Theory of Thermophoresis of Moderately Large Drops of Concentrated Solutions in Binary Gaseous Mixtures

We have derived a formula for the rate of thermophoresis of a volatile drop of a concentrated solution in a binary gaseous mixture with allowance for known effects that are associated with all types of slipping of the gaseous mixture along the drop surface and jumps of temperature and concentrations. An analysis of this formula has been performed for a number of limiting cases.     

多元混合工质池核沸腾传热实验研究

对R134a、丙烷（C3H8）、异丁烷（iC4H10）三种纯工质以及它们相应的二元混合物和三元混合物做了池核沸腾传热实验研究。加热面为紫铜表面,压力范围在0．1～0．6MPa。在纯工质实验数据基础上,分析物性、压力对沸腾传热系数的影响。相对于纯工质,非共沸混合工质沸腾传热系数有所降低,并且在高热流下趋势更明显。最后拟合出纯工质和混合工质沸腾传热关联式。     

多元非共沸混合物池内核态沸腾传热实验研究

对3种二元混合物和1种三元混合物进行了池内核态沸腾传热的实验研究,从系统压力、热流密度以及混合物组成3个方面进行了分析,指出了在三元混合物中高沸点工质对传热系数曲线变化的趋势具有重要影响.将实验结果同现有经验关联式的计算结果相比较,指出了现有关联式在计算不同混合物时出现的问题.     

Predicting the thermal-diffusion chacteristics of a hydrogen-oxygen binary gas mixture by the similarity method

Separation coefficients, thermal-diffusion separations, thermal-diffusion ratios, and thermal-diffusion constants are calculated for a hydrogen—oxygen binary gas mixture over a wide range of variations of temperatures and concentrations under rarefaction conditions. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 64–67, January–February, 1997.     

Adsorption of basic dyes from single and binary component systems onto bentonite: simultaneous analysis of Basic Red 46 and Basic Yellow 28 by first order derivative spectrophotometric analysis method

The present study deals with the simultaneous analysis and adsorption of Basic Yellow 28 and Basic Red 46 dyes in binary mixture onto bentonite. First order derivative spectrophotometric method was used for simultaneous analysis of BY28 and BR46 in binary mixtures. The adsorption experiments were carried out in a batch system. The mono- and multi-component Langmuir and Freundlich isotherm models were applied to experimental data and the isotherm constants were calculated for BY28 and BR46 dyes. The monolayer coverage capacities of bentonite for BY28 and BR46 dyes in single solution system were found as 256.4 mg/g and 333.3mg/g, respectively. It was observed that the equilibrium uptake amounts of BY28 and BR46 dyes in binary mixture onto bentonite decreased considerably with increasing concentrations of the other dye resulting in their antagonistic effect. The adsorption equilibrium data fitted more adequately to mono-component Langmuir isotherm model than mono-component Freundlich isotherm model, while the extended Freundlich isotherm model adequately predicted the multi-component adsorption equilibrium data at moderate ranges of concentration. Thermodynamic parameters showed that adsorption of BR46 and BY28 was endothermic and spontaneous in nature.     

Limits of recognition for simple vapor mixtures determined with a microsensor array

The "limit of recognition" (LOR) has been defined as the minimum concentration at which reliable individual vapor recognition can be achieved with a multisensor array, and methodology for determining the LORs of individual vapors probabilistically on the basis of sensor array response patterns has been reported. This article explores the problems of defining and evaluating LORs for vapor mixtures in terms of the absolute and relative component vapor concentrations, where the mixture must be discriminated from those component vapors and from the subset of possible lower-order component mixtures. Monte Carlo simulations and principal components regression analyses of an extant database of calibrated responses to a set of 16 vapors from an array of 6 diverse polymer-coated surface acoustic wave sensors are used to illustrate the approach and to examine trends in LOR values among the 120 possible binary mixtures and 560 possible ternary mixtures in the data set. At concentrations exceeding the LOD, 89% of the binary mixtures could be reliably recognized (<5% error) over some composite concentration range, while only 3% of the ternary mixtures could be recognized. Most binary mixtures could be recognized only if the constituent vapor relative concentration ratio, defined in terms of multiples of the LOD for each vapor, was < or =20. Correlations with the Euclidean distance(s) separating the normalized constituent vapor response vectors allow reasonably accurate predictions of the limiting recognizable mixture composition ranges for binary and ternary cases. Results are considered in the context of using microsensor arrays for vapor detection and recognition in microanalytical systems.     

Prediction of segregation behavior of binary mixture in a pulsed fluidized bed

A three-dimensional simulation is carried out to investigate the impact of pulsation flow on segregation behavior of binary mixture in a fluidized bed via the multi-fluid model. The simulated results are compared against the experimental data. The impacts of pulsation frequency and operating condition on flow and segregation behavior of binary mixture are discussed. The results reveal that an excessive increase of pulsation frequency and operating temperature is not beneficial to the enhancement of segregation efficiency. The pulsation frequency plays a more important role in segregation efficiency under a small size discrepancy of binary mixture. Meanwhile, the effect of pulsed air flow waveform on segregation efficiency of particles is also analyzed.     

Spectral characteristics of a binary dye-mixture laser

We have investigated laser action in a binary mixture of dyes, Rh-6G and DCM, resulting in tunable laser emission over an extended frequency region. The two dyes absorb the same pump radiation but fluoresce over frequency ranges that are shifted with respect to each other, thereby resulting in extended tunability. Following a time-dependent analysis of a rate-equation model that describe the operation of such a laser, theoretical estimates for optimum dye concentrations and the corresponding extension of the laser tuning range have been obtained.     

Influence of the coefficient of vaporization on the parameters of the gas near the surface

The dependence of the coefficient of concentration jump on the coefficient of vaporization for a diluted binary mixture, when the concentrations of the components are significantly different, has been investigated. The analytical expression of the concentration jump for the case where the frequency of collisions of molecules is in proportion to their velocity has been obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 121–126, March–April, 2007.     

Estimating the segregation of a granular bed subjected to vibration in various modes

We present in this paper a DEM study on the segregation behavior of vibrated binary mixture, by focusing on the influence of vibration modes. The numerical simulation program includes a number of vibration tests on a binary mixture in a cylindrical bed, which are performed under different vibration velocity modes, frequencies and amplitudes. We utilize a novel segregation index, namely, the graphic segregation index (GPSI), to characterize the segregation behavior and trace the segregation evolution for binary mixtures. The numerical simulations reveal that the influence of velocity mode is coupled with that resulting from vibration frequency. The binary mixture tends to segregate at a low frequency, with little influence exerted by the velocity mode, whereas it does not fulfill complete segregation at a relatively high frequency, with the vibration frequency having some limited impact on the segregation behavior. Given an intermediate frequency the segregation behavior of the mixture is a little mixed for various velocity modes. It is also found that increasing vibration amplitude enhances the segregation degree of binary mixture. The operation of percolation mechanism in the broad sense is assumed to be primarily responsible for the occurrence of segregation in this study, and this alleged percolation mechanism, as an overall effect, is a result of three effects: the random gap effect, the size-and-mass dependent acceleration and the intrusion and expulsion effect.     

Experimental study of the refrigeration cycle performance for the R744/R290 mixtures

A new binary mixture of R744 and R290 as an alternative natural refrigerant to R13 was first presented in this paper. Its environmental performance is friendly. It has an ODP of zero and GWP smaller than 20. Experimental studies for this mixture and R13 were performed on a cascade refrigeration system only with modification to capillary in low-temperature circuit. COP and refrigeration capacity of this binary mixture were higher than those of R13, at the same time, condensing pressure, evaporating pressure, compression ratio, and discharge temperature were also higher than that of R13 when the high-temperature circuit of cascade refrigeration system was kept invariable. The new binary mixture of R744 and R290 is considered as a promising alternative refrigerant to R13 when the evaporator temperature is higher than 201 K.     

Limits of recognition for binary and ternary vapor mixtures determined with multitransducer arrays

The discrimination of simple vapor mixtures from their components with polymer-coated multitransducer (MT) arrays as a function of the absolute and relative concentrations of those components is explored. The data set consists of calibrated responses to 11 organic vapors from arrays of 5 or 8 microsensors culled from a group of 5 cantilever, 5 capacitor, and 5 calorimeter transducers coated with 1 of 5 different sorptive-polymer films. Monte Carlo methods are applied to simulate error-enhanced composite responses to all possible binary and ternary mixtures of the 11 vapors, and principal component regression models are established for estimating expected rates of recognition as a function of mixture composition. The limit of recognition (LOR), defined as the maximum recognizable mixture composition range, is used as the metric of performance. With the optimal 8-sensor MT array, 19 binary and 3 ternary mixtures could be identified (i.e., discriminated from their components) with <5% error. The binary-mixture LORs are shown to decrease with increases in the baseline noise levels and random sensitivity variations of the sensors, as well as the similarity of the vapors. Importantly, most of the binary LOR contours are significantly asymmetric with respect to composition, and none of the mixtures could be recognized with <5% error at component relative concentration ratios exceeding 20:1. Discrimination of ternary mixtures from their components and binary subcomponent mixtures is possible only if the relative concentration ratio between any two of the components is <5:1. In comparing binary LORs for the best five-sensor single-transducer (ST) array to those of the best five-sensor MT array, the latter were larger in nearly all cases. The implications of these results are considered in the context of using such arrays as detectors in microanalytical systems with upstream chromatographic modules.     

Calculation of the straight and cross diffusion coefficients of a two-component mixture in a microporous zeolitic structure

A method is given which enables calculation of straight and cross diffusion coefficients of a two-component mixture adsorbed on a microporous adsorbent at constant pressure conditions. In particular, the method involves the solution of the reverse problem of calculating the matrix of diffusion coefficients on the basis of the experimental uptake curves of binary mixture adsorption. In this Paper, the method is illustrated for a binary n-hexane—ammonia mixture adsorbed on CaA type zeolite. The occurrence of a negative cross diffusion coefficient is also shown.     

Permeation of aromatic solvent mixtures through nitrile protective gloves

The permeation of binary and ternary mixtures of benzene, toluene, ethyl benzene and p-xylene through nitrile gloves were investigated using the ASTM F739 test cell. The more slowly permeating component of a mixture was accelerated to have a shorter breakthrough time than its pure form. The larger differences in solubility parameter between a solvent mixture and glove resulted in a lower permeation rate. Solubility parameter theory provides a potential approach to interpret the changes of permeation properties for BTEX mixtures through nitrile gloves. Using a one-dimensional diffusion model based on Fick's law, the permeation concentrations of ASTM F739 experiments were appropriately simulated by the estimated diffusion coefficient and solubility. This study will be a fundamental work for the risk assessment of the potential dermal exposure of workers wearing protective gloves.     

Isothermal slip of a binary gas mixture along a solid surface

This paper investigates Couette flow of a binary mixture of a rarefied gas between two flat plates. An analytical expression for the rate of isothermal slip of a binary mixture of the rarefied gas along the surface is obtained.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 4, pp. 683–686, April, 1977.     

二元气-固流化系统临界流化速度的研究

在直径为4cm的有机玻璃流化床中,对由不同尺寸和质量分数的铁矿石和煤颗粒组成的二元气-固流态化系统进行了流化特征的实验研究,得到了该系统的流化特性曲线,给出了临界流化速度和二元系统混合颗粒平均直径之间的关系,用该关系式对临界流化速度进行了预测,并且将预测值和实验值进行了比较。结果表明,当煤颗粒的质量分数为10%时,临界流化速度umf与颗粒直径的平方dm2的关系为umf=0.13dm2+1.2;当煤颗粒的质量分数为20%时,两者的关系变为umf=0.12dm2+1.2,预测值与实验值误差在10%以内。     

Influence of the Evaporation Coefficient and Temperature Jumps on the Thermophoresis of a Moderately Large Volatile High‐Viscosity Sphere in a Binary Gas Mixture with Allowance for Volume Thermodiffusion and Stefan Effects

The theory of a uniform thermophoretic motion of a volatile highviscosity sphere with the phase transition of one component of a moderately rarefied binary gas mixture on its surface has been constructed on the basis of the hydrodynamic method in the regime with slip. The relative influence of the evaporation coefficient and the boundary temperature jumps on the distributions of the velocities, temperatures, and concentrations of the volatile component and the thermophoresis rate has been analyzed. Allowance has been made for the thermodiffusion terms, Stefan effects, and the heat due to the convective transfer of the substance of the condensed phase. The formula obtained has wider limits of application than the existing results. The conclusions of the traditional theories are successfully generalized to the cases of weak and moderately strong processes of diffusion evaporation of a single highviscosity droplet that moves in a nonuniformly heated binary mixture of gases.     

Thermodiffusion in a Hydrogen–Nitrogen Gas System

Characteristics of thermodiffusion molecular mass transfer of a binary frozen hydrogen–nitrogen gas mixture are predicted by the method of entropy similarity. Calculations are made within a wide range of variation of temperatures and concentrations at normal pressure.     

A dielectric binary mixture formula with an interaction term

A new dielectric binary mixture formula that generalizes Beer's equation is derived by imposing an effective medium theory on the simple rule of mixtures modified by the addition of an interaction term. Dielectric constants of the binary system carbon tetrachloride/1,2-dichloroethane measured at different frequencies and of carbon tetrachloride/butan-2-ol at different temperatures are used to test the applicability of the new mixture formula. Goodness of fit to the experimental data is found.     

Heat transformation with the ternary working fluid TFE-H2O-E181: Transformation de chaleur avec le fluide de travail ternaire TFE-H2O-E181

As shown in previous papers, the binary mixture of trifluoroethanol (TFE) and tetraethylene-glycoldimethylether (E181) seems to be advantageous for absorption heat pumps and absorption heat transformers. Both substances are completely miscible and applicable in a wide temperature range from below 0 up to 160°C. The density of TFE vapour is much higher than that of water, so that condenser and evaporator become smaller than in processes with water as a working substance. Because of the fairly low thermal conductivity and the low enthalpy of evaporation of TFE it is, however, advantageous to use TFE-water instead of pure TFE with E181 as working substances. The present paper deals with the thermophysical properties of this ternary mixture. The thermal stability, vapour-liquid equilibrium, density and viscosity were measured. The enthalpy of the ternary mixture was predicted from data for the three binary subsystems. As a study of the single-stage absorption heat transformer shows, up to 15 mass% or almost 50 mol% of TFE in the mixture TFE-E181 can be replaced by water. The COP of a process working with the ternary mixture is slightly higher than that of a process working with the binary mixture TFE-E181. Because of the higher thermal conductivity and enthalpy of evaporation of TFE-water compared with pure TFE, the heat transfer is improved. Also, the costs for the mixture are reduced.