supplied at the center of the sample, and the calorimeter was housed in a spherical electric furnace. Thermal conductivity was measured by determining the inner and outer sample temperatures at steady heat flow using the equation of heat conduction in a sphere; specific heat was measured by noting the temperature rise of the sample with a known heat input while maintaining the calorimeter shells near the adiabatic condition; and a correction for heat leakage was made by using the conductivity determination to calculate this factor. Specific heat and thermal conductivity measurements were made on quartz sand, chrome refractory cement, four types of insulating firebrick, and 85% magnesia insulation over a total temperature range of 100° to 2200°F. The estimated accuracy of specific heat measurement of 3 to 5% is consistent with engineering requirements. No estimate of accuracy can be given as yet for thermal conductivity results.     

含自缔合流体混合物的分子热力学模型

缔合流体及其混合物的亥氏函数和压缩因子可表示为物理相互作用的贡献和化学缔合作用的贡献两部分之和。前者可采用作者建立的非缔合流体及其混合物的分子热力学模型;作者从分子间相互作用位能函数的粘滞球模型出发,利用统计力学方法确定了混合物中自缔合作用的贡献。模型中分子间的缔合参数完全可由纯物质性质确定,而只在混合物方阱位能参数的计算中引入可调的二元相互作用参数。对于含有一个自缔合组分的二元混合物常压和高压汽液平衡数据的关联结果令人满意。     

共聚高分子溶液的分子热力学模型

引　言共聚高分子因具有很多均聚高分子所没有的性质而受到人们的广泛关注 .但文献中发表的有关共聚高分子系统的汽液相平衡 (ＶＬＥ)数据较少 ,能够用于关联或预测的分子热力学模型也不多 .最常用的模型是基于密堆积格子模型的Ｆｌｏｒｙ -Ｈｕｇｇｉｎｓ理论及其改进模型 .近年来 ,在严格的统计力学理论基础上建立非格子的链状流体状态方程引起了人们更大的兴趣 ,并相继建立了一些具有实用价值的状态方程[1～ 5] .对于共聚高分子系统 ,Ｈｉｎｏ等人[6 ]建立了实用的状态方程 ,Ｂａｎａｓｚａｋ等人[7] 在热力学微扰理论 (ＴＰＴ1)的基础上…     

高炉炭砖的导热系数及其影响因素

对微孔、半石墨质和普通等级炭砖试样的导热系数与温度的关系做了回归分析,得到了导热系数和温度的关系表达式,由此,可以从室温导热系数预测高温导热系数。另外,还计算了导热系数与体积密度、显气孔率、透气度和原料等级之间的相关系数。结果表明,导热系数与透气度和原料等级有一定的相关关系,而与体积密度和显气孔率无关。     

A GENERALIZED EQUATION OF STATE FOR POLAR AND NON-POLAR FLUIDS BASED ON FOUR-PARAMETER CORRESPONDING STATES THEOREM

A new generalized equation of state for polar and non-polar fluids based on the corresponding states theorem is developed, f n addition to two critical parameters, four parameters are required; two for the calculation of volumetric properties and two for the calculation of pressure and departure functions. Parameteres for more than 100 polar and non-polar fluids are given. Comparison with the existing generalized state equations showed that the new method, in general, shows a better agreement with the experimental data. The absolute average deviation is 0.48% for the vapor pressure and 0.32% for the saturated liquid volume.