bluuebunny/crossref_metadata_2025_split huggingface dataset:
A generalized equation for computer calculation of liquid densities
Authors: Yen Lewis C. , Woods S. S. 
Published: June 2004

AbstractA generalized equation explicitly relating reduced density to reduced temperature and reduced pressure has been developed for calculating liquid densities of pure compounds on a digital computer. The analytical formulation is based mainly on a modified corresponding states principle and the graphical correlation of Lydersen, Greenkorn, and Hougen. The calculated densities from the equation reproduce the literature data within 2% for sixty‐two saturated liquids and nineteen compressed liquids.With the aid of a pseudocritical method and a generalized equation of vapor pressure, the same equation is readily applied to the estimation of liquid mixture densities. The method of Prausnitz and Gunn is chosen for the evaluation of pseudocritical constants. For fifteen binary systems, one ternary system, and one quinary system, the one hundred fifty‐nine calculated densities agree with the literature data to within 3%. This method is limited to pseudoreduced temperatures less than 1.0.
The stability of Couette flow between rotating cylinders in the presence of a radial temperature gradient
Authors: Walowit J. A. 
Published: June 2004

AbstractThe effects of viscosity and density variations due to an imposed radial temperature gradient on the stability of Couette flow between rotating cylinders are investigated. The annular spacing between the cylinders is assumed to be small compared with the mean radius. The fluids considered are water and 50% aqueous glycerol. Free convection due to gravity is not considered.Approximate solutions to the stability equations are obtained by the Galerkin method. Computations are restricted to the case where the outer cylinder is at rest. For the cases studied, the effects of radial convection were found to be small but the effects of the temperature dependence of viscosity were appreciable. The critical Taylor number based on the mean temperature viscosity was found to decrease as the viscosity variation became more pronounced and as the Prandtl number increased.
Tracking function approach to practical stability and ultimate boundedness
Authors: Paradis W. O. , Perlmutter D. D. 
Published: June 2004

AbstractA graphical method of analysis is presented for studying the practical stability and ultimate boundeness of autonomous second‐order systems. It is argued that these measures of stability are in many cases more germane to design than Liapunov stability. The method incorporates much of the geometric character of a Liapunov analysis, but it is shown that a Liapunov function, relatively difficult to obtain, can be replaced by a set of easily postulated scalar functions which collectively yield the required stability information. Examples are given which demonstrate the use and effectiveness of the method.
Rates of hydrogen chloride oxidation
Authors: Jones Alva M. , Bliss Harding , Walker Charles A. 
Published: June 2004

AbstractRates of oxidation of hydrogen chloride (the Deacon process) were measured in a recycling reactor with chromic oxide catalysts. The temperatures were 325° to 355°C., and a wide range of reactant compositions was used. The reverse reaction was also explored at 355° to 370°C. The experimentation was carefully tested to be sure that the construction material did not affect the results and that diffusional effects were absent.An empirical equation is described which correlates well the rates of oxidation and fits the original observed data. It is capable of predicting reasonably well some of the observed rates of the reverse reaction.
Direct contact heat transfer with change of phase: Spray‐column studies of a three‐phase heat exchanger
Authors: Sideman Samuel , Gat Yehuda 
Published: June 2004

AbstractTransfer characteristics are presented for a perforated plate‐spray column in which a volatile dispersed phase evaporates while rising in the continuous, counterflowing, immiscible phase. Optimal column heights, volumetric transfer coefficients, holdup, and foam heights are reported as functions of flow rate and temperature approach for a pentane‐water system, A comparison with related studies is presented.
The dehydrogenation of isopropanol on catalysts prepared by sodium borohydride reduction
Authors: Mears David E. , Boudart Michel 
Published: June 2004

AbstractNickel catalysts reduced with sodium borohydride have been found to be active for the liquid phase dehydrogenation of isopropanol. The activity, per unit weight of catalyst, is at least as high as that of Raney nickel. Promotion of the new catalyts with small amounts of chromium has been explained by an increase in surface area. Indeed, the activity per unit surface area of the unpromoted and promoted nickel catalysts is constant over a sevenfold range of surface area.
Axial laminar flow of a non‐Newtonian fluid in an annulus
Authors: McEachern Donald W. 
Published: June 2004

AbstractThe equation of motion has been solved for steady axial, laminar, isothermal flow of an Ellis model fluid in a conduit of annular cross section. Tables are presented which may be used to obtain flow curves for annular flow of fluids whose Ellis parameters are known.The Ellis fluid predictions are compared to experimental data on dilute polymer solutions flowing in annuli. Ellis fluid predictions of flow curves are also compared to those predicted by the generalized Newtonian fluid and the power law fluid.
Catalytic hydrogenation of propylene and isobutylene over platinum. Effect of noncompetitive adsorption
Authors: Rogers G. B. , Lih M. M. , Hougen O. A. 
Published: June 2004

AbstractA mathematical and kinetics model is presented for reactions catalyzed by solid surfaces where both competitive and noncompetitive adsorption take place, a situation that may be general in reactions between large and small molecules catalyzed by solid surfaces.In the adsorption of large molecules steric hindrance or multiple site adsorption cause maximum surface coverage of such molecules before all sites are occupied. This does not, however, preclude further adsorption of small molecules on the remaining isolated vacant sites nor does it preclude further surface reaction. The overall reaction model for such conditions may be expressed as
equation image
This particular model has been evaluated for the catalytic hydrogenation of propylene and isobutylene with the expectation that it may be useful in reactions that are of industrial importance. A reaction model based on either competitive adsorption or noncompetitive adsorption alone fails to correlate the experimental data.In these two reactions maximum rates occur at olefin concentrations below 5 mole % and the catalytic adsorption constants for the olefins are a hundredfold greater than for hydrogen. This reaction model is similar to that proposed by Bond and Turkevich (15), who have further demonstrated through the deuteration of propylene that the actual mechanism of the reaction is much more complicated.
The prediction of liquid mixture enthalpies from pure component properties
Authors: Osborne Adam 
Published: June 2004

AbstractThe paper presents a procedure for calculating liquid mixture enthalpies, whereby a liquid heat of mixing is added to the molal average of the pure liquid enthalpies. The heat of mixing for the mixture is calculated from the heats of mixing of the binary systems at infinite dilution, which in turn are determined with a proposed molecular model for liquid mixing, and a postulate of acceptance. The two cases where the solute in the binary system is more volatile and less volatile than the solvent are treated separately. The case is also considered where a component of the liquid mixture is above its critical temperature; a pure liquid enthalpy is defined and justified for such pseudo liquids, and heats of mixing are then calculated as for actual liquids. Results are compared for four nonpolar binary systems, three with experimental data, and one with data calculated by other means. Data for a number of gases dissolved in water are also considered. The agreement in all cases is excellent.
Turbulent flow in annular pipes
Authors: Macagno Enzo O. , McDougall David W. 
Published: June 2004

AbstractAn extension to annular conduits of the well‐known method of calculating the resistance coefficient for turbulent flow in circular pipes is presented. The method is new in that it does not borrow any information from laminar flow theory; it gives, therefore, a location for the maximum velocity based only on turbulent flow characteristics. Expressions and a few essential graphs are given for the average as well as inner‐ and outer‐wall resistance coefficients for both hydraulically smooth and rough regimes and also for the transitional regime. A comparison with available experimental information for fully developed turbulent flow is presented.
Modified description of wave motion in a falling film
Authors: Massot Claude , Irani Farhad , Lightfoot E. N. 
Published: June 2004

AbstractThe presence of gravity‐capillary waves at the surface of a viscous falling film has been studied theoretically by a more rigorous linear treatment than presently available.The present analysis is based on the assumption of steady state periodic solutions of the complete Navier‐Stokes equations. It provides methods of prediction, to a first order of approximation, for the wavelength, celerity, and wave number, in terms of the Weber number which emerges as the governing dimensionless group. This treatment includes as special cases the low Weber number analyses of Yih, Benjamin, Hanratty and Hershman, and Kapitza, as well as the high Weber number theory of Ishihara, Iwagaki, and Iwasa. Agreement with experimental observation is improved over that obtained from previous analyses.The stream function of the system has been derived and the instantaneous streamlines have been constructed for application to heat and mass transfer.
Spinning of a Noll simple fluid
Authors: Slattery John C. 
Published: June 2004

AbstractPrevious results for a class of flows dynamically possible in a Noll simple fluid are the starting point for a description of melt spinning or dry spinning in the limit of a rapidly extruded, small diameter polymer thread. Simultaneous energy and mass transfer, important in the real process, are not taken into account; also neglected are inertial effects, body forces, and surface tension.
A mathematical treatment of the effect of particle size distribution on mass transfer in dispersions
Authors: Gal‐Or Benjamin , Hoelscher H. E. 
Published: June 2004

AbstractA mathematical model is proposed that takes into account interaction between drops or bubbles in a swarm as well as the effect of particle size distribution. The model is used to solve the equations for unsteady state mass transfer with and without chemical reaction when the drops or bubbles are suspended in a nonextraordinarily purified agitated fluid. Steady state diffusion to a family of moving drops with clean interface and without interaction and chemical reaction has been also analyzed. The model demonstrates the sort of error that may arise when one applies uniform drop size assumptions to drop populations. It is shown quantitatively that this error is usually small when one replaces the variable particle size by the mean. By using variables that can be determined and predicted, the equations presented permit the estimation of diffusion rate per unit area of interface, as well as the average concentration and the total average rate of mass transfer in the disperser under pseudo steady state conditions.
Longitudinal dispersion in rotating impeller types of contactors
Authors: Miyauchi Terukatsu , Mitsutake Hiromi , Harase Ichiro 
Published: June 2004

AbstractOn the basis of a back‐flow model, the rates of interstage mixing of continuous phase for RDC and Mixco columns are measured experimentally under flow and nonflow conditions. These rates are correlated into dimensionless formulas for wide combinations of operational condition, column geometry, and dimensions, and are put into a single formula by introducing the power number as an additional parameter. The final correlation covers the impeller Reynolds number from 3.5 × 103 to 1.0 × 106 and the diameter of columns from 4.1 to 218 cm.
A correlation of the frictional characteristics for turbulent flow of dilute viscoelastic non‐Newtonian fluids in pipes
Authors: Meyer Warren A. 
Published: June 2004

AbstractA formula has been determined which satisfactorily represents, for the existing data, the frictional characteristics of the turbulent flow of a dilute viscoelastic non‐Newtonian fluid in a pipe. This formula contains two elastic fluid parameters, one of which is strongly dependent on both polymer solute and concentration and the other appears to be a constant and independent of the polymer solutes which were used in this report. A rheometer is proposed based on this formula which should be useful in classifying fluids of this type.
Investigation of the turbulent shear flow of dilute aqueous CMC solutions
Authors: Ernst William D. 
Published: June 2004

AbstractExperimental measurements of the fully developed turbulent flow field in straight circular tubes of dilute CMC solutions are described. The viscosity of the solutions used had a non‐Newtonian power law exponent of 0.93 to 0.95 in order to eliminate most of the effects attributed to power law fluids. Both pressure drop and velocity profile measurements were made over a wide range of Reynolds numbers. The velocity data were taken in both the linear sublayer and the turbulent core, and are presented in terms of the universal velocity parameters modified by use of a viscosity defined at the tube wall. A check of the existing empirical correlations based on a power law viscosity shows that none predict the observed velocity profiles.
Simultaneous heat and mass transfer in free convection with opposing body forces
Authors: Adams J. A. , McFadden P. W. 
Published: June 2004

AbstractAn experimental technique which utilized a Mach‐Zehnder interferometer was used to measure local heat and mass transfer coefficients during simultaneous heat and mass transfer. The experimental model was a vertical, subliming surface ofp‐dichlorobenzene. The body force created by the heavy organic vapor in the boundary layer opposed the upward thermal body force caused by heating the surface.The results indicated that the heat and mass transfer, under the influence of opposing body forces over the range investigated, was from 10 to 15% lower than the values predicted by present approximate analytical solutions for a constant wall heat flux boundary condition.
The surface transport of adsorbed molecules
Authors: Weaver J. A. , Metzner A. B. 
Published: June 2004

AbstractA detailed mechanistic model is developed to describe the process by which adsorbed molecules migrate over the surface of an adsorbent. The migration is assumed to occur as a result of a random hopping of partially desorbed species; explicit expressions are derived for the hopping rate and the distance traversed in a single jump for the case of a gas adsorbed on a homogeneous surface. In the degree of detail developed herein experimental determinations are still required (to evaluate an otherwise unknown ratio of partition functions, and the activation free energy) but the pressure or surface concentration dependency of the transport rate is given explicity.The predictions are tested by comparison with three sets of experimental data for hydrocarbons adsorbed on porous glass; these systems were chosen as they may be shown to meet the assumption of an adsorbate migrating over an energetically homogeneous surface under the conditions studied. Reasonable values are found for the parameters and excellent agreement between the observed and predicting trends with pressure is noted in all cases.
Entrainment of air into a liquid spray
Authors: Briffa Francis E. J. , Dombrowski Norman 
Published: June 2004

AbstractAn investigation has been carried out into the flow pattern existing in and around a flat spray, particular attention being paid to the region of disintegration of the liquid sheet. The mass of air entrained into the spray, the decay of air velocity along the spray axis, and the spread of the drops in the plane normal to that of the sheet have been related to the operating conditions by equations theoretically derived and experimentally confirmed. Similarities between the characteristics of air entrainment into liquid sprays and into gas jets have been noted.
Generalization of the penetration theory for surface stretch: Application to forming and oscillating drops
Authors: Angelo Jacob B. , Lightfoot Edwin N. , Howard David W. 
Published: June 2004

AbstractA method is developed for predicting rates of mass or heat transfer through stretching or shrinking phase boundaries of finite lifetime at low mass transfer rates. The primary result of this development, Equation (43), may be considered as a generalization of penetration theory. It includes as special cases similar expressions developed for more restricted situations, notably those of Ilkovic (7) and of Beek and Kramers (1).This general development is then used to refine the Rose‐Kintner analysis (13) of mass transfer to large oscillating liquid drops for the limitig case of all heat or mass transfer resistance in the droplet phase. It is found that convection normal to the phase boundary tends to offset the direct effect of surface stretch, and that the postulated mass transfer behavior can be expressed adequately by a very simple expression, Equation (68). This result yields slightly lower predictions of mass transfer rates than the correlation of Rose and Kintner, but available data are not sufficiently accurate to indicate which is the more reliable.The surface‐stretch model is also applied to drop formation at submerged nozzles. Experimentally it was found that the growth of surface during this process is essentially linear, which simplifies calculations. The model gives predictions of the mass transfer coefficient which are in reasonably good agreement with the predictions based on the assumption of continual formation of fresh surface first used by Groothuis and Kramers (18), and later by Beek and Kramers (1). Both models show that the mass transfer coefficient is at least fifteen times as high as predicted by boundary‐layer calculatins alone. Finally, the surface‐stretch model indicates that the mass transfer behavior druing the rise period is approximately fourteen times as important as during the formation period for the equipment used in this study.An expression was also developed for the more general situation of appreciable resistance in each phase, Equation (62), by assuming the surface‐stretch model to describe the transfer processes in both phases. The two‐resistance theory (10) is exact under such circumstances. This result was also found to correlate available data reasonably well.More data, however, are needed if meaningful tests of the above, or other, correlations are desired.
The evaporation of drops of pure liquids at elevated temperatures: Rates of evaporation and wet‐bulb temperatures
Authors: Downingm Carl G. 
Published: June 2004

AbstractThe rates of evaporation and the wet‐bulb temperatures have been correlated for drops of pure liquids evaporating in streams of high‐temperature air. The four liquids studied were acetone, benzene,n‐hexane, and water. The drops were of a millimeter in diameter and were suspended in a free jet of dry, vapor‐free air that ranged in temperature from 27° to 340°C. Reynolds numbers ranged from 24 to 325. Corrections to the Nusselt number to account for the heat lost the outwardly diffusing vapor ranged up to about 35%.
Generalized couette flow of an ellis fluid
Authors: Wadhwa Y. D. 
Published: June 2004

AbstractThe motion of an ordinary Newtonian fluid in a channel caused by a pressure gradient alone, or caused by the motion of one of the walls, can be obtained separately; and the problem of generalized Couette flow (the motion due to both causes simultaneously) can be obtained by superposition. For an Ellis fluid, because of the nonlineraity of the viscosity‐stress law, the principle of superposition is not applicable. This paper is devoted to the solution of this problem of generalized Couette flow of an Ellis fluid in parallel flat plate and circular annular channels.
The effect of monomolecular films on the rate of gas absorption into a quiescent liquid
Authors: Plevan R. E. , Quinn J. A. 
Published: June 2004

AbstractAn experimental technique has been developed for measuring the permeability (or surface resistance) of various monolayers to gases, as well as their effectiveness in hindering any substrate motion which accompanies the absorption process. Results are reported for sulfur dioxide absorbing into water and into aqueous gels in the presence of several surface‐active agents. Measured surface resistances extend from a maximum of 200 sec./cm. for a condensed layer of hexadecanol to an indeterminably small value for expanded and gaseous films. After an initial period in which transfer is by diffusion alone, convective motion sets in. The onset and magnitude of the convective motion is displayed by measured absorption rates into water covered with monomolecular films and into viscous gels. The relative magnitude of the convective retardation of the various films parallels their permeabilities, both effects being proportional to the compressibility of the monolayer.
Laminar dispersion in capillaries: Part III. Experiments in horizontal tubes including observations on natural convection effects
Authors: Reejhsinghani N. S. , Gill William N. , Barduhn Allen J. 
Published: June 2004

AbstractExperimental data on the axial dispersion of a solute in laminar flow in capillaries are presented for a range of Peclet numbers from 12 to 50,000 and of dimensionless time from 0.01 to 60. They show good agreement with the mathematical solutions over all ranges of variables as long as natural convection is unimportant. For slow flows it was observed that natural convection can both enhance and depress the dispersion significantly and that extremely small density differences (Δ p/p = 10−4) are adequate to cause these phenomena. A qualitative explanation for the apparently anomalous effects of natural convection is proposed.
Longitudinal dispersion mechanisms in packed beds
Authors: Babcock R. E. , Green D. W. , Perry R. H. 
Published: June 2004

AbstractA theoretical study has been made of longitudinal dispersion mechanisms during steady flow of a fluid through unconsolidated spherical beads. The mathematical model utilizes a step function input of thermal energy and presents the solution for the transient behvior of the system. The longitudinal dispersion of the step input is considered the result of eddy mixing of the fluid, molecular conduction within the fluid, and a finite time lag for heat transfer to occur between fluid and particle. The latter mechanism is characterized by both a fluid film resistance and an intraparticle resistance. The exact solution, involving an infinite integral, is approximated to an error function form. The character of the contribution of each mechanism is apparent from the form of the approximate solution, and furthermore, the contributions are shown to be additive to yield the total dispersion. The conditions for convergence to the aproximate solution are indicated. The equations are presented such that the analysis is applicable to both heat and mass transfer processes.
Theoretical study of bubble dynamics in purely viscous fluids
Authors: Yang Wen‐Jei , Yeh Hsu‐Chieh 
Published: June 2004

AbstractThis paper analyzes the growth or collapse of a spherical bubble in an incompressible, viscous fluid. Theoretical results include the timewise variations in the bubble size and its growth or collapse rate, the fluid pressure, and the rate of energy dissipation. The analysis is general and may be applied to both Newtonian and non‐Newtonian fluids. A comparison is given for the collapse of the bubble in several viscous fluids.