bluuebunny/crossref_metadata_2025 huggingface dataset:
Multicomponent vapor‐liquid equilibria at high pressures: Part II. Thermodynamic analysis
Authors: Chueh P. L. , Muirbrook N. K. , Prausnitz J. M.
Published: June 2004

Thermodynamic analysis is applied to high‐pressure vapor‐liquid equilibria in binary and multicomponent mixtures containing one or more noncondensable components. A thermodynamic consistency test is described, and a modification of van Laar's model is given for representing adjusted activity coefficients in binary and multicomponent liquid solutions up to the critical composition. With only experimental data used on the two binaries at 0°C., vapor‐liquid equilibria are calculated for the carbon dioxide–nitrogen–oxygen ternary at high pressures. Brief reference is made to the possibility of air separation by high‐pressure absorption in liquid carbon dioxide.
A study of slip ratios for the flow of steam‐water mixtures at high void fractions
Authors: Vance William H. , Moulton R. W.
Published: June 2004

A technique employing the impulse plate principle was developed whereby the ratio of the average vapor‐to‐liquid velocities (slip ratio) for flowing two‐phase mixtures could be measured accurately at high vapor volume fractions. Data were collected for steam‐water mixtures flowing adiabatically in a horizontal ½‐in. tube. Flow conditions were in the spray annular and dispersed flow regimes and covered a pressure range of 30 to 80 lb.f/sq.in.abs., flow rates of 200 to 800 lb.m/(sec.)(sq.ft.), and steam qualities of 0.02 to 0.8. The experimental slip ratios, ranging between 1 and 3.5, decreased with increasing quality and pressure and increased with increasing mass velocity and pressure gradient.

A theoretical analysis in which an idealized dispersed flow model was used indicated that the observed average slip ratios were caused largely by local slip between vapor and entrained droplets and that high local slip ratios may be attained near critical flow rates due to the simultaneously occurring steep pressure gradients.

The total pressure gradients, computed by adding the Martinelli‐Nelson frictional pressure drop prediction to the acceleration pressure gradients calculated by the use of an empirical correlation of the slip ratio data, deviated from the experimental values by an average of only 14%.
The condensing of low pressure steam on vertical rows of horizontal copper and titanium tubes
Authors: Young Edwin H. , Briggs Dale E.
Published: June 2004

Heat transfer data are presented for condensing steam at 2 in. Hg absolute pressure on the outside of nine copper and nine titanium horizontal tubes in a vertical row. The condensing coefficient correction factor was maximum for the top titanium tube and was 46% higher than the correction factor for the top copper tube. The difference between the correction factors for titanium and copper tubes diminished with the number of tubes in a vertical row to 8% higher than the correction factor for copper tubes with six to nine tubes in a vertical row.
Flow and turbulence in a stirred tank
Authors: Cutter Louis A.
Published: June 2004

Photographic measurements have been made of the mean and fluctuating components of velocity of water in a fully baffled stirred tank. Confirmation of much of the photographic data was obtained with a Kiel impact tube. Eulerian correlation coefficients and also Eulerian scales of turbulence were calculated from the photographic data. The Eulerian scale was of the same order as the blade dimensions, a result consistent with earlier measurements on the turbulence behind grids.

Equations have been developed to describe the flow of energy and the conservation of angular momentum in the impeller stream of a stirred tank with a radial flow impeller and vertical baffles. These are simplifications of the Navier‐Stokes equations and the energy equation. They relate energy, angular momentum, and pressure to the mean and fluctuating components of velocity in the impeller stream.

The equations derived are used with the photographic data on mean and fluctuating velocities to estimate the angular momentum at different radial sections of the tank and to calculate the flow of energy through these sections. The estimates are compared with more accurate values of the total torque and energy determined with a torque table.
Enthalpy determinations on the helium‐nitrogen system
Authors: Mage David T. , Katz Donald L.
Published: June 2004

Experimental isobaric heat capacity and differential latent heat measurements have been made on the helium‐nitrogen system. Compositions studied were nominal 5, 25, 50, and 100% helium in nitrogen over the range 0 to 2,000 lb./sq.in.abs. and −250° to 50°F.

These data, combined with the previously reported work on nitrogen and the Joule‐Thomson coefficients of Roebuck, are used to construct the complete pressure‐enthalpy‐composition network over the investigated limits of pressure and temperature.

The enthalpies obtained from experimental heat capacity and Joule‐Thomson data are compared with enthalpies computed from PVT data. The changes of phase determined by differential latent heat measurements are compared with literature vapor‐liquid equilibrium data.

This information is used to prepare pressure‐enthalpy diagrams for all the mixtures investigated. A three‐dimensional representation of the data on a pressure‐enthalpy‐composition diagram is presented. Constructions are outlined from which heats of mixing and partial molal enthalpies can be obtained.

The thermodynamic network developed is believed accurate within 1% and should be of use to those concerned with low‐temperature separation of helium from nitrogen.
Dynamics of a tubular reactor with recycle: Part I. Stability of the steady state
Authors: Reilly M. J. , Schmitz R. A.
Published: June 2004

An analysis of the stability of a plug‐flow tubular reactor with recycle is presented for a model in which axial dispersion of heat and mass is neglected. A method is developed which permits determination of stability or instability for small disturbances immediately upon attainment of the steady state solution. The method, which is applicable to a large class of recycle processes, is based on a Newton‐Raphson iteration technique for steady state solution and on the stability theory of nonlinear difference equations. The feasibility of the method is demonstrated by means of numerical examples which illustrate the occurrence of steady state multiplicity and unstable situations.
The finite‐difference computation of natural convection in a rectangular enclosure
Authors: Wilkes J. O. , Churchill S. W.
Published: June 2004

A study is made of the natural convection of a fluid contained in a long horizontal enclosure of rectangular cross section with one vertical wall heated and the other cooled. Two‐dimensional motion is assumed. The governing vorticity and energy transport equations are solved by an implicit alternating direction finite‐difference method. Transient and steady state isothermals and streamlines are obtained for Grashof numbers up to 100,000 and for height‐to‐width ratios of 1, 2, and 3.
Dynamic characteristics of perforated distillation plates operating at low loads
Authors: Chan B. K. C. , Prince R. G. H.
Published: June 2004

Analysis of the equations describing the instantaneous vapor and liquid flow through the holes of perforated distillation plates at low loads shows that periodic and stable pressure oscillations will always be set up between plates. These oscillations are expected to have amplitudes of the order of 0.1 in. of water and frequencies of a few cycles per second, values which are in accord with observation and which may be used as the basis for a model from which the seal point of the plates may be predicted.
Effects of interfacial instability on film boiling of saturated liquid helium I above a horizontal surface
Authors: Frederking T. H. K. , Wu Y. C. , Clement B. W.
Published: June 2004

Film boiling above a horizontal surface has been investigated theoretically and experimentally at standard gravity and 1 atm. Theoretical film boiling results for conventional fluids have been extended, on the basis of interfacial instability due to gravity, to include liquefied gases properties, such as low viscosity and small surface tension. In the experiments, primarily ordinary liquid helium I has been studied to extend the range of the film boiling Rayleigh numbers (based upon Laplace's reference length) from about 107 (reported for room temperature liquids) to values of the order of magnitude unity. The heat transfer data taken at surface excess temperatures ΔT (above the boiling point) between 80° and 300°K. have been correlated with a theoretical model which presumes the absence of any scaling length (Laplace length) associated with surface tension. At low ΔT the experimental results have been found to agree with a model which presumes a negligible influence of a scaling length due to surface tension and absence of detectable viscosity effects.
Surface motion and gas absorption
Authors: Muenz Kurt , Marchello J. M.
Published: June 2004

The influence of small surface waves on mass transfer from pure gases into water has been investigated. Small amplitude progressive two‐dimensional waves were mechanically generated at the liquid surface for the wave studies. Control experiments with nonwaved surfaces were also conducted. An effective diffusivity was used to correlate the data. Marked increases in mass transfer over that predicted by molecular diffusion for the no‐wave control runs are attributed to natural convection motions, and are probably caused by density and surface tension variations.
Simultaneous axial dispersion and adsorption in a packed bed
Authors: Chao Raul , Hoelscher H. E.
Published: June 2004

A study has been made of simultaneous axial dispersion and solid‐fluid mass exchange in a packed‐bed adsorber. Four different and mutually exclusive controlling mechanisms for the solid‐fluid mass exchange rate are considered. A dimensionless parameter K characterizes this interphase mass transfer. The Peclet number characterizes axial dispersion.

An impulse‐response technique was used to obtain simultaneously values of the axial Peclet number and the rate parameter K in the adsorption column. Values of the Peclet number obtained under conditions of interphase mass transfer were found to be significantly smaller than the values measured under pure mixing (no surface activity) conditions.

The mathematical model used to analyze the results includes the particular case of no surface activity with results previously found from the dispersion model. One result not previously derived from the dispersion model was found and tested experimentally.
An analytical study of laminar counterflow double‐pipe heat exchangers
Authors: Nunge Richard J. , Gill William N.
Published: June 2004

An orthogonal expansion technique for solving a new class of counterflow heat transfer problems is developed and applied to the detailed study of laminar flow concentric tube heat exchangers. The exchanger problem is solved for fully developed laminar velocity profiles, negligible longitudinal conduction in the fluid streams and in the exchanger walls, and with fluid properties which are independent of the temperature.

A description of the variation of the local Nusselt numbers and the temperature at the wall between the two streams is given. Also reported are bulk temperature changes in the two streams and mean overall Nusselt numbers. It is shown that for long exchangers, which are of some industrial importance, asymptotic Nusselt numbers exist in counterflow as in single‐phase and cocurrent systems. Numerical values of asymptotic Nusselt numbers are reported for a wide range of parameters. Comparisons are made with single‐stream solutions such as the Graetz problem, with empirical correlations of experimental data, and with cocurrent flow exchangers.

To solve this problem it was necessary to derive new orthogonality relations, and also expressions for determining positive and negative sets of eigenvalues and eigenvectors. Satisfaction of inlet boundary conditions at both ends of counterflow exchangers requires a complete set of eigenfunctions and thus one must use both the positive and negative sets.
Transmethylation reactions of monomethyl and dimethylamine over montmorillonite in a flow system
Authors: Restelli Edward F. , Coull James
Published: June 2004

In this work the transmethylation reactions of monomethylamine and dimethylamine were investigated under steady state conditions in a flow system. A differential reactor was employed with montmorillonite as the catalyst and the initial rates of these reactions were measured isothermally. Mass velocities through the reactor were sufficiently high to eliminate bulk stream diffusion to the catalyst interface as a possible rate‐controlling step of the reaction process. Pore diffusion was checked experimentally and shown to impose no limit on reaction rates.

The controlling phenomena of the reactions were determined by applying the Freundlich and Langmuir adsorption isotherms to the experimental results in the form of initial reaction rate vs. average partial pressure of reactant at constant temperature. Velocity constants and Arrhenius equations for these controlling processes were also determined.
Accessibility of surface to gases diffusing inside macroporous media
Authors: Hedley W. H. , Lavacot F. J. , Wang S. L. , Armstrong W. P.
Published: June 2004

A method for measuring flow porosity with values from 35 to 100% of the open porosity measured is described. The accuracy of electrical conductivity measurement to obtain net diffusibilities was verified for media containing at least 75% of pore volume with radii greater than five mean free paths. It is pointed out that long dead‐end pores feeding into larger diameter flow pores can contribute to the effective diffusion coefficient inside porous media, and methods of estimating their length and maximum possible contribution to diffusion are described.
Binary physical adsorption of argon and nitrogen on fixed beds of activated silica gel
Authors: Camp David T. , Canjar Lawrence N.
Published: June 2004

The physical adsorption and desorption of argon and nitrogen on fixed beds of 18 × 20 mesh silica gel at −78.5°C. and 1 atm. have been studied. Binary mixtures containing 5.52, 10.34, 51.0, 90.16, 95.13 mole % nitrogen, as well as pure argon and pure nitrogen, were used. Superficial gas velocities were varied from 0.10 to 0.27 ft./sec. Concentration vs. time curves were obtained at bed depths of 5.3, 8.6, and 12.0 in.

Resistance to mass transfer from the gas stream to the outside surface of the particles was found to be negligible. The rate is limited due to mass transfer from the outside surface to the internal surface of the particle. The data were correlated by the integrated Rosen diffusion solution with D = 9.60 (10−8) sq.ft./sec. or alternatively, by the Hiester and Vermeulen integrated model with kp = 0.23 sec.−1.
Bulk flow in diffusion coefficient studies
Authors: Board W. J. , Spalding S. C.
Published: June 2004

The viewpoint is taken that bulk flow terms in the general equation of molecular diffusion must be measured in apparatus which offers no constraint to the molecular flux in either direction. It is proposed to carry this out in a miniaturized experiment operating with one side of the diffusion gradient as an infinite sink. Dimethyl acetamide–water diffusivities computed from such an experiment were found to be 7.02 × 10−6 sq.cm./sec. over a wide range of compositions. These are compared with values showing considerably wider variation with composition, namely, 2.45 to 7.00 × 10−6 sq.cm./sec. by estimating methods and 11.45 to 14.05 × 10−6 sq.cm./sec. by large cell experiments. Arguments are presented in support of the values obtained by the proposed method operating on a nonideal binary N, N‐dimethyl acetamide and water.
Viscosity profiles, discharge rates, pressures, and torques for a rheologically complex fluid in a helical flow
Authors: Savins J. G. , Wallick G. C.
Published: June 2004

Quantitative predictions are presented to show how the axial discharge rate and pressure gradient and angular velocity and torque become coupled when a fluid exhibiting a shear‐dependent viscosity behavior is subjected to a helical flow field. The numerical scheme developed here is completely general and applicable to a wide choice of constitutive equations. For purposes of illustration only, results are described for an Oldroyd type of constitutive equation. The coupling effect is illustrated for different relative speeds of the cylinders, axial flow rates, axial pressure gradients, and ratios of cylinder diameters. The most interesting consequence of the coupling effect is that the axial flow resistance is lowered in a helical flow with the result, for example, that for a given applied axial pressure gradient, the axial discharge rate in a helical flow field is higher than in a purely annular flow field.
Performance of fouled catalyst pellets
Authors: Masamune Shinobu , Smith J. M.
Published: June 2004

Equations are developed for the bulk rate of a gaseous reaction on a porous catalyst whose activity changes with time due to a decrease in active surface. The performance is evaluated in terms of a pellet effectiveness factor which is a function of time and a Thiele (diffusion‐reaction) modulus. By a stepwise numerical technique, the equations can be solved without resort to assumptions regarding the distribution of fouled surface within the pellet. The method is applicable at isothermal conditions for any form of the rate equations for the main and fouling reactions and for any diffusivity‐concentration relationship.

To illustrate the method, results are given for first‐order isothermal reactions for three types of fouling processes. For a series form of self‐fouling, a catalyst with the lowest intraparticle diffusion resistance gives the maximum activity for any process time. In contrast, for parallel self‐fouling a catalyst with an intermediate diffusion resistance is less easily deactivated and can give a higher conversion to desirable product, particularly at long process times.

A simpler solution is possible by supposing that the shell model represents the disposition of fouling material in the pellet. It is shown that for parallel self‐fouling and independent fouling this model gives reasonably good results, even when the reaction resistance for the main reaction is important. However, the shell concept does not appear suitable over a range of conditions when the fouling is of the series type.

The single‐pellet effectiveness factors can be used to determine the effect of fouling on the conversion in a fixed‐bed reactor. To illustrate the method of approach curves of conversion as a function of time and position in the bed are presented for a parallel, self‐fouling reaction system. The results show the influence of intraparticle diffusion on the overall effects of fouling.
The viscosity of liquid metals
Authors: Chapman Thomas W.
Published: June 2004

In order to make the kinetic theory of liquid viscosity tractable, an approximate from is suggested for the perturbation of the radial distribution function of a monatomic liquid by a nonuniform flow field. Substitution of this form into the microscopic expression for the pressure tensor yields an equation for liquid viscosity in terms of the equilibrium distribution function and the interatomic potential energy function. This equation establishes the basis for a corresponding states correlation of the viscosity of liquid metals based on atomic parameters.

The viscosity data for twenty‐one molten metals are made to fall on a single curve by the adjustment of one microscopic parameter. It is found that this empirically determined parameter has the proper fundamental significance. Therefore it is possible to estimate it independently and to use the general correlation for estimating the viscosity of a metal for which data are not available. Also it is suggested that the atomic parameters determined from viscosity data in this way might be used to correlate other properties of the liquid metals.
Stability of falling liquid films. Effect of interface and interfacial mass transport
Authors: Whitaker Stephen , Jones L. O.
Published: June 2004

Previous studies of the effect of surface active agents on the stability of falling liquid films indicated that surface elasticity was primarily responsible for the observed stabilizing action. Since the elastic nature of a surface is thought to be controlled by interface and interfacial mass transport, it is of interest to understand how these transport rates affect the stability of the liquid film. The analysis for both soluble and insoluble surface active agents is presented in terms of a perturbation solution of the Orr‐Sommerfeld equation.
Experimental vapor‐liquid equilibrium data for propane‐isobutane
Authors: Hipkin Howard
Published: June 2004

Isothermal vapor‐liquid equilibrium data for propane‐isobutane, a system of industrial importance, have been obtained in two pieces of apparatus at temperatures from 20° to 250°F. Over this temperature range, propane‐isobutane form ideal solutions. The paper discusses the sampling errors which occur in volatile systems.
Ion exchange equilibria under pressure
Authors: Hamann S. D. , McCay I. W.
Published: June 2004

Previous work on the ionization equilibria of weak acids and bases at high pressures suggested that compression should favor the transfer of protons from a weakly acidic resin to a weakly basic one in a mixed bed system, and that the resulting increase of ionization should extract cations and anions from the surrounding solution. In agreement with this idea it has now been observed that the equilibrium concentration of a solution of sodium chloride around a mixture of De‐Acidite M and Zeo‐Karb 226 resins is almost halved when the pressure is raised from 1 to 3,000 atm. The change is completely reversible.

The measurements indicate that the proton transfer process involves a contraction of about 15 cc. mole−1, which is remarkably close to the analogous contraction [15 to 18 cc. mole−1] that occurs when a proton is transferred from a free carboxylic acid to an amine in solution.
An experimental study of falling liquid films
Authors: Jones L. O. , Whitaker Stephen
Published: June 2004

A new method for measuring wavelength and wave velocity is described, and experimental values for water flowing down a vertical plane are compared with a numerical solution of the Orr‐Sommerfeld equation. Good agreement is obtained in the region near the top of the film where small disturbance theory is expected to be valid. Experimental Reynolds numbers ranged from 8 to 120.
Effects of product recycle and temperature on autocatalytic reactions
Authors: Ahn Yong‐Kee , Fan Liang‐Tseng , Erickson Larry E.
Published: June 2004

The effect of product recycle and temperature on the maximum yield of product for several different autocatalytic reactions taking place in a tubular reactor is studied.

A generalized version of the maximum principle is used to determine the maximum conversion and optimal temperature profile for each of the reactions considered. The fraction of product recycled, which affects the concentration of autocatalytic agent entering the reactor, is investigated to determine its effect on the maximum conversion.
Diffusion of gases in electrolytic solutions
Authors: Gubbins Keith E. , Bhatia Kamlesh K. , Walker Robert D.
Published: June 2004

Measurements of the diffusion coefficients of hydrogen and methane in strong aqueous electrolytes have been made with the use of the diaphragm cell method. The variation of the diffusion coefficients with electrolyte concentration, type of ion, and temperature has been studied over the electrolyte concentration range zero to saturated, and for temperatures in the range 25° to 65°C.

The results have been interpreted with the Eyring rate theory. The presence of ions in water increases the activation energy for diffusion which results in a decrease in the diffusion coefficient. The increase in activation energy is represented by terms that are additive for the ions involved. The influence of ions on the diffusion coefficient increases rapidly with ionic charge, but seems to be little affected by temperature or solute for the systems studied.
Heat transport and temperature distributions in large single drops at low Reynolds numbers: A new experimental technique
Authors: Head Harlan N. , Hellums J. D.
Published: June 2004

A new experimental technique has been developed for study of transport from drops. Large single drops are heated dielectrically while suspended motionless in an unheated continuous phase. Direct measurements of temperature distributions within drops are presented both for circulating drops and for drops in which surface‐active materials retard circulation. The results of the measurements will be useful in assessing the validity of the various proposed models.
Application of the Wohl equation to ternary liquid‐vapor equilibria
Authors: Adler Stanley B. , Friend Leo , Pigford Robert L.
Published: June 2004

The use of the Wohl equation for activity coefficients is tested successfully for the most nonideal ternary systems for which experimental data could be found. The three‐suffix form possessing seven constants is found to be successful in many cases. Owing to the high degree of nonideality resulting from one or more components being polar, however, the four‐suffix form employing up to ten constants was required for ten of the twenty‐five ternaries studied. Regardless of the form chosen, all the constants but one, C*, are derived from phase equilibrium data on the constituent binaries.

The ternary constant C* was found to be approximately zero. In only two instances did its value not fall in the region of −1.0 to +1.0. With the use of the binary constants and C*, predictions of vapor compositions were made for each experimental ternary liquid composition, temperature, and pressure. The results so obtained yielded average absolute errors in predicted vapor mole fractions, without respect to sign, as follows: for ten systems, less than 0.01; for seventeen systems, less than 0.02; and for twenty‐four systems, less than 0.03. For an additional three sets the error was still less than 0.05. Results were analyzed statistically for twenty‐two of the systems determining mean values of the vapor mole fraction deviations and the confidence limits of the means.

The mass testing of the Wohl equation reported here far exceeds the sum of all work previously published in the literature. It appears that this equation provides a very good way of expressing liquid nonideality for a wide range of components.
Uniform flux heat transfer to a gas in laminar forced convection in a circular tube
Authors: Bergman Perry D. , Koppel Lowell B.
Published: June 2004

Heat transfer from a circular tube to a contained gas in laminar forced convection was studied dimensionally and experimentally. The boundary condition of uniform heat flux was physically achieved, and the experiments were conducted in a statistically designed pattern. The dimensional analysis, based upon the principle of corresponding states, and more general than any hitherto proposed, indicated four independent variables in this experiment. Of these, only bulk velocity showed a statistically significant effect in the region studied: a reduction in heat transfer coefficient with decreasing bulk velocity. No existing theories could explain this effect.
Stability of autorefrigerated chemical reactors
Authors: Luyben William L.
Published: June 2004

Stability of exothermic chemical reactors with cooling jackets or internal cooling coils has been extensively studied by steady state, phase plane, and linear analysis techniques. The purpose of this paper is to apply these techniques to the frequently encountered case of autorefrigerated or boiling liquid reactors. In these reactors the exothermic heat of reaction is removed, not by conductive and convective heat transfer, but by vaporization of a liquid phase or, more generally, by any kind of endothermic change in phase.

Open‐loop and closed‐loop stability of a continuous stirre‐tank autorefrigerated reactor is studied. General equations are derived and illustrated by numerical examples.

Both constant and variable latent heats of vaporization are considered. A particularly interesting aspect of autorefrigerated reactor stability is operation near the critical temperature. Since the latent heat approaches zero, instability of the system is increased, representing a form of positive feedback in a chemical system.
Newtonian jet stability
Authors: Grant Rollin Peter , Middleman Stanley
Published: June 2004

Although Newtonian jet stability has been the object of numerous experimental and theoretical studies, the total problem of jet disintegration is by no means solved. Theories available in the literature are only applicable to low‐speed laminar jets in stagnant air. In practice, the stability of a liquid jet may be influenced by the ambient medium, turbulence in the nozzle, and the extent of development of the velocity profile. None of these factors has received adequate study. This work presents the beginning of a systematic evaluation of the role played by these factors in the destabilization of a liquid jet. Correlations are presented for predicting the stability of both turbulent and high‐speed laminar jets in stagnant air.
Phase equilibria in polymer solutions
Authors: Heil J. F. , Prausnitz J. M.
Published: June 2004

A new semiempirical equation is presented for the Gibbs energy of mixing for solutions of polymers in single and mixed solvents. The equation contains two adjustable parameters per binary mixture and can readily be extended to multicomponent systems without additional parameters. The new expression gives a very good representation of the properties of a variety of polymer solutions including those in which there are strong specific interactions such as hydrogen bonding. Parameters are determined from binary vapor pressure data.

A graphical method based on the new equation is given for predicting solubility limits in ternary systems containing one polymer and a mixed solvent. Only binary data are used. The method is demonstrated by comparisons of predicted solubility behavior with new experimental data taken on systems composed of polystyrene and the following mixed solvents: acetone‐toluene, acetone‐benzene, methanol‐benzene, methanol‐ethyl acetate, and acetone‐methylcyclo‐hexane.
Reaction of chlorine and uranium tetrachloride in the fused lithium chloride‐potassium chloride eutectic
Authors: Olander Donald R. , Camahort J. L.
Published: June 2004

The rates of the reaction of chlorine gas with uranium tetrachloride dissolved in the lithium chloride‐potassium chloride eutectic have been studied in a wetted‐rod contactor. The reaction was studied at temperatures from 400° to 700°C., uranium tetrachloride concentrations of 1 to 3 wt. %, and chlorine partial pressures of 0.25 to 1 atm. The production of uranium hexachloride appears to be limited by the equilibrium of the reaction UCL4 (solution) + Cl2 (g) = UCl6 (solution) at the interface and by U+4 diffusion in the liquid phase.
Similarity solutions for non‐Newtonian fluids
Authors: Lee S. Y. , Ames W. F.
Published: June 2004

Similarity transformations are possible for power law fluids in the following systems: momentum transfer in general Falkner‐Skan flows and Goldstein flows; and momentum and energy transfer in forced convection about a right angle wedge, natural convection with constant heat flux at the boundary surface, and general Falkner‐Skan flows with nonconstant heat conductivity and a restricted boundary temperature distribution. Similarity transformations are also possible for momentum and heat transfer of Eyring viscous fluids about a right angle wedge. A numerical solution is obtained for forced convection of power law fluids about a right angle wedge with an isothermal surface. From the numerical results an approximate expression is obtained for the local Nusselt number.
Laminar‐Turbulent transition for nonisothermal pipe flow
Authors: Scheele George F. , Greene Howard L.
Published: June 2004

Finite disturbance pipe flow stability criteria are evaluated for constant flux heating of liquids flowing through vertical pipes under small disturbances conditions where velocity profile distortion due to natural convection is significat. For Newtonian flow in long heated pipes the analysis of Hanks correctly predicts the transition to turbulence observed for upflow heating and is qualitatively consistent with the transition to asymmetric flow which occurs in downflow heating, whereas the criterion of Ryan and Johnson predicts stability for experimentally unstable flows. In the practically more important case of short pipe lengths experimental data obtained over the viscosity range from 1 to 21 centiposises show that natural convection induced transition will occur at low Reynolds numbers for both Newtonian and non‐Newtonian liquids for conditions consistent with predictions of Hanks' analysis.
The incipience of nucleate boiling in forced convection flow
Authors: Davis E. J. , Anderson G. H.
Published: June 2004

An analysis of the incipience of nucleate boiling is developed as a modification and extension of previous analyses. The results are compared with data for subcooled boiling of water in forced convection flow. Apparent anomalies in the data for the onset of boiling in two‐phase gas‐liquid flow are shown to be a result of a limited size range of cavities on the heater surfaces. Measurements of the surface characteristics of a copper heating tube were made and compared with incipient boiling heat transfer data taken in that tube. The results predicted from the theoretical analysis are consistent with the experimental heat transfer data.
Vapor‐Liquid equilibria for five cryogenic mixtures
Authors: Sprow F. B. , Prausnitz J. M.
Published: June 2004

Phase equilibrium data have been obtained for the binary systems nitrogen‐argon and nitrogen‐carbon monoxide at 83.82°K. and for the systems nitrogen‐methane, argon‐methane, and carbon monoxide‐methane at 9.67°K. Total pressures and compositions of both phases were measured. Parameters have been calculated for the Redlich‐Kister and Wilson equations for the excess Gibbs energies of the mixtures. The data are thermodynamically consistent within experimental error.
Shape of liquid drops moving in liquid media
Authors: Wellek R. M. , Agrawal A. K. , Skelland A. H. P.
Published: June 2004

An investigation of the effects of various physical properties, drop size, and drop velocity on drop shape was carried out for nonoscillating liquid drops falling through stationary liquid continuous phases. The data of forty‐five dispersed‐continuous phase systems were studied with continuous phase viscosities varying from 0.3 to 46 centipoise and interfacial tensions varying from 0.3 to 42 dyne/cm. A theoretical relation was obtained from the Taylor and Acrivos analysis which quite accurately predicts drop eccentricities for drop Reynolds numbers less than about 20, but is highly inaccurate at higher Reynolds numbers. Relatively simple empirical relations involving the Weber number, Eötvös number, and viscosity ratio were obtained which enable the prediction of the eccentricity of nonoscillating drops over a wide range of Reynolds numbers (6.0 to 1,354) with average deviations of 6 to 8%. These relations may be useful in the estimation of the interfacial area, velocity, and continuous phase mass transfer coefficient of drops distorted from spherical shape.
Laminar dispersion in capillaries: Part II. Effect of inlet boundary conditions and turner type of system capacitance
Authors: Gill William N. , Ananthakrishnan V.
Published: June 2004

The effect of inlet boundary conditions on the transient approach to the asymptotic Taylor‐Aris theory was studied for three different cases. It was found that for values of τ of practical interest the solutions for these cases were different only if NPe < 100. The asymptotic solution was independent of inlet conditions in the three cases studied once τ exceeded the necessary minima.

A rather complete numerical solution to the equation that describes laminar flow in tubes with a single continuous stagnant pocket of arbitrary depth along the entire length of the pore has been obtained, and results for point, average, and bulk concentration distributions are presented for a wide range of parameters. The range of applicability is extended to infinity for both τ and NPe by the asymptotic theory of Aris.

Higher capacitance systems require longer times before their dispersion behavior can be described by error‐function solutions. This is important, since only then is the concept of an equivalent axial dispersion coefficient useful because then it allows the calculation of the complete average concentration distribution from a minimum of data. This suggests that in work on high capacitance systems such as packed beds, one should ensure that experimental systems are long enough for the asymptotic theory to apply if results are to be interpreted in terms of dispersion coefficients.

Numerical results for the Turner model agree very well with the modified effective dispersion coefficient, which was suggested by Aris and is given in Equation (15), as long as τ is sufficiently large. These lower limits for τ are given in Table 3. When the lower limits on τ are exceeded, the new solution developed for the point distribution given by Equations (31) and (32) is also valid. This is important for at least two reasons. First, it implies that the dispersion model can be used to describe the local as well as the average behavior of complex transient systems if only the velocity distribution across the system is known. More work is needed to ascertain the limitations and possibilities of the dispersion model in this regard. Second, it shows that one can find simple and accurate approximate local solutions without neglecting axial molecular diffusion.
Viscosities of methane and propane at low temperatures and high pressures
Authors: Huang E. T. S. , Swift G. W. , Kurata Fred
Published: June 2004

The viscosities of methane and propane were determined at pressures to 5,000 lb./sq. in. abs. over a temperature range from −170° to 0°C. and −100° to 0°C., respectively, and the densities of propane were measured at pressures to 5,000 lb./sq. in. abs. over the temperature range from −100° to 0°C. Reproducibility of the viscosity data was about ± 1.2% and for the most part agreement with literature values was within ± 2%. the estimated accuracy of the density measurement was ± 0.5%. The data reported were well correlated in terms of residual viscosity vs. density.
Theoretical study of fluid flow accompanied by solid precipitation in porous media
Authors: Kuo Chiang‐Hai , Closmann Philip J.
Published: June 2004

This paper deals with compressible fluid flow accompanied by solid deposition in a porous reservoir. The isothermal fluid flow is considered to be radial and follows Darcy's law. The initially dissolved substances precipitate from the solution as a result of solubility reduction as the pressure declines. These deposits accumulate in the void spaces and hence inhibit the flow. An idealized model describing this transport mechanism has been proposed. On the basis of this model, a numerical technique has been developed to predict the amount of solid precipitation and the pressure distribution as functions of time and radial distance.

The method is applied to the production performance of a reservoir containing mainly hydrogen sulfide saturated with elemental sulfur. The solid sulfur builds up rapidly in the vicinity of the production well. A very negligible amount is formed close to the impermeable outer boundary. It is shown that plugging by solid sulfur in the porous medium can be reduced either by reducing the production rate or by choosing closer well spacing.
Coalescence in fibrous beds
Authors: Sareen S. S. , Rose P. M. , Gudesen R. C. , Kintner R. C.
Published: June 2004

The factors affecting the efficacy of a closely packed bed of mixed cotton and a supporting fiber (Teflon, glass, Dynel) were evaluated for oil‐in‐water dispersions. Several other water‐organic systems were also tested. Superficial velocities ranged from 0.2 to 3.5 ft./min. Successful coalescence was attained at interfacial tensions as low as 3.5 dynes/cm. Dispersed phase viscosity was varied form 1.4 to 137 centipoise. For a mixed‐fiber bed with a specific ratio of fiber species, there is an optimum bed depth for best performance. High‐speed cinephotomicrographic observations at 100 × and up to 4,000 frames/sec. indicated that fiber wettability is not the most important factor for successful operation.
Transport properties of a dense fluid of molecules interacting with a square‐well potential: Part II
Authors: Luks K. D. , Miller M. A. , Ted Davis H.
Published: June 2004

The equations developed by Davis, Rice, and Sengers for the transport properties of a model fluid whose molecules interact according to a square‐well potential are utilized herein to calculate the transport coefficients of krypton, xenon, and argon. With the use of theoretically determined pair correlation functions and experimental P‐V‐T data, results are obtained that indicate that the square‐well theory provides a useful model for simple liquids. Master graphs of the transport coefficients as functions of reduced parameters are presented. An investigation of the relative importance of the contributions by kinetic transfer and by intermolecular collisional transfer leads to the conclusion that kinetic transfer can provide a sizable contribution to transport properties.
Diffusion and solution of gases in thermally softened or molten polymers: Part I. Development of technique and determination of data
Authors: Durrill Preston L. , Griskey Richard G.
Published: June 2004

A technique has been developed that determines simultaneously solubilities and diffusivities of gases in molten or thermally softened polymers. Henry's law was found to hold up to 20 atm. In addition it was found that pressure had no appreciable effect on diffusion coefficients up to 20 atm. Solubilities and diffusivities were determined for systems involving nitrogen, helium, carbon dioxide, and argon in polyethylene, polyisobutylene, and polypropylene. In addition, solubilities were also determined for the preceding gases in polystyrene and polymethylmethacrylate. Other data were also obtained for neon, krypton, and monochlorodiflouromethane in various polymers.
Some aspects of crystallization theory: Systems that violate McCabe's delta L law
Authors: Canning T. F. , Randolph A. D.
Published: June 2004

A new empirical model has been proposed to described crystallization systems where the growth rate increases with increasing crystal size in violation of McCabe's ΔL law. Experimental data for Glauber's salt have been presented to illustrate the fit of the new model to an actual system. Equations for steady state crystal size distributions with the use of the proposed model have been derived. Wider use of population density plots for analysis of crystallization systems along with the coefficient of variation to describe a distribution numerically is recommended.
Interfacial turbulence during the absorption of carbon dioxide into monoethanolamine
Authors: Brian P. L. T. , Vivian J. E. , Matiatos D. C.
Published: June 2004

Severe discrepancies exist between theoretical considerations and the carbon dioxide–monoethanolamine absorption data available in the literature. By desorbing the inert tracer propylene simultaneously with the absorption of carbon dioxide into monoethanolamine in a short wetted‐wall column, it is shown that the physical mass transfer coefficient is increased substantially by the carbon dioxide–monoethanolamine chemical absorption process. This is presumably due to interfacial turbulence driven by surface tension gradients. The use of the actual physical mass transfer coefficient prevailing during carbon dioxide absorption into monoethanolamine results in a considerable improvement in the agreement between the penetration theory solution and the experimental data on the rate of absorption of carbon dioxide into monoethanolamine.
Isothermal homogeneous two‐phase flow in horizontal pipes
Authors: Huey C. T. , Bryant R. A. A.
Published: June 2004

In the first part of this paper a theory for isothermal homogeneous two‐phase, liquid‐gas flow in horizontal pipes is established by introducing the concept of Mach number and by considering the medium to be a pseudo gas. The theory takes account of wall friction, compressibility and flow choking. A set of working formulas is obtained. In the second part, results of experiments on homogeneous bubbly flows of water‐air mixtures in a 1‐in. Pipe are reported. Criteria for the occurrence of bubbly flow are established and the occurrence of flow choking confirmed. It is shown that the mathematical model is adequate insofar as it explains, phenomenologically, real flow conditions.
The control of nonlinear systems. Part II: Convergence by combined first and second variations
Authors: Luus Rein , Lapidus Leon
Published: June 2004

It is shown that the first variation method can be used to provide an excellent starting condition for the second variation control of nonlinear systems. Numerical examples illustrate the basic features of the methods.
The control of nonlinear systems. Part III: Invariant imbedding and quasilinearization
Authors: Rothenberger B. F. , Lapidus Leon
Published: June 2004

An iterative technique is proposed that solves the two‐point boundary value problem formed from the variational equations for the optimal control of nonlinear systems. The computational algorithm utilizes invariant imbedding to provide a set of the unknown boundary conditions and quasilinearization to calculate the optimal control policy. A numerical example indicates that the method exhibits considerable promise.
Flow of molten polymers through porous media
Authors: Gregory Dale R. , Griskey Richard G.
Published: June 2004

The flow of molten polymer through porous media has been investigated at constant temperatures and flow rates. Temperatures of 375°, 400°, and 425°F., flow rates from 12 to 60 g./min. and particle sizes from 0.054 in. to 6 mm. in diameter were studied. A modified Darcy's law was developed using the Metzner‐Reed modification of the Mooney‐Rabinowitsch relation. This form was then used to develop a modified friction factor plot which correlated the data with an average error of 5.02%. Calculated superficial velocities from the Darcy's law equation checked experimental values generally to within 10%. A technique for estimating shear rates when curved rheological flow curves occurred was also developed.