bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vapor condensation in the mixing zone of a jet
Authors: Hidy George M. , Friedlander S. K. 
Published: June 2004

AbstractExperimental studies were made of fog formation in free jets containing glycerine and dibutyl phthalate. Visual and photographic observations showed that condensation took place near the nozzle in the mixing zone between the jet and the ambient air. Fog formation began at a well‐defined location downstream from the nozzle depending on the initial velocity, temperature, and concentration of vapor. The location could be changed by inserting solid bodies or by adding foreign nuclei to the mixing zone. Measurements were made of mean temperature and concentration profiles in the mixing zone with noncondensable gases. These compared well with the predictions of turbulent boundary‐layer theory. Calculations were made of the supersaturation to be expected in the case of glycerine. Downstream of the point where condensation first occurred fog filled most of the region where the calculated supersaturation was above unity. Based on the experimental evidence a mechanism is proposed for condensation in a free jet.
Adsorption rate studies—significance of pore diffusion
Authors: Masamune Shinobu , Smith J. M. 
Published: June 2004

AbstractAdsorption rates were measured by a transcient method for nitrogen on beds of porous Vycor glass particles. Nitrogen was adsorbed, from a low concentration in helium, at liquid nitrogen temperature.Equations are presented for the concentration as a function of time and position in the bed, based upon surface adsorption, pore diffusion, or external diffusion controlling the overall process. Analysis of the data with these results indicates that the surface adsorption is a very rapid process and that pore processes determine the rate for particles larger than 0.01 cm. in radius. The effective pore diffusivity was determined to be 0.04 sq. cm./sec. The predominant contribution to the diffusivity is a surface mechanism rather than diffusion in the gas within the pores.
A numerical method for the solution of the energy equation for steady turbulent heat transfer
Authors: Strunk Mailand R. , Tao Frank F. 
Published: June 2004

AbstractA method is presented for solving the basic energy expression for the temperature distribution for turbulent heat transfer in a circular conduit with a digital computer. The method assumes a knowledge of the velocity distribution, the eddy conductivity term as a function of the radial position, and a constant wall temperature. For illustrative purposes only a dimensionless expression is derived from Reichardt's relationship which gives the eddy conductivity term as a function of radial position with Reynolds and Prandtl numbers as parameters.Incorporated in the computer program is Richardson's three‐point extrapolation formula which permits the determination of a more accurate eigenvalue from three previously computed values which were obtained by using three different values of the reduced radial increment. Agreement with the Crank‐Nicholson method is quite good, although the method with eigenvalues is considered to be superior. Eigenvalues determined from the analytical solution of the energy expression for the laminar flow case and those computed by the numerical method are in excellent agreement. This is indicative of the accuracy and reliability of the proposed numerical method.
A model building technique for chemical engineering kinetics
Authors: Hunter William G. , Mezaki Reiji 
Published: June 2004

AbstractThe object of much experimentation is to build or discover a suitable model for a given system. Unfortunately very little work has been published on what constitutes good strategies in these situations. This paper is an attempt to formulate an approach to this important problem of iteratively improving models in the area of chemical engineering kinetics. In this technique a statistical analysis is applied to the estimated parameters of a tentatively entertained theroretical model in such a way as to pinpoint its inadequacies, if they exist, so that it is possible to proceed in a logical manner to an appropriate modification of this model. This modified model is then analyzed in a similar way, and further modifications are suggested. In general the cycle is repeated as often as is necessary to reach an adequate model. This sequential method is illustrated by finding an adequate reaction model for the total catalytic oxidation of methane.
Continuous foam fractionation: The effect of operating variables on separation
Authors: Grieves R. B. , Wood R. K. 
Published: June 2004

AbstractContinuous foam fractionation has a great deal of promise as a chemical engineering separation technique; however more information is needed concerning the effect of operating variables upon the separation which may be obtained. An experimental investigation is presented of the influence of temperature, of liquid residence time, and of the position of feed introduction upon the foam fractionation of the ethylhexadecyldimethylammonium bromide‐water system. The study involves three series of experiments and ninety foam separation runs. For a given air rate and feed stream concentration and rate, the drain stream concentration and rate increase linearly with temperature and the foam concentration and enrichment ratio are increasing functions of temperature. Equations derived from a multiple linear regression analysis enable the calculation of the drain stream concentration and rate from the feed concentration, air rate, and temperature.Based upon experiments involving the variation in liquid residence time by two methods, changes in solution height have no influence upon the separation, indicating the rapid achievement of equilibrium. Changes in feed rate and air rate show that the volume of air employed per unit volume of feed treated is a prime variable affecting the separation.Positioning the feed inlet at the solution‐foam interface, compared with feeding into the solution, provides a significant increase in drain rate and decrease in drain concentration. Moving the feeder higher into the column of foam results in a continued decrease in drain concentration, but in the passage of the drain rate and foam concentration through maximum values at a height corresponding to approximately the midpoint of the column of foam.
Solution of the linearized equations of multicomponent mass transfer: II. Matrix methods
Authors: Toor H. L. 
Published: June 2004

AbstractSolutions to the equations of multicomponent mass transfer may be written as matrix generalizations of the solution to the equivalent binary mass transfer equation when intial and boundary concentrations are constant, there are no homogeneous reactions, and all physical properties including the diffusion coefficient matrix are concentration independent.The analogue of the binary mass transfer coefficient is a multicomponent mass transfer coefficient matrix which depends only upon the mass transfer coefficients of the equivalent binary system and the diffusion coefficient matrix of the multicomponent system.When interphase transfer takes place, the inverse multicomponent mass transfer coefficient matrices of each phase are additive. Their sum yields an overall resistance to mass transfer which is the inverse of the overall multicomponent mass transfer coefficient matrix.
Effects of reduced gravity on nucleate boiling bubble dynamics in saturated water
Authors: Siegel R. , Keshock E. G. 
Published: June 2004

AbstractA study was made of nucleate boiling bubble dynamics in saturated distilled water for various reduced gravity fields. The nucleation occurred on a very smooth horizontal nickel surface at low heat fluxes. Since because of the smooth surface finish only a few nucleation sites were active, it was possible to photograph individual bubbles that were not interfered with by adjacent bubble columns. Data were taken at seven different gravity fields in the range from 1.4 to 100% of earth gravity by placing the apparatus on a counterwieghted falling platform. Measurements were made of bubble departure diameters and frequencies, growth rates, contact angles, base circle diameters, and rise velocities. Comparisons were made to determine whether the measured gravity dependence of these quantities was in agreement with that predicted by correlations in the literature.
Turbulent disruption of flocs in small particle size suspensions
Authors: Thomas David G. 
Published: June 2004

AbstractIn the absence of turbulent fluctuations the main effect of a velocity gradient on the floc properties is a rearrangement of particles within the floc producing a more dense floc structure. When the suspension is sufficiently dilute that floc‐floc collisions are negligible, the limits on the floc diameter are (1 + α)5/3 < (Df/Dp) ⩽ (1 + α)2, where α is the ratio of the volume of fluid immobilized in the floc structure to volume of solids in the floc structure as determined from hindred‐settling measurements. These results set an upper limit on the floc size.Under turbulent flow conditions the principle mechanism leading to floc rupture is pressure differences on opposite sides of the floc which cause bulgy deformation and rupture. The breakup of the floc is resisted by the yield stress τy and is promoted by an increase in the energy dissipation per unit mass of fluid ϵ. Because the energy dissipation per unit mass is at a maximum near the pipe wall, the floc size is at a minimum in this same region.By application of the concepts of local isotropy, the floc size is found to be proportional to (τy9/ϵ5)1/2once the turbulent intensity is sufficient to overcome the yield stress. In the wall region the floc diameter is proportional to (du/dr)3 (τy9/ϵ8)1/2.
Numerical and experimental study of damped oscillating manometers: II. Non‐Newtonian fluids
Authors: Biery John C. 
Published: June 2004

AbstractTo test the importance of visco‐elastic properties of non‐Newtonian fluids in an oscillatory system of low frequency the dynamic characteristics of a series of non‐Newtonian fluids were studied in oscillating manometers. The manometer fluid behavior was simulated on a digital computer by numerically integrating the axial component of the equation of motion. In the simulation cone and plate steady state rheological data were represented mathematically with the Sisko rheological model. Good agreement between simulation and experimental data was obtained. This agreement implies that steady state rheological models can be utilized in the description of unsteady state non‐Newtonian systems where the characteristic period of the system is many times greater than the relaxation and retardation times of the fluid. When this characteristic period approaches these times, then rheological models which incorporate viscoelastic terms explicitly probably should be used.
An experimental study of surface cooling by bubbles during nucleate boiling of water
Authors: Rogers Thomas F. , Mesler Russell B. 
Published: June 2004

AbstractBy using a special surface thermocouple Moore and Mesler have measured large temperature fluctuations during nucleate boiling of water on chromel P surface. They found that the temperature dropped 20° to 30°F. in about 2 msec. but required 10 to 20 msec. to recover. They have postulated that the surface was cooled during initial bubble growth by evaporation of a microlayer into the bubble. To test this hypothesis a technique was developed to photograph a bubble growing from an artificial site as the surface temperature was measured.Temperature fluctuations were recorded on an oscilloscope which automatically triggered the bubble photographs by means of a time delay unit and flash tube. Photographs of bubbles were taken at 1 μsec. exposure time and ranged from about 10 μsec. after the start of the temperature drop to about 1 msec. before the start of another cycle. The photographs show that the surface cools during bubble growth and recovers during bubble departure.
Mass transfer in a packed, pulsed column
Authors: Krasuk J. H. , Smith J. M. 
Published: June 2004

AbstractEquations in terms of a pulse Reynolds number and dimensionless pulse velocity are presented for mass transfer coefficients in pulsed flow in a packed bed. Mass transfer from the wall and from the particles is considered. The development, applicable up to a particle Reynolds number of 40, is based upon a previous study of pulsed laminar flow in an empty tube.The experimental measurements consisted of rates of dissolution of β‐naphthol from the wall and from the particles within the bed. From these data time‐average mass transfer coefficients kp were computed. The improvement in kp increased with frequency and decreased with average flow rate, although the increase was always less than in an empty tube at equivalent conditions.Steady flow measurements indicated that the coefficient for mass transfer from the tube wall was influenced by the degree of settling of the bed. This effect could be related to the change in porosity accompanying the settling process. A new empirical correlation is proposed to account for the effect of porosity changes.
The study of gas‐solid equilibrium at high pressures by gas‐chromatography: Part I. Ethane, propane, and n‐butane at essentially infinite dilutions in the methane‐silica gel system
Authors: Gilmer H. B. , Kobayashi Riki 
Published: June 2004

AbstractThe measurement of vapor‐solid distribution coefficients or K values of a solute distributed between a gas phase and an adsorbed phase at essentially infinite dilutions has been investigated. Gas‐solid chromatography is the technique employed in which the solute of interest is eluted through a tube packed with a solid adsorbent by a flowing gas phase which may or may not be appreciably adsorbed. The data taken for the eluted solute samples were then related to the K value and isobaric heat of adsorption for the solutes in the vapor‐solid system.A previous mathematical solution describing the chromatographic process is extended to include the case of an appreciably adsorbed pure component elution gas. This theory allows the calculation of solute K values and heats of adsorption for a solute at essentially infinite dilution in the vapor‐solid system. It is necessary to have adsorption data for the elution gas covering the range of interest. For this reason the necessary elution gas adsorption isotherms were determined gravimetrically for the temperature and pressure range of the study.For comparison purposes a single ethylene adsorption isotherm at 25°C. was obtained along with retention volume data for methane, ethane, and propane at essentially infinite dilution in the ethylene‐silica gel system at 25°C. Agreement of the data of this study and the literature was thought to be sufficiently good to warrant further use of the technique.Methane adsorption isotherms on silica gel were gravimetrically measured at −40°, −20°, 0°, 20°, and 40°C. from 100 to 2,000 lb./sq.in.abs. Retention volume data over the same pressure and temperature ranges were taken for ethane, propane, and n‐butane at essentially infinite dilution in the methane‐silica gel system.
Droplet growth in binary liquid systems
Authors: Ayen Richard J. , Westwater J. W. 
Published: June 2004

AbstractExperimental measurements of the growth of liquid drops suspended in three different, supersaturated, binary liquid mixtures were made with cinephotomicrography. Diameters up to 5μ were reached in from 5 to 500 sec. Results for acetone drops and for isoamyl alcohol drops growing in glycerol solutions agree within 20 and 40% of the theoretical expression of Scriven with mass diffusivities estimated from the Wilke‐Chang correlation. For glycerol drops in acetone, free convection was evident, and the experimental growth rates were lower than predicted by a factor of 5. Scriven's equation seems to be substantiated. Therefore, drop‐growth measurements is a new method for obtaining liquid‐liquid diffusivities, limited however to systems with negligible free convection.
Optimization of multistage cyclic and braching systems by serial procedures
Authors: Aris Rutherford , Nemhauser George L. , Wilde Douglass J. 
Published: June 2004

AbstractThe calculus of variations, dynamic programing, and Pontryagin's maximum principle all are methods for optimzing serial decision processes, the kind associated with multistage operations having no recycle or bypass. Addition of recycle to a serial process makes it cyclic, and branching structures can be built up by connecting serial ones. The concept of cut state makes possible the decomposition of cyclic and branched systems into serial ones solvable by serial procedures. Under favorable circumstances cut states can be directed to their optimum values by efficient optimum seeking methods, which is not possible for ordinary state variables. These method are worthwhile only for loops having at least three stages, and the treatment of converging branches is more complicated than for diverging ones. Visualization of the various system structures is aided by functional diagrams. Definitions and nomenclature are developed for continued research on optimization of macrosystems by serial techniques.
Oscillations of drops falling in a liquid field
Authors: Schroeder R. R. , Kintner R. C. 
Published: June 2004

AbstractFrequencies and amplitudes of oscillations for nineteen pure systems were measured photographically. The period of oscillation was longer than that predicted by Lamb. The discrepancy was not due to wall effects, viscosity, or velocity of fall but to amplitude of oscillation. Modification of previous expressions included an amplitude function which could be experimental or empirical. Oscillations began near the peak velocity, and a vortex trail was necessary for them to take place. Oblate‐prolate oscillations did not cause drop breakup, as all systems ceased to oscillate and wobbled randomly below maximum drop size. Oscillations do not decay with time.
Adsorption of ethyl alcohol on silica gel
Authors: Masamune Shinobu , Smith J. M. 
Published: June 2004

AbstractThis work utilizes the developments of the foregoing paper (10) to analyze adsorption data, in the form of breakthrough curves, for ethyl alcohol on silica gel at 90° to 155°C. It was found that for the smallest particle size, and in the lower part of the temperature range, the overall rate was determined by the surface adsorption process. At other conditions intraparticle diffusion was also a significant resistance in the overall process. The theoretical breakthrough curves agreed well with the experimental ones, so that the surface rate constant and diffusivity could be calculated.Analysis of the diffusivity results showed that surface migration on the pore walls was the predominant contribution rather than gas‐phase diffusion in the pore volume.
Kinetics of the heterogeneous decomposition of iron pentacarbonyl
Authors: Carlton Herbert E. , Oxley Joseph H. 
Published: June 2004

AbstractThe decomposition of iron pentacarbonyl at pressures between one and 400 Torr was studied from 120° to 300°C. Up to about 200°C. the rate was primarily limited by surface kinetics of adsorbed carbonyl. Gas phase diffusional resistances were controlling at higher temperatures. In the kinetically controlled region the deposition rate was correlated by a Langmuir type of equation. Corrections for diffusion resistances in the kinetic region and kinetic resistances in the diffusion region were found to be appreciable.
Hydrates at high pressures: Part III. Methane‐argon‐water, argon‐nitrogen‐water system
Authors: Saito Shozaburo , Kobayashi Riki 
Published: June 2004

AbstractThe experimental procedure for determining the initial hydrate formation conditions along the univariant gas‐water rich liquid‐hydrate locus through the measurement of equilibrium pressures and temperatures alone in a constant volume system has been successfully applied to several binary gas mixtures with water to pressures as high as 15,000 lb./sq. in.The general hydrate theory of van der Waals and Platteeuw, after appropriate modifications, was found valid for the accurate prediction of the initial hydrate formation conditions for selected mixtures of argon‐methane and argon‐nitrogen.The calculated methane‐argon compositions in the hydrate phase are presented as a function of the methane‐argon composition in the gas phase on a water‐free basis but were not verified experimentally.
Stability criteria for miscible displacement of fluids from a porous medium
Authors: Schowalter W. R. 
Published: June 2004

AbstractStability criteria are formulated for displacement of a fluid from an infinite porous medium by a second more dense fluid miscible with the fluid being displaced. Pure displacing fluid is separated from pure displaced fluid by a region of constant thickness in which the two fluids interpenetrate. The steady displacement process takes place at a constant velocity in the direction of gravity. It is shown that appreciable differences in pure‐component densities, viscosity variation within the zone of interpenetration, and the displacement velocity can have a major effect on the stability criteria of such a flow.
Solution of problems involving conventional and complex distillation columns at unsteady state operation
Authors: Waggoner R. C. , Holland C. D. 
Published: June 2004

AbstractThe θ method of convergence has been applied to conventional and complex columns at unsteady state operation. A different holdup for each stage may be specified in terms of molal, mass, or volumetric units. Plate efficiencies were used, and the K values and enthalpies were taken to be polynomials in temperature.
The effect of shape and density on the free settling of particles at high Reynolds numbers
Authors: Christiansen E. B. , Barker Dee H. 
Published: June 2004

AbstractTerminal velocity drag coefficients CD were determined for cylinders, prisms, disks, and spheres in air and water at NRe from 1,000 to 300,000, the regime where particles rotate and/or oscillate. These and other similar data show that CD is a function of particle and fluid densities ρp and ρf, as well as shape and NRe.By considering CD a function of particle moment of inertia and the rotational moment generated by circulation (or alternatively the field force and the lift), one can deduce that \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm C}_{\rm D} = {\rm f}\left({\frac{{\rho {\rm p}}}{{\rho {\rm p}}}\,{\rm or}\,\frac{{\rho {\rm p} - \rho {\rm f}}}{{\rho {\rm f}}},\hbox{a length ratio, N}_{{\rm RE}}} \right) $\end{document}. This relationship correlates the data for ρp = 1.2 to 8.3 and ρf = 0.1 to 1.3 g./cc. to within ± 10%.
Particle flow patterns in a fluidized bed
Authors: Marsheck R. M. , Gomezplata Albert 
Published: June 2004

AbstractA modified thermistor anemometer probe was used to measure solid particle flow patterns in a 9.5‐in. diameter fluidized bed. The probe was calibrated and found to measure the direction and mass velocity of the silica‐alumina cracking catalyst used. Flow patterns were determined at heights of 6.5, 12.5, 18.5, and 24.5 in. above the support plate with superficial air velocity from 0.25 to 1.00 ft./sec. and bed depths of 14 to 30 in.Radial flow patterns were found not to be symmetrical about the axis of the bed but were similar at angles of 60 deg. This indicated that there were six similar particle flow pattern sections around the column axis.The percentage of the cross‐sectional area of the fluidized bed through which the particle flow is upward was found to be approximately 60%. There was no definite dependence of this area on any of the variables studied.The catalyst bulk circulation rate, defined as the average mass velocity of the particles at a given cross section in a fluidized bed without regard to the direction of flow, was determined for each fluidization condition and correlated as a function of the superficial air velocity and the ratio of the distance above the support plate to the height of the fluidized bed.