摘要:

AbstractIn this investigation of the effect of a cylindrical boundary on a spherical particle suspended in a moving viscous fluid the pressure drop due to the motion of fluid past a stationary sphere and the drag on the sphere are independently measured, and the sphere‐ to‐cylinder‐diameter ratios varying from 0.1250 to 0.3125 are studied at different positions of eccentricity. The investigation shows that in the range of Reynolds numbers from 0.1 to 40.0, based on the approach velocity to the sphere and the diameter of the sphere, the pressure drop due to the presence of a sphere and the drag on it can be represented by a semiempirical relationship containing two terms. One term, owing to the effect of the cylindrical boundary, is derived theoretically from the creeping‐motion equations which neglect inertial effects. The second term, owing to the inertial effects, is established from data on the drag coefficient of a sphere in on unbounded

ISSN:0001-1541    

DOI:10.1002/aic.690060111

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractIn 1856 Darcy observed that water flowed through a sand bed at a rate proportional to the area of the bed and to the difference between the upstream and dowstream hydraulic heads and inversely proportional to the bed thickness. Since that time many investigators have accumulated masses of data in support of numerous theoretical and empirical relationships for correlating and predicting pressure drop, flow rate, and fluid and bed properties. Naturally certain areas of research have received less attention than others.Among the areas receiving least attention are flow through beds composed of particles of identical shape but mixed size, flow through unconsolidated beds composed of small particles, and flow under the influence of a centrifugal driving force. Accordingly, the flow of liquids through unconsolidated beds of small spherical particles of mixed size was investigated in two laboratory centrifugal filters. Experimental conditions were such that the flow was laminar and the cakes were incompressible. While there was some difficulty in obtaining reproducibility of cakes, the data for any particular cake were correlated satisfactorily by the Darcy equation adapted for centrifugal filtration.

ISSN:0001-1541    

DOI:10.1002/aic.690060112

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractA correlation has been developed to predict the thermal conductivity of packed beds for various conditions of pressure, temperature, and particle size. The correlation takes into account the reduction in thermal conductivity of the gas phase at lower pressures when the mean free path of the gas molecules is of the same order as the distance between particles which are effective in transferring heat. Radiation becomes significant for large particles and high temperatures. A new relationship for the radiation contribution to the thermal conductivity of packed beds has been developed.

ISSN:0001-1541    

DOI:10.1002/aic.690060113

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractTechniques for solving the equilibrium flash problem are reviewed and a new technique especially adapted for use on automatic digital computers is developed. Instead of a single equation with multiple roots being solved by an iterative process, as is usually done, the problem is rephrased as a differential equation, and a numerical integration is made. The isothermal and isobaric flash problems can be handled with essentially the same equations. The method is particularly advantageous when a complete flash curve is required and the equations can be used when a linear model of the equilibrium flash process is required.

ISSN:0001-1541    

DOI:10.1002/aic.690060114

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractEquations are derived for predicting the effective thermal conductivity of beds of unconsolidated particles containing stagnant fluid. The effective thermal conductivity at these conditions, called thestagnant conductivity, is a function of the thermal conductivities of the solid and fluid phases, the void fraction, and, if radiation is important, the emissivity, mean temperature, and diameter of the solid particles. Comparison with the available experimental data indicates that the equations are satisfactory for fluids and solid particles of both high and low thermal conductivities.To extend the theory to beds of consolidated particles, it is supposed that consolidated beds are formed by partial clogging and cementing of beds of unconsolidated particles. With this assumption the theoretical equations for packed beds are extended to include such materials as sandstone and porous metals. The resulting expressions for the stagnant conductivity involve a consolidation parameter characteristic of the solid material. This quantity accounts for the heat transfer across the contact surfaces between cemented or clogged particles. The equations correctly predict the effect of void fraction and solid and fluid thermal conductivities on the heat transfer properties of sandstones and sintered metal systems.

ISSN:0001-1541    

DOI:10.1002/aic.690060115

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractThermodynamic analysis of phase‐equilibrium data is necessary for testing such data, for extension to new conditions, and for purposes of correlation and prediction of phase‐equilibrium behavior. While such analysis is common for low‐pressure systems, it is rare for high‐pressure systems owing to difficulties encountered in the definition of standard states. For a gaseous solute in the liquid phase it is proposed that the standard state be taken as the hypothetical liquid at the temperature and total pressure of the solution. The properties of this standard state are specified by the temperature and total pressure and by the specific volume which the substance would have if it did not experience a phase change. This standard state is useful since it is not a function of the solution but only of the substance being considered. For a condensable component in the gas phase it is convenient for most purposes to define the standard state as the ideal gas at the temperature and total pressure of the solution, but to separate the effect of composition on the activity coefficient from that of pressure, it is proposed to define the standard state as the real hypothetical gas at the solution conditions. To illustrate these ideas, activity coefficients are computed for several high‐pressure systems, and it is shown how these activity coefficients may be used in the correlation, testing, and extension of high‐pressure phase‐equ

ISSN:0001-1541    

DOI:10.1002/aic.690060116

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractThe effects of liquid superheat and surface roughness on boiling coefficients were investigated in a series of experiments in which water, acetone,n‐hexane, carbon tetrachloride, and carbon disulfide were boiled on a flat plate. In addition to the usual thermal measurements, the number of active boiling centers was determined, whenever possible, by visual means, and a quantitative measure of surface roughness was made. It was found that the number of active boiling centers on the plate increased with increasing surface roughness and that the calculated boiling coefficients were proportional to the one‐third power of the number of bubble columns rising from the heated surface.An equation has been derived relating boiling coefficients to fluid properties and the number of active boiling centers on a surface. A second equation, based on the theory of thermal fluctuations, has been proposed to relate the number of active boiling centers to the independent variables of surface‐roughness and temperature‐difference driving force. The limited data available have been found to follow this proposed relation.The results of this work suggest a quantitative method of relating the boiling coefficient to the character of the surface which may explain the discrepancies observed in the slopes of boiling curves reported in the literature and in the actual values reported for the boiling coefficients measured on different s

ISSN:0001-1541    

DOI:10.1002/aic.690060117

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractDetonation velocities were measured in mixtures of hydrogen and oxygen containing 25 to 75 mole % hydrogen at initial temperatures from 160° to 580°K. and initial pressures from 1/2 to 2 atm. The measurements were made in a number of tubes of different diameter to permit extrapolation to a tube of infinite diameter. Theoretical detonation characteristics were computed for the same range of conditions. The measured and computed velocities are in good agreement except in rich mixtures and at subatmospheric pressures. Schlieren photographs reveal that the detonation wave front is very thin for a stoichiometric mixture but degenerates to a complicated zone of interacting shock waves and turbulent combustion as the percentage of hydrogen is reduced. The detonation velocity is found to depend only slightly on initial temperature and pressure. The computed pressures behind the detonation and reflected waves are roughly proportional to initial pressure and to the reciprocal of the initial temperatur

ISSN:0001-1541    

DOI:10.1002/aic.690060118

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractFrom studies of annular packed beds wherein the heat flows purely radially, the authors obtained the coefficients of heat transfer on the inner tube surface, as well as the mean effective thermal conductivities of bed. The inner and outer diameters of the annular packed bed were 22 and 70 mm. respectively, and the packings shown in Table 1 were used. The wall film coefficients obtained with air flowing axially through the bed were correlated forNReM<600 by means of Equation (14).The coefficients of heat transfer for cylindrical packed beds reported previously by other observers were correlated also by Equation (14), with 0.054 used for values of αωin the rangeNReM<2,000.Consideration of Equation (14) in terms of a theoretical model of heat transfer showed that it was reasonable to apply it for the prediction of wall film coefficient, especially for low Reynolds number

ISSN:0001-1541    

DOI:10.1002/aic.690060119

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY

摘要:

AbstractMethods are developed for testing binary system phase‐equilibrium data for thermodynamic consistency when the more volatile component is above its critical temperature. The isothermal case with varying pressure and the isobaric case with varying temperature are considered individually. The rigorous form of the Duhem equation is employed rather than the simplified one, which for binary systems is inconsistent with the phase rule. Although derived for the specific case given in the title, the relationships developed are applicable to all conditions of binary systems. Sample calculations illustrating the methods are include

ISSN:0001-1541    

DOI:10.1002/aic.690060120

出版商:American Institute of Chemical Engineers    

年代:1960

数据来源: WILEY