bluuebunny/crossref_metadata_2025 huggingface dataset:
Power requirements of gas‐liquid agitated systems
Authors: Michel B. J. , Miller S. A.
Published: June 2004

Power data for dispersion of air in liquids by means of a six‐bladed flat blade turbine are presented in the form of a logarithmic plot of actual power consumed against a function of speed, impeller diameter, gas flow rate, and impeller power characteristics. The data are those of Michel (7), Bimbenet (2), Sachs (12), and Oyama and Endoh (10).

Turbines of from 3‐ to 8‐in. diameter were run in tanks of from 6.5‐ to 18‐in. diameter, with the D/T never exceeding 0.47. The fluids tested covered a density range of 0.8 to 1.65 g./ml. and a viscosity range of 0.9 to 100 centipoises.

Data are also presented on dispersion of air in a 50% by volume batch of carbon tetrachloride in water and dispersion of air in a suspension of Alundum particles in water, and compared with data on water in a similar system.

The qualitative effect of a surface active agent is demonstrated in a comparison of data for a 0.1% by weight mixture of Pluronic L‐62 in water with data for pure water with the same apparatus.
Mass transfer and effective interfacial areas in packed columns
Authors: Yoshida Fumitake , Koyanagi Tetsushi
Published: June 2004

Experimental studies on the mass transfer rates were performed for three kinds of operations: vaporization of water into air; absorption of methanol vapor by water; and distillation of three binary mixtures, trichloroethylene‐toluene, ethanol‐water, and acetone‐water, by use of columns of the same diameter packed with 25‐ and 15‐mm. Raschig rings. Correlations are presented for the individual phase height of a transfer unit and also for the effective interfacial areas. The effective areas for a given packing vary depending on the kind of operation as well as on the liquid rate and surface tension. The effective interfacial area for vaporization is significantly larger than that for absorption. The effective area for distillation seems to be roughly the same as that for absorption, if correction is made for the effect of surface tension.
Heat transfer in beds of fine particles (heat transfer perpendicular to flow)
Authors: Willhite G. P. , Kunii Daizo , Smith J. M.
Published: June 2004

Effective thermal conductivites were evaluated for beds of fine glass beads from experimental data on heat transfer perpendicular to the direction of fluid flow. Results were obtained for a bead size range of 29 to 940 μ and for carbon dioxide, nitrogen, helium, and a C7 hydrocarbon liquid.

The results showed that over the range of flow rate studied 0 to 80 lb./(hr.sq.ft.), or modified Reynolds number from 0 to 6.6, there was no effect of flow on the conductivity. Hence the measured stagnant conductivity k°e also satisfactorily represented heat transfer for flowing conditions. In view of this result, methods of predicting the stagnant conductivity were re‐examined and a revised prediction method proposed. The equations are based upon a model which supposes energy to be transferred through a continuous fluid phase and through the solid particles by a solid‐fluid series mechanism. The equations are compared with the data available in the literature.
Diffusion in slurries and in non‐Newtonian fluids
Authors: Clough S. B. , Read H. E. , Metzner A. B. , Behn V. C.
Published: June 2004

Diffusivities in slurries and in non‐Newtonian solutions are predicted by means of an extension of the general Eyring rate theory. The fluid is considered as consisting of a number of discrete regions, each with its own contribution to the overall diffusion process. This model overcomes the unrealistic effects of fluid viscosity predicted by the conventional (empirical) equations. Whereas diffusivities predicted by means of prior art correlations were as much as 230 times lower than the experimental values in the systems, the maximum error in diffusivities predicted with the equations developed in this work was about 40%.

Experimental data are provided on two kinds of fluids: slurries and a polymer solution. Both were highly non‐Newtonian (flow behavior indexes as low at 0.15). Benzoic acid and β napthol were employed as the diffusing solutes. The principal limitation of the experimental data is that only aqueous systems were investigated.

Much further experimental work will be required to provide a truly adequate test of the theory and to evaluate the several unknown parameters in sufficient detail to enable highly accurate predictions. Additionally the model used suggests a possible mechanism for increasing diffusion rates in these systems which is worthy of exploration. It may also be applied to an analysis and prediction of diffusion rates in viscous Newtonian fluids, for which no adequate method is presently available.
Void fraction distribution in beds of spheres
Authors: Benenati R. F. , Brosilow C. B.
Published: June 2004

The radial variation of void fraction within a packed bed of uniform spheres has been found to vary from unity at the wall to about 38% in the interior of large beds. The voidage distribution takes the form of a damped oscillatory wave with the oscillations damped out at about 4½ to 5 sphere diameters from the container wall. The distribution function is essentially independent of whether the container wall is concave or convex.

Continuous surfaces within the bed are responsible for local voidage variations similar to those at the container wall.

An improved experimental technique is described in detail. The results presented are for a number of cases with D/d varying from 2.6 to infinity, and for boundary walls which are concave and convex.
Transport characteristics of suspensions: Part VI. Minimum transport velocity for large particle size suspensions in round horizontal pipes
Authors: Thomas David G.
Published: June 2004

The minimum transport velocity (defined as the mean‐stream velocity required to prevent the accumulation of a layer of stationary or sliding particles on the bottom of a horizontal conduit) vas determined in a 1‐in. pipe for an aqueous suspension of glass beads using glass beads having mean diameters of 78 and 310 μ.

The results of the present study were combined with prior pneumatic‐ and hydraulic‐transport data for air and water suspensions to give a unique minimum‐transport relation, valid for particles larger than the thickness of the laminar sublayer, that is for particles which are immersed in the buffer layer or which extend into the turbulent core when resting on the pipe wall. The correlation showed that the ratio of particle settling velocity to friction velocity at the minimum transport condition was a function of particle Reynolds number, pipe Reynolds number, and the relative density ratio of particle to fluid. The results of the correlation suggest that a single mechanism is responsible for the initiation of particle transport throughout the range of conditions covered. This mechanism may be identified with Bernoulli forces due to instantaneous velocity differences accompanying turbulent fluctuations and largely confined to the buffer layer.
The role of porosity in filtration: Part V. Porosity variation in filter cakes
Authors: Tiller F. M. , Cooper Harrison
Published: June 2004

Expressions are derived in which local porosity in a filter cake is determined as a function of the distance through the cake. Under conditions where the superficial flow rate through the cake is constant and the medium pressure can be neglected, local porosity and the hydraulic pressure are functions of the fractional cake distance.
Low temperature ortho‐para hydrogen conversion‐kinetic studies
Authors: Wakao Noriaki , Selwood P. W. , Smith J. M.
Published: June 2004

Rate studies were carried out for the ortho‐para hydrogen conversion at liquid nitrogen temperature with a multiple‐impregnation nickel on aluminum oxide catalyst. Data were obtained at pressures up to 400 lb./sq. in. gauge over a range of flow rates for three catalysts of different pellet sizes.

For the largest particle, ⅛‐in. cylinders, diffusion resistances were significant. Effectiveness factors were evaluated and found to be somewhat less that 0.5 for this relatively active catalyst. After the diffusion resistances were accounted for, the surface rate was correlated on the basis of a mechanism supposing molecular hyddrogen to be adsorbed on the surface. Separate evaluation of the catalyst for the hydrogen‐deuterium exchange reaction suggested that dissociation was not significant at liquid nitrogen temperature.
High temperature transport properties of gases; limitations of current calculating methods in the light of recent experimental data
Authors: Amdur I.
Published: June 2004

Requirements for satisfactory calculation of high temperature transport properties are discussed, with special emphasis on the role of the intermolecular potential. The determination of appropriate pair potentials from scattering of high energy neutral beams is described, and potentials obtained from helium, neon, argon, krypton, and xenon, each scattered by its own gas, are tabulated. Similar potentials are given for helium scattered by argon, nitrogen, methane, monofluoromethane, difluoromethane, trifluoromethane, and tetrafluoromethane; neon by argon; argon by hydrogen and nitrogen; atomic hydrogen by helium and hydrogen; and atomic deuterium by deuterium gas. Average potentials derived from suitable combinations of these experimental potentials are given for the like‐particle systems of nitrogen, methane, monofluoromethane, difluoromethane, trifluoromethane, and tetrafluoromethane.

Results of calculations which use suitable and unsuitable potential functions are shown in tabulated form for the coefficient of viscosity, the coefficient of self‐duffusion, and the isotopic reduced thermal diffusion ratio of argon and of nitrogen, and in graphical form for the coefficient of viscosity of xenon.
Solid‐liquid‐vapor phase behavior of the methane‐carbon dioxide system
Authors: Davis J. A. , Rodewald Newell , Kurata Fred
Published: June 2004

The phase behavior of the methane‐carbon dioxide system has been determined experimentally along the solid‐liquid‐vapor locus. Pressure‐temperature measurements were made along this locus from the triple point of carbon dioxide to −284°F. Compositions of the vapor phase along the solid‐liquid‐vapor locus were determined with sampling techniques over a composition range of 0.1 to 12% carbon dioxide. Liquid‐phase compositions were obtained from crystal‐point determinations on eleven methane‐carbon dioxide mixtures ranging from 0.16 to 20% carbon dioxide.

With the pressure‐temperature for the solid‐liquid‐vapor locus as the termination locus of the dew and bubble data of Donnelly and Katz (2), consistent liquid‐ and vapor‐phase compositions were obtained over the remaining concentration range.

Changes in the pressure‐temperature relationship of the solid‐liquid‐vapor locus caused by using a methane stock containing 0.56 mole % nitrogen are also reported.
Transfer functions of heat exchangers
Authors: Hsu James P. , Gilbert Nathan
Published: June 2004

In the course of research the authors have collected a number of transfer functions for various types of heat exchangers. For the convenience of analysis the heat exchangers may be classified into several basic types described in subsequent pages. In each case certain assumptions are made when one writes down the differential equations of the heat exchanger, which constitute the so‐called mathematical model of the exchanger. If a particular heat exchanger is being classified, it is important to know the nature of temperature variation and the relative directions of flow of the exchanging fluid streams. If the heat exchanger in question matches one of the types described, then the transfer functions listed may be used to obtain its theoretical frequency and transient responses.
The prediction of vapor‐liquid equilibrium constants for binary hydrocarbon systems in the critical region
Authors: Mehra Vinod S. , Thodos George
Published: June 2004

A series of reduced state correlations for the prediction of equilibrium constants for the components of binary hydrocarbon systems have been developed utilizing experimental vapor‐liquid equilibrium data reported by Kay (7, 8, 9) for the enthane‐n‐heptane, ethane‐n‐butane, and n‐butane‐n‐hepane systems. Each correlation applies for a specific values of τ = Tbh/Tbl, the ratio of the normal boiling points of the two components. Plots of β/β° vs. TR covering the complete range of liquid compositions are presented for values of τ = 1.10, 1.20, 1.40, 1.60, 1.80, and 2.00. The term β° represents the reduced vapor pressure of the pure substance, while β is the ratio of the pseudo vapor pressure of this substance in the mixture, Kπ, to the critical pressure of the mixture.

The correlations presented in this study reproduce the experimental data used in their development with an average deviation of 2.3% for forty‐eight points, with the experimental critical constants reported by Kay. The reliability of these correlations has been tested with the propane‐isopentane, methane‐ethane, and ethane‐cyclohexane systems which have τ values in the range included in this study and for which experimental critical constants are available. An average deviation of 5.1% was produced for thirty‐six points. In addition the systems methane‐propane, propane‐benzene, nitrogen‐oxygen, and carbon dioxide‐n‐butane were tested with calculated values for their critical constants and produced average deviations of 8.4, 8.2, 9.4, and 20%, respectively.
Reaction kinetics and adsorption equilibria in the vapor‐phase dehydration of ethanol
Authors: Kabel Robert L. , Johanson Lennart N.
Published: June 2004

This work is an experimental assessment of the Langmuir‐Hinshelwood model of heterogeneous catalysis. The vapor‐phase dehydration of ethanol to diethyl ether, as catalyzed by cation exchange resin in the acid form, was the reaction chosen for study.

Initial reaction rate data, determined from the integral kinetic data obtained experimentally, allowed selection of the most suitable rate equation from among several plausible equations derived in accordance with the above model. The Langmuir equilibrium adsorption constants in the rate equation were compared with the corresponding constants determined directly from pure component studies in a static adsorption system. The adsorption constants determined for the three reacting components by these independent methods showed definite order‐of‐magnitude agreement. The adsorption studies also provided significant information about the nature of the catalytic site.

The extent of agreement in the constants determined by these two independent approaches is considered to be evidence of the theoretical validity of this model. Additional interpretation of the adsorption and kinetic data via this model suggests that the ethanol dehydration reaction proceeds through the reaction of adjacently adsorbed ethanol molecules.
Radiant heat transfer in packed beds
Authors: Chen John C. , Churchill Stuart W.
Published: June 2004

The effective scattering and absorption cross sections were determined from measurements of radiant transmission through isothermal beds of glass, aluminum oxide, steel and silicon carbide spheres, cylinders, and irregular grains. The radiant conductivities were calculated from these cross sections. Back scattering was found to be the principal mechanism of attenuation for all of the packings. Absorption was a significant mechanism only for the silicon carbide grains. At 2,000°F. The radiant contribution to the total heat flux was estimated to vary from 35% for the silicon carbide packings to 85% for the glass packings.
Ion exchange equilibria in a ternary system
Authors: Pieroni Leonard J. , Dranoff Joshua S.
Published: June 2004

A study has been made of the cation exchange equilibria between Dowex 50W‐X8 resin and aqueous solutions of copper nitrate, nitric acid, and sodium nitrate in binary and ternary mixtures. Experiments were carried out at room temperature with solutions having total cation concentrations of approximately 0.1N, 0.05N, and 0.01N. It was found that the equilibria for any two ions were essentially the same in binary and ternary mixtures. Moreover single valued selectivity coefficients were determined which characterize these data quite well for all three concentration levels. This makes possible the complete description, for engineering purposes, of ternary equilibria in terms of the simpler and more accessible binary exchange reactions, as previously suggested (1).
High‐flux heat transfer characteristics of pure ethylene glycol in axial and swirl flow
Authors: Gambill W. R. , Bundy R. D.
Published: June 2004

Measurements were made of heat transfer rates and peak heat flux for atmospheric‐pressure pool boiling, and of adiabatic and diabatic friction factors, nonboiling and local‐boiling heat transfer rates, and burnout heat fluxes for both axial‐ and twisted‐tape swirl‐flow forced convection of pure ethylene glycol. Test sections were electrically heated copper, 347 stainless steel, and A‐nickel tubes.

Both axial‐ and swirl‐flow friction factors are in good agreement with available generalized correlations. At the higher Reynolds numbers and heat fluxes axial‐flow nonboiling heat transfer coefficients show a dependence of Nusselt number onNRe0.98rather than the traditionalNRe0.80. Swirl‐flow nonboling heat transfer coefficients from both the glycol data and previously obtained water data are satisfactorily correlated by a single equation. Nucleate‐boiling heat transfer coefficients for both ethylene glycol and water fall approximately 50% above Kutateladze's suggested average line. The atmospheric‐pressure pool‐boiling peak flux is 168,000 Btu/hr. sq. ft. Forced‐convection burnout heat fluxes are correlated in a number of ways, including a new additive method which appears to be generally applicable to a large variety of coolants, geometries, and flow conditions.
High‐pressure phase‐equilibrium studies by gas‐liquid partition chromatography
Authors: Stalkup Fred I. , Kobayashi Riki
Published: June 2004

An elution gas that might be either a single component or a binary mixture, but which in any case was appreciably soluble in the fixed liquid phase on the column matrix material, was used to form a multicomponent liquid phase within the chromatographic column. Vapor‐liquid equilibrium was studied both with the solute of interest at essentially infinite dilution conditions and with the solute present at some finite concentration in both phases. From the elution data vapor‐liquid equilibrium ratios, or K values, were calculated by expressions relating the solute retention volume to the solute K value in the vapor‐liquid system maintained within the chromatographic column.

Data were taken for the solutes ethane, propane, and n‐butane at infinite dilution in the methane‐n‐decane system at 160°, 70°, 40°, 0°, and −20°F from 20 to 2,000 lb./sq. in.; for propane at infinite dilution in methane‐n‐hexadecane at 70°F and 20 to 200 lb./sq. in.; and propane in the system methane‐propane‐n‐decane at 40°F from 20 to 460 lb./sq. in. The univariant gas‐liquid‐solid locus was experimentally determined for the methane‐n‐decane binary system.

The chromatographically determined K values for n‐butane at infinite dilution in methane‐n‐decane were compared with published static equilibrium values and found to be in substantial agreement. Activity coefficients calculated from the data for all the solute isotherms were compared at atmospheric pressure with the results of the Brönsted and Koefoed relation for estimating activity coefficients of hydrocarbons, and close agreement was again found.
Dynamics of liquid‐solid fluidized bed expansion
Authors: Fan Liang‐Tseng , Schmitz James A. , Miller Eugene N.
Published: June 2004

The dynamic response of height in liquid‐solid fluidized beds to a change in fluidizing valocity was considered. A linearized model was developed such that the time constant for the system could be estimated with the parameters characterizing the system.

Spherical particles, with sizes ranging from 6 to 7 to 70 to 80 mesh and densities ranging from 1.08 g./cc. to 2.5 g./cc., were fluidized by water in a 2‐in. diameter glass column. The experimental response to step and rectangular pulse inputs in fluidizing velocity were measured and frequency response data were also obtained.

Agreement between the experimental data and the model was quite reasonable in view of the known nonlinearity of fluidization systems. These results show that for control purposes the system behaves as a first order time constant process.
An experimental study of the unsteady nature of the viscous sublayer
Authors: Reiss L. Philip , Hanratty Thomas J.
Published: June 2004

Measurements of the fluctuations in the mass transfer rate to small circular electrodes mounted flush with a pipe wall are used to study the unsteady nature of the viscous sublayer. These fluctuations in the mass transfer rate reflect flow fluctuations at y+ ca 0.5. From these measurements it is concluded that the flow disturbances are elongated in the direction of flow and are characterized by a time scale equal to the diameter of the pipe divided by the bulk average velocity. An attempt is made to relate the mass transfer fluctuations to the fluctuation in velocity gradient at the wall. It is concluded that the ratio of the root‐mean‐square fluctuating velocity gradient at the wall to the average velocity gradient at the wall is at least 0.11.
Eddy transport in liquid‐metal heat transfer
Authors: Dwyer O. E.
Published: June 2004

There are certain semiempirical equations for estimating heat transfer coefficients for liquid metals flowing through regular shapes. These contain the factorψ, which is the average, effective value of the ratio of the eddy diffusivity of heat transfer to that for momentum transfer. The main problem in liquid metal heat transfer has been to evaluate this quantity.
Fluid flow and convective‐radiative energy transfer in a parallel‐plate channel under free‐molecule conditions
Authors: Sparrow E. M. , Jonsson V. K.
Published: June 2004

The flow of a highly rarefied gas in a parallel‐plate channel and the transfer of heat owing to simulataneous thermal radiation and free‐molecule convection has been investigated analytically. The analysis is facilitated by analogies which exist between the processes. The mass throughflow has been determined as a function of the temperatures and pressures of the system and of the channel dimensions. The heat transfer analysis is first carried out in general and then specialized to the boundary conditions of uniform wall temperature, uniform wall heat flux, and the adiabatic wall. It was found that at temperature levels corresponding to room temperature and above, the results for the combined convective‐radiative transport differed little from those for a purely radiative transport.
Mass transfer in the laminar radial wall jet
Authors: Scholtz M. T. , Trass Olev
Published: June 2004

Data are reported for mass transfer from a flat plate under the influence of a laminar, radial wall jet initiated by a free jet of water.

Present theory has been extended to mass transfer for the case of the above wall jet. An exact solution of the mass transport equation was obtained as well as an approximate solution of the integral mass balance equation, using assumed forms of the velocity and concentration profiles.

Point mass transfer data were obtained by measuring the thickness decrease of coatings of acetanilide and benzoic acid. In the Reynolds number range of 1,000 to 3,000 (based on the nozzle diameter) data were in good agreement with theory. Boundary‐layer separation and the formation of a toroidal vortex were observed at lower Reynolds numbers. Dye streak photographs of these vortices were obtained and correlated with mass transfer data in this region.
Pulsation in a fixed‐bed reactor
Authors: Biskis E. G. , Smith J. M.
Published: June 2004

Rates of reaction were measured for the liquid phase hydrogenation of α‐methyl styrene in a pulsed, fixed bed reactor. Data at 80 psia and 55°C., using 0.5 wt. % palladium on ⅛″ Al2O3spheres as a catalyst, indicated that the mass transfer of dissolved hydrogen to the catalyst surface controlled the rate of conversion of styrene to cumene. Hence the data were employed to calculate mass transfer coefficients as a function of pulse frequency and amplitude.

Comparison with non‐pulse data at the same Reynolds number showed that pulsation increased the mass transfer rate as much as 80%.
Heat transfer in the critical region—temperature and velocity profiles in turbulent flow
Authors: Wood Rodney D. , Smith J. M.
Published: June 2004

Unusual heat transfer phenomena have been observed between solid surfaces and fluids near their thermodynamic critical point. To understand better these phenomena temperature and velocity profiles and local heat transfer coefficients were measured for turbulent flow of carbon dioxide in a tube at 1,075 lb/sq. in. abs. (pc= 1,071). The results indicate a severe flattening of the radial temperature profiles, a maximum in the velocity profile between the wall and the tube axis, and a maximum inh' when the bulk fluid temperature passes through the transposed critical temperature.

The results can be explained qualitatively by considering the variation with temperature of thermal conductivity near the tube wall and specific heat in the turbulent core.
Diffusion and reaction in porous glass
Authors: Rao M. Raja , Smith J. M.
Published: June 2004

Constant pressure diffusion rates of hydrogen through Vycor porous glass were measured in nitrogen and neon systems. The experimental diffusivities are less than those predicted by the random pore model indicating that this model may not be satisfactory for a low porosity material such as Vycor. Interpreted in terms of an assembly of parallel pores the data suggest a tortuosity factor of approximately 2.4.

Rate data for the ortho‐para hydrogen reaction were also measured at −196°C. and 1 atm. The catalyst 2% nickel/Vycor was found to have pore properties (area, mean pore size, pore volume) similar to that of plain Vycor. Predicted effectiveness factors using the experimental diffusion data were in good agreement with values determined experimentally. The latter were evaluated from rate measurements on both pellet and particles (58 μ mean diameter).
Solution of the linearized equations of multicomponent mass transfer: I
Authors: Toor H. L.
Published: June 2004

The linearized equations of diffusion in a multicomponent system with flow and chemical reaction are shown to reduce to a set of equivalent binary diffusion equations.

The concentrations and fluxes in a multicomponent system are described by linear combinations of appropriate solutions to the binary diffusion equation for steady and unsteady diffusion and convective mass transfer, laminar or turbulent.

The rate of transfer of each component in a nonreacting n component system is a linear combination of the n‐1 independent driving forces with proportionality constants which depend upon the multicomponent diffusion coefficients and appropriate binary mass transfer coefficients, while the concentration profile of each component is a linear combination of appropriate binary concentration profiles with proportionality constants which depend upon the multicomponent diffusion coefficients and the characteristic displacement from equilibrium of each component.

The linearized theory is exact for small changes in concentration but needs further testing when the concentration changes and fluxes are large.
Resistance to mass transfer inside droplets
Authors: Skelland A. H. P. , Wellek R. M.
Published: June 2004

An experimental investigation of the effects of various physical properties on the dispersedphase mass transfer coefficient was carried out for both nonoscillating and oscillating liquid droplets falling in a single stream through stationary continuous liquid phases. The Colburn and Welsh two‐component technique was used to isolate and measure the disperesed‐phase resistance to mass transfer. This technique limited the experimental study to systems with low interfacial tensions, between 2.5 and 5.8 dynes/cm. Solute was transferred into the droplets, and the droplet concentration was measured after droplet‐fall heights ranging from about 2 cm. to 103 cm. Precautions were taken to minimize end effects.

The experimental mass transfer rates on nonoscillating droplets in general were greater than that predicted by the Kronig and Brink model for nonoscillating circulating droplets. Experimental Sherwood numbers for four liquid systems were correlated in terms of a relationship involving the dispersed‐phase Schmidt number, the Weber number, and the time group, 4DLtc/d2e, which allows for the time dependency of the transfer mechanism. The data were correlated with an average absolute deviation of 34%. The Kronig and Brink and Newman relations fitted the experimental data for nonoscillating droplets with an average absolute deviation of 46 and 54%, respectively. The experimental results for the oscillating droplets were correlated by two relationships with an average absolute deviation of 10.5%. The Handlos and Baron model fitted the experimental results for oscillating droplets with an average absolute deviation of 38%.
Kinetics of hydrogen reduction of ferrous oxide in a batch fluidized bed: Effects of mass velocity and pressure
Authors: Ahner W. D. , Feinman Jerome
Published: June 2004

The kinetics of reduction of ferrous oxide with hydrogen were studied in a 1½‐in. diameter isothermal batch fluidized reactor. The effects of mass velocity and pressure on the reduction path were investigated over the ranges 5.3 to 19.2 moles/sq.ft.hr. and 1.3 to 5.4 atm. at 1,000° and 1,300°F. The results are correlated by means of instantaneous oxygen balances on the assumptions that there are no oxygen concentration gradients in the solid phase, that the distribution of residence times for the gas flow is represented closely by assuming complete mixing, and that the reduction rate is controlled at the oxide‐metal interface. The rate of reduction increased with increasing pressure and mass velocity. An excellent correlation was obtained for the program at 1,000°F. At 1,300°F. sintering and grain growth of the product layer complicated the reduction process, and a correlation was not obtained. Application of the results to the design of commercial fluidized‐reduction processes is discussed qualitatively.
Thermodynamics and interfacial tension of multicomponent liquid‐liquid interfaces
Authors: Shain Stephen A. , Prausnitz J. M.
Published: June 2004

Sternling and Scriven have shown that the derivative of interfacial tension with respect to solute concentration is an important parameter influencing the hydrodynamic stability at an interface across which mass transfer is taking place. This work is concerned with a molecular thermodynamic study of that derivative.

With surface thermodynamics and an extension of the solution theory of Schuchowitzky, an expression is derived which relates the interfacial tension to the solute concentration in terms of physically meaningful parameters. These in turn are related to molecular properties of the solute and solvent species.

New experimental data are reported for the interfacial tension of nine ternary systems; these consist of an aqueous phase and an organic phase where both phases are dilute solutions of an alcohol. The organic phases are hexane, benzene, and carbon tetrachloride and the alcohols are methanol, ethanol, and n‐propanol.

The theoretical equations predict interfacial tensions which are in good agreement with the new experimental results and with experimental data of Vignes on aqueous‐organic systems which are dilute solutions of organic acids.
Formation of air bubbles at orifices submerged beneath liquids
Authors: Sullivan S. L. , Hardy B. W. , Holland C. D.
Published: June 2004

The results of two investigations are reported. Air bubbles were formed at orifices submerged beneath each of fourteen liquids. The surface tension of the liquids varied from 17.8 to 72.4 dynes/cm., and the viscosities ranged from 0.436 to 713 centipoise. In the first investigation, air bubbles were formed at orifices at various angles of inclihation. Orifice diameters ranging from 0.159 to 0.396 cm. were employed. The air‐flow rate was varied from 0.1 to 100 cc. (at standard conditions)/sec. The results were obtained with two different apparatuses by three independent investigators.

In the second investigation, the effect of the velocity of a liquid flowing past a horizontal, submerged orifice on the formation of air bubbles was determined. Liquid velocities ranging from 0.34 to 2.5 cm/sec., which spanned the region of laminar flow, were employed. Orifice diameters ranged from 0.15875 to 0.3175 cm., air‐flow rates from 0.5 to 100 cc/sec. (at standard conditions).

It was found that the bubble formation observed in each of these investigations could be correlated with the physical variables of the system by the application of Newton's second law of motion to the bubble at the instant just prior to its release from the orifice.
Tube flow of non‐Newtonian polymer solutions: PART I. Laminar flow and rheological models
Authors: Meter Donald M. , Bird R. Byron
Published: June 2004

A correlation of turbulent tube‐flow friction factors for non‐Newtonian polymer solutions, based upon the fluid property τ1/2; defined in Part I, has been found to represent data taken on seven solutions of Natrosol hydroxyethylcellulose in ½‐ and 1‐in, I.D. smooth tubes, with an average accuracy of 10.8%. Also, for these seven solutions, this correlation gives somewhat more accurate predictions of the point of transition into turbulent flow than are made by the Ryan‐Johnson stability theory.

The correlation must be considered only provisional, however, because it does not simplify to the limiting case of extremely dilute solutions. Plausible extensions based on models of steady‐flow non‐Newtonian viscosity behavior, and other possible correlation schemes utilizing viscoelastic fluid properties, are briefly discussed.
Effective binary diffusion coefficients in mixed solvents
Authors: Tang Y. P. , Himmelblau D. M.
Published: June 2004

The diffusion of carbon dioxide through ethanol‐water, benzene toluene, and carbon tetrachloride benzene was studied over the entire range of compositions for the solvent pairs. The results were interpreted in terms of an effective binary diffusion coefficient. Two semiempirical correlations were derived with the aid of absolute reaction rate theory to predict the effective binary diffusion coefficient from the binary diffusion coefficients of the solute in the individual pure solvents. These equations, although only crude approximations, reproduced the experimental data for six diffusion systems fairly well, including the highly nonideal solvent mixture ethanol‐water.
Film boiling of nitrogen with suction on an electrically heated porous plate
Authors: Wayner P. C. , Bankoff S. G.
Published: June 2004

Experimental equipment to study the film boiling of liquid nitrogen on a porous heat source with vapor suction was developed. The electrically heated element was a 3.69 in. sintered stainless steel screen, which was also used as a resistance thermometer in conjunction with an a.c. potentiometric circuit. In preliminary work, this mode of heat transfer was unstable, but stability was achieved by placing a porous flow control element on the liquid side of the heater. It was found that the Nusselt number was a function of only the Reynolds number; the heat transfer coefficient was increased by a factor of as much as 2.5 over the heat transfer coefficient in normal film boiling; it was possible to vary independently any two of the three variables, heat flux, flow rate through the plate, and temperature difference; and the generated vapor was considerably superheated. Fluctuations in the local surface temperature were measured in film boiling from both porous and nonporous flat plates, indicating that momentary solid‐liquid contacts can occur, for all practical purposes, in film boiling.
Liquid atomization in a high intensity sound field
Authors: Wilcox R. L. , Tate R. W.
Published: June 2004

High intensity sound was investigates as a means for liquid breakup. Sonic generators provided energy to atomize liquid introduced near the sound source. Droplet size was measured at several conditions of air and liquid flow for sound intensities ranging up to 160 decibels.

Atomization was good at low liquid flows but became rahter coarse as flow rate increased. The droplet size distributions were not uniform. No improvement in breakup could be attributed directly to the sonic compressions and rarefactions beyond that normally produced by the tearing action of air in conventional two‐fluid atomizers at comparable air/liquid ratios.
Thermal conductivity of porous catalysts
Authors: Butt John B.
Published: June 2004

A random pore model of catalytic pore structure is applied to the determination of the thermal conductivity of porous catalytic solids. The low thermal conductivities reported for such materials are explained by considering the microporous particles to consist of a packed bedlike assembly of smaller particles; heat transfer through the solid fraction occurs by conduction through individual small particles in contact with other particles. An expression for the effective thermal conductivity of a gas in the region between ordinary thermal conduction and free molecule conduction is used in determination of heat conduction through the void volume. Agreement of the theory with experimental data on alumina and silver catalysts over a wide range of conditions is good.
Thermodynamics of mixed‐gas adsorption
Authors: Myers A. L. , Prausnitz J. M.
Published: June 2004

A simple technique is described for calculating the adsorption equilibria for components in a gaseous mixture, using only data for the pure‐component adsorption equilibria at the same temperature and on the same adsorbent. The proposed technique is based on the concept of an ideal adsorbed solution and, using classical surface thermodynamics, an expression analogous to Raoult's law is obtained. The essential idea of the calculation lies in the recognition that in an ideal solution the partial pressure of an adsorbed component is given by the product of its mole fraction in the adsorbed phase and the pressure which it would exert as a pure adsorbed component at the same temperature and spreading pressure as those of the mixture. Predicted isotherms give excellent agreement with experimental data for methane‐ethane and ethylene‐carbon dioxide on activated carbon and for carbon monoxide‐oxygen and propane‐propylene on silica gel. The simplicity of the calculation, which requires no data for the mixture, makes it especially useful for engineering applications.
Lateral transport in a fluidized‐packed bed: Part I. Solids mixing
Authors: Gabor John D.
Published: June 2004

A theory was developed to relate the average velocity of a fluidized particle to the fluidizing gas velocity and the minimum fluidization velocity. The development of this relationship was based on a model for particle movement caused by gas bubbles rising through the fluidized bed. The diffusivity for lateral solids mixing in a fluidized‐packed bed can then be determined from the average particle velocity and the diameter of the fixed packing by the random walk theory.
Lateral transport in a fluidized‐packed bed: Part II. Heat transfer
Authors: Gabor John D. , Stangeland Bruce E. , Mecham William J.
Published: June 2004

Effective thermal conductivities for lateral heat transfer were measured in a fluidized‐packed bed. An analysis of the mechanism of heat transfer was made by comparison with previously determined rates of solids mixing. A general correlation was made of the fluidized‐packed bed thermal diffusivities with the size of the fixed packing and the minimum fluidization velocity in a manner similar to the correlation for lateral solids mixing diffusivities in a fludizied‐packed bed.
Analysis of phase‐boundary motion in diffusion‐controlled processes: Part I. Solution of the diffusion equation with a moving boundary
Authors: Griffin J. R. , Coughanowr D. R.
Published: June 2004

Three general methods are developed for solving moving‐boundary problems which are governed by diffusional processes such as heat and mass transfer. Examples of such problems include melting, evaporation, and ablation. A method based upon a Riemann‐Volterra integration of the diffusion equation leads to nonlinear integrodifferential equations for the boundary motion that are in terms of definite integrals involving Green's functions. An analytical method, which is more convenient for problems involving phase motion, is based on the method of intermediate integrals. A numerical method based on finite difference approximations is implemented on the differential analyzer (analogue computer).
The thermal conductivity and diffusivity of gases for temperatures to 10,000°K
Authors: Mathur G. P. , Thodos George
Published: June 2004

A generalized method has been developed for the prediction of the diffusivity and thermal conductivity of nonpolar gases for temperatures up to 10,000°K. This method is applicable to monatomic gases and to diatomic gases existing in their molecular and dissociated states. Dimensional analysis has been used to obtain relationships for self‐ and mutual diffusivities and for the translational contribution to the thermal conductivity of these substances. For the internal contribution to thermal conductivity, a modified Eucken‐factor relationship is presented. Furthermore, relationships have been developed for the calculation of these transport properties for the equilibrium mixture of a dissociating gas.
The friction factor–Reynolds number relation for the steady flow of pseudoplastic fluids through rectangular ducts. Part I. Theory
Authors: Wheeler John A. , Wissler Eugene H.
Published: June 2004

A finite difference technique is used to calculate the velocity profile, maximum shear stress, and friction factor‐Reynolds number product for a power‐law, pseudoplastic fluid flowing through a cylindrical duct of rectangular cross section. It is assumed that the motion is rectilinear. A very simple friction factor‐Reynolds number correlation is obtained for the special case of a square duct.
Mixing of viscous non‐Newtonian fluids in packed beds
Authors: Hassell H. L. , Bondi Arnold
Published: June 2004

Radial mixing of concentrated solutions of rubber dissolved in a light aliphatic hydrocarbon was studied in beds packed with glass spheres or York mats. The degree of mixing in the bed of spheres was significantly better, that is the Peclet number much smaller, than predicted from Wilhelm's correlation.

Pressure drop associated with the flow of rubber cement through packed beds is well represented by existing correlations, provided the effective viscosity is obtained from a shear rate vs. shear stress diagram for the fluid.
Generalization of gas‐liquid partition chromatography to study high pressure vapor‐liquid equilibria of multicomponent systems
Authors: Koonce K. Terry , Deans H. A. , Kobayashi Riki
Published: June 2004

The use of chromatographic retention volume data to obtain vapor‐liquid equilibrium coefficients has been extended to a ternary system with all components present at finite concentrations in the liquid phase and essentially a light binary gas comprising the vapor phase. The data are obtained by observing the retention time of the solute of interest when that solute is eluted by a flowing gas stream through a column packed with an inert porous firebrick on which is impregnated a fixed, relatively nonvolatile liquid. The retention times are used to compute retention volumes which may be related to the K values of the solute.

A previous mathematical description of the elution process is modified to include the case of an N component elution gas, all constituents of which are soluble in the fixed liquid phase. A general solution is derived for the multicomponent elution gas from which K values for each component may be calculated if retention volume data are taken for each, provided molecules of the solute samples used are distinguishable from others of the same species present in the eloution gas. For the case of indistinguishable sample molecules, the rate theory development of Stalkup and Deans is verified for a binary elution gas.

Sufficient retention data were taken to completely define the concentration dependence of the K value for propane in the system methane‐propane‐n‐decane at −20°, 0°, 40°, and 70°F. from 20 to 1,000 lb/sq.in.abs. Six methane‐propane binary mixtures were used as elution gases, consisting of 2.08, 4.31, 6.90, 9.44, 13.09, 16.27 mole % propane. Retention data were also taken for methane under the same conditions. Distinguishability of sample molecules was achieved by using radioactive solute samples tagged with carbon‐14.

Propane retention data were also obtained for the system methane‐propane‐n‐heptane at −20° and −40°F. from 100 to 1,000 lb./sq.in.abs. for propane at infinite dilution and for binary elution gases composed of 2.08 mole % propane at −40°F. and 4.31 mole % propane at −20°F.

All K values determined chromatographically were either compared directly with published static equilibrium values or tested for consistency with such values and found to be in substantial agreement.
Film instabilities in two‐phase flows
Authors: Ostrach Simon , Koestel Alfred
Published: June 2004

The major types of instabilities which can alter a given two‐phase flow pattern or lead to the breakup of a liquid film are delineated, and their physical mechanisms are discussed. Existing stability criteria are correlated to these basic types, and their application and limitations with respect to actual problems are indicated. Basic areas requiring further study are outlined.

A criterion for determining the breakup length of a liquid film is developed which gives an indication of whether a given instability will lead to low frequency and high amplitude pressure and inventory pulsations. Such phenomena may be undesirable.

Two new aspects of importance to the problem of film instability are introduced which have not been previously studied. These are rotation of the fluids and large disturbances in the flow. Their possible influence on the problem is discussed.
Effectiveness factors for general reaction rate forms
Authors: Bischoff Kenneth B.
Published: June 2004

The great utility of the effectiveness factor concept to account for intraparticle diffusion lies in its simplicity of application. Unfortunately, the standard formulation leads to a separate relationship for each type of reaction rate form, which greatly complicates practical computations.

A general asymptotic solution is given here which leads to the definition of a general modulus somewhat different in form from the standard one. The use of this general modulus tends to approximately bring together all of the various curves.

To illustrate its use, a few new exact solutions for simple order reactions are derived and combined with existing solutions for both simple order and adsorption reaction rate forms. It is seen that all of the curves lie within a relatively narrow range. Thus the general modulus permits one to estimate the effectiveness factor for any arbitrary reaction from the existing curves.