摘要:

The problem of convective diffusion from and reaction within the circulating flow inside a two-dimensional rectangular cavity is studied. The circulation is of the type induced by an external flow. Mass transfer occurs across the interface between the cavity and the external flow. A reactant may diffuse into the cavity from the external flow. The equations of steady motion and transient convective diffusion and chemical reaction are solved numerically. An enhancement factor is defined which quantifies the effectiveness of internal circulation in promoting diffusion and reaction. The dependence of this enhancement factor on geometry (cavity aspect ratio), Peclet number, and kinetic parameters is displayed.

ISSN:0098-6445    

DOI:10.1080/00986448308940051

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Composition and boiling points of the azeotrope comprised of 2-methyl-l,3 butadiene and normal pentane are reported within the 53.03-101.60 K Pa pressure range. The uncertainties in the measured variables are: 0.001 mole fraction, 0.1 K Pa pressure and 0.03 K temperature. The parameters and their temperature trend. for the Wilson and the UNIQUAC solution models are also reported. These last parameters were extrapolated to predict the vapor-liquid equilibrium in the same system at 310.93, 316.48 and 322.04 K, obtaining satisfactory results at 310.93 K. and fair results at the other two temperature levels. Since the experimental results from this study cover better than others the range of likely application, its use is recommended in preference to earlier reported data.

ISSN:0098-6445    

DOI:10.1080/00986448308940052

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

At present, in a number of papers1-4dealing with the analysis of catalytic processes which take place in several phases, the problem is discussed of the assessment of the effectiveness of a catalyst pellet as well as of the relation between dry and wet surfaces. In most cases, assumptions are made of uniform pellet impregnation by liquid5or the correspondence between wet external and internal pellet surfaces.1In this case, capillary and porous structure effects of the pellet are completely ignored. Characteristics of the process become complicated in the presence of phase transfers of the liquid—gas type and chemical reactions in both phases.3.6

ISSN:0098-6445    

DOI:10.1080/00986448308940053

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The lack of success of existing theories in describing viscosity of molecular liquids appears to be due to at least two difficulties. The mechanisms of viscous momentum transfer have not been identified, and the thermal motions of molecules can not be described until the spatial arrangement of molecules in a shearing liquid is known. This paper presents the results of an effort to identify the mechanisms of viscous momentum transfer. A model is proposed and a relation is derived from it that precisely fits viscosity data for a wide variety of Newtonian liquids. The effects of the spatial distribution of thermal motions and of intermolecule attraction are represented as parameters together with a Debye-like temperature. Values of these parameters are found from fitting the relation to published data. The parameters are found to be sensitive to molecular weight and to molecular configuration. Frequencies of interaction of molecules in the direction of the velocity gradient are of the order E 10 s−1. Abrupt shifts in these parameters with increasing temperature are found for paraffins at temperatures slightly above their melting points that are interpreted as disaggregation of molecules. Other abrupt shifts in the parameters at high temperatures for mercury and alcohol are interpreted as a change in the momentum transfer mechanism. Correlation of the parameters of the relation with molecular properties promises to provide predictive value. The relation provides a framework for further theoretical development.

ISSN:0098-6445    

DOI:10.1080/00986448308940054

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The problem in title is analyzed for dilute solutions with no substantial intenonic effects and with the diffusivity and the electrophoretic mobility being related via the Nernst-Einslein equation. The case is considered of only the positive ion reacting at the electrodes, being produced at the anode and consumed at the cathode, With the electroneutrality condition as a first approximation, the equations for the average concentration and the electric field are decoupled and solved analytically. Then the deviation from electroneutrality is calculated in the second approximation via Poisson' s equation. The problem has a steady state if the current is smaller than a certain value. With this analysis and measurements of concentrations at different times, electrophoretic mobilities of the two ions can be calculated. The implications for interpreting measurements in microelectrophoresis and electrophoretic mass transport analysis are discussed

ISSN:0098-6445    

DOI:10.1080/00986448308940055

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

There are various correlations available for predicting heat transfer coefficients during forced convective two-phase flow. The present work was undertaken to gather heat transfer rate data for the steam-water system and to evaluate (and if necessary, to modify) the available correlations in light of those data.

ISSN:0098-6445    

DOI:10.1080/00986448308940056

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A careful scrutinity of the literature shows on one hand the crucial industrial problems of selectivity in gas-liquid contactors and on the other hand, reveals the limited number of theoretical and experimental studies on the topic. A theoretical approach is proposed with the scheme

ISSN:0098-6445    

DOI:10.1080/00986448308940057

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A generalized bubble rise velocity correlation is developed to cover the range of conditions:

ISSN:0098-6445    

DOI:10.1080/00986448308940058

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0098-6445    

DOI:10.1080/00986448308940059

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor