bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axial dispersion and heat transfer in liquid‐liquid spray towers
Authors: Mixon F. O. , Whitaker D. R. , Orcutt J. C. 
Published: June 2004

AbstractA radioptracer technique was utilized to measure axial dispersion in both phases in spray towers operated at and near flooding. A new method that exhibits certain advantages over methods employed in the past is presented for reducing such data. It is demonstrated that axial dispersion in flooded and near‐flooded spray towers is sufficiently severe to control completely their performance as heat exchangers.
An experimental study of nonisothermal effectiveness factors in a porous catalyst
Authors: Miller F. W. , Deans H. A. 
Published: June 2004

AbstractCirculating hydrogen‐oxygen mixtures were reacted at atmospheric pressure in a single long porous catalyst cylinder which contained a thermocouple‐micromanometer probe. Rate and temperature rise data were obtained at 20°, 30°, 50°, and 60°C. in the concentration range 0 to 5% oxygen in hydrogen.The data were used in connection with the transport equations to obtain effectiveness factors, rate constant, activation energy, and reaction order for oxygen concentration.The necessity of considering thermal effects is exhibited clearly by this system. The maximum temperature rise observed inside the catalyst (33°C.) is associated with a 60% increase in utilization factor over the isothermal value.
Critical flow of liquid‐vapor mixtures
Authors: Cruver James E. , Moulton R. W. 
Published: June 2004

AbstractA unified theory of one‐dimensional, adiabatic, separated, two‐phase flow is presented. To describe the flow adequately, four mixture specific volumes are defined. They are based on area, momentum, kinetic energy, and velocity averages. Increasing relative velocity between the phases initially lowers all mixture specific volumes except the velocity average. The momentum average specific volume minimizes when the slip ratio equals (Vg/Vf)1/2, while the kinetic energy average specific volume reaches its minimum value at a slip ratio of (Vg/Vf)1/3. Area average specific value does not minimize with slip ratio.Because a higher slip ratio would decrease the entropy of a closed system, (Vg/Vf)1/3is the maximum slip ratio attainable in two‐phase critical flow. Based on the maximum slip ratio and isentropic flow, a new critical flow model was developed and compared with the steam‐water critical flow data of four recent investigations. While the predicted flow rates followed well the pressure behavior of the experimental data, they were too low at high qualities and too high at low qualities. The average percentage difference between experimental and predicted critical flow rates was −8.5% (three hundred and seventy‐six data points).Differences in the approach to critical flow between a gas and a vapor‐liquid stream appear to be caused by the latter's increased frictional and gravitational pressure drops and relative velocity effects.
Gas absorption by drops traveling on a vertical wire
Authors: Rajan Shanti Mohan , Goren Simon L. 
Published: June 2004

AbstractIn the measurement of the absorption of carbon dioxide gas by a series of oil drops moving down a vertical wire the variables studied are drop frequency, oil viscosity, wire size, and column length. A model is proposed which assumes that the gas is absorbed by almost stagnant liquid film between and covering the drops, that the film is subsequently mixed with a drop as it moves past, and that the dissolved gas is carried from the column in circulating loops of liquid within the drops. The model leads to an equation which correlates the data and gives a good approximation to the slope of the line.
Isobaric integral heats of vaporization for methane‐ethylene system
Authors: Tully Philip C. , Edmister Wayne C. 
Published: June 2004

AbstractAn isobaric calorimeter has been built for measuring the integral heat of vaporization at high pressures and low temperatures simultaneously with vapor‐liquid equilibria data. The methane‐ethylene system was studied at 20 and 40 atm., with data obtained on three mixtures and the two pure components. The experimental results are compared with three different calculation methods.
Adduction in the decane‐urea‐ethanol system: Part I. Equilibrium studies
Authors: Tamarelli A. W. , Manning F. S. 
Published: June 2004

AbstractPhase equilibria in the decane–urea–ethanol system were investigated between 15° and 40°C. Solubility limits for urea–decane adduct in ternary liquid solutions and for urea in ethanol were measured over the entire feasible range of compositions, thus defining the phase diagrams. Activity coefficients estimated for the saturated liquid solutions reflected strong positive deviations from ideality. The magnitudes were consistent with the results of independent vaporliquid equilibrium studies.
Stability of loop reactors
Authors: Luss Dan , Amundson Neal R. 
Published: June 2004

AbstractA method of determining all the possible steady states of a tubular recycle reactor with plug flow is presented. The information needed to determine the steady states can be used to ascertain the asymptotic and global stability of the reactor without performing transient computations. The effects of changes in the recycle ratio and start‐up conditions are examined. Several numerical examples are included to demonstrate the use of the method for various types of recycle reactors.
The identification of nonlinear reaction systems with two‐level inputs
Authors: Harris G. H. , Lapidus Leon 
Published: June 2004

AbstractThe general problem of characterizing a nonlinear, physical process from its input‐output records is examined. A method of identifying the class of nonlinear, time‐invariant processes with switched two‐level inputs and finite memories is successfully applied to several nonlinear systems. The identification model consists of a finite, orthogonal series expansion for the output as a function of the past of the input. Of particular interest is the characterization and synthesis of a nonlinear, continuous stirred‐tank reactor. This system, as well as others that are investigated, is simulated on a digital computer and identified after an initial observation period. No specific knowledge of the unknown process is presumed; however, only moderately fast input switching is permitted. After synthesizing the identification model, the process and model outputs are compared.
Application of molecular corresponding states theory to highly nonideal liquid mixtures
Authors: Wheeler Joe D. , Smith Buford D. 
Published: June 2004

AbstractThere are four points of flexibility in present molecular formulations of the corresponding states idea. At these points the procedure followed or the numerical values can be tailored to achieve better agreement between predicted and experimental properties without violation of physical principles. These flexibilities are the exponent values used in the pair‐potential function, the averaging procedure used to obtain an effective mixture pair‐potential function, the combination rule for unlike‐pair parameters, and the selection of a reference substance. The first two flexibilities are used in this paper to show that the conformal‐parameter equations can correlate excess free energy and activity coefficient data of highly nonideal liquid mixtures. A pair‐type‐probability function is introduced in the averaging procedure used to obtain a mixture pair‐potential function. Any macroscopic or molecular property may be used in this weighting function to improve mixture‐property prediction.
An application of noninteracting control to a continuous flow stirred‐tank reactor
Authors: Foster Robert D. , Stevens William F. 
Published: June 2004

AbstractA general method, given in a companion paper, by which an interacting linear multivariable system may be decoupled into independent subsystems, is applied to a continuous flow stirred‐tank reactor. The form of the compensating controllers required for the physical system is obtained. It is then verified numerically that noninteraction is achieved, as postulated, by simulation of the linear model with compensating control on the analog computer.
Flow work exchanger
Authors: Cheng Chen‐Yen , Cheng Sing‐Wang , Fan Liang‐Tseng 
Published: June 2004

AbstractIn a high‐pressure process, feed streams are continually pressurized and product streams are continually depressurized. A flow work exchanger offers an efficient and economical scheme for simultaneously pressurizing a fluid stream and depressurizing a substantially equivalent volume of another fluid stream. Its applicability is however limited to fluids under condensed state. A flow work exchanger uses a displacement vessel to form a closed loop with a processing system. The displacement vessel is alternately filled by a low‐pressure feed and a high‐pressure product, both pressurized and depressurized, respectively, by substantially nonflow processes. The pressurized feed is pushed into the processing system by the high‐pressure product stream and the depressurized product stream is pushed out of the displacement vessel by the low‐pressure feed stream. The application of a flow work exchanger is illustrated by means of several high‐pressure processes and the direct and indirect advantages obtainable are described.
Analysis of data in reverse osmosis with porous cellulose acetate membranes used
Authors: Kimura Shoji , Sourirajan S. 
Published: June 2004

AbstractReverse osmosis experimental data for some inorganic salts with the porous cellulose acetate membrane used were analyzed to obtain their diffusivity in the membrane. A parameter including the diffusivity was found constant for each film in the concentration range investigated for a particular solute at a particular pressure. This parameter was also independent of feed flow rate. The effect of operating pressure on the parameter was found to depend on the film shrinkage. Mass transfer coefficient between the membrane and the feed solution was also obtained by the analysis, and this value was independently checked by the diffusion current method. Coincidence of these coefficients shows that the ordinary mass transfer coefficient can be used in reverse osmosis with the appropriate driving force. These facts facilitate the prediction of solute separation and membrane throughput rate in reverse osmosis.
Forced and natural convective mass transfer in multicomponent gaseous mixtures
Authors: Carlton Herbert E. , Oxley Joseph H. 
Published: June 2004

AbstractThe use of the Chilton‐Colburn analogy to obtain an effective film thickness over which the Stefan‐Maxwell equations can be integrated was confirmed for binary mixtures and found applicable for ternary, quaternary, and presumably higher order mixtures under conditions of nonequimolal counterdiffusion in a differential convective flow system. A method of averaging binary diffusivities was developed for use in computing the Schmidt number in these multicomponent systems. It was also found necessary to modify the usual Sherwood number, if there was a large molecular weight change across the diffusion barrier when the Chilton‐Colburn analogy was employed.
An experimental study of nonequimolal diffusion in ternary gas mixtures
Authors: Getzinger R. W. , Wilke C. R. 
Published: June 2004

AbstractThis work is an experimental test of the Stefan‐Maxwell equations as applied to cocurrent, steady state gaseous diffusion of two species through a stagnant third component. The Stefan capillary tube method was used to measure the diffusion rates. The use of constant evaporating binary liquid mixtures made possible boundary conditions that were invariant with time. Total molar losses were compared with the predictions of the theory to demonstrate the validity of the equations under conditions of a significant convective flux.
Gas‐liquid mass transfer with a tangentially moving interface: Part I. Theory
Authors: Byers Charles H. , King C. Judson 
Published: June 2004

AbstractA theoretical investigation has been made of the effect of a moving interface upon gas‐liquid mass transfer, where the control of the mass transfer is entirely within the gas phase and where the control is distributed between the two phases. An analytical model is proposed for laminar interphase mass transfer in infinite media. Computer solutions have been obtained for gas‐liquid mass transfer in confined phases. A cocurrent moving interface increases mass transfer confficients over what they would be for the same flow rate without interfacial motion.
A correlation for pressure drop in two‐phase cocurrent flow in packed beds
Authors: Sweeney D. E. 
Published: June 2004

AbstractA correlations has been developed from considerations of single‐phase flow behavior to predict pressure drop across packed beds for two‐phase cocurrent flow. The correlation does no require one of the assumptions made in previous correlations, and thus it was not necessary to relate empirically any dimensionless groups through the use of experimental two‐phase flow data. The only empiricism involved in the use of this correlation is that required in correlating single‐phase pressure drops through packed beds, an art well developed in the literature. The correlation as developed here is at least as accurate as previous correlations in this area and may be more reliable when used for two‐phase systems not previously studied experimentally.
The phase and volumetric relations in the helium—n‐butane system: Part II. Second virial coefficients for helium—n‐butane mixtures
Authors: Jones Allan E. , Kay Webster B. 
Published: June 2004

AbstractThe second virial coefficients of pure n‐butane and of two mixtures of helium and n‐butane were determined in the range 100° to 225°C. from isothermal compressibility measurements. Values of B11 (pure n‐butane) agree closely with those of McGlashan and Potter (11) at low temperatures and of Hirschfelder et al. (7) at higher temperatures. Values of the mixed second virial coefficient B12 were computed from the mixture data. B12 shows little variation with temperature over this interval. The interpretation of the data as the behavior of a mixture composed of hard sphere (helium) in a real gas (n‐butane) is discussed.
Sorption and diffusion of gaseous hydrocarbons in synthetic mordenite
Authors: Satterfield Charles N. , Frabetti Alton J. 
Published: June 2004

AbstractDiffusion coefficients for the C1 to C4 paraffin hydrocarbon gases in single crystals of the synthetic zeolite (molecular sieve) sodium mordenite were determined from transient sorption rate and desorption rate measurements over the temperature range 25° to 140°C. and pressure range 0 to 20 cm. Hg, and found to be of the order of 10−9 to 10−10 sq. cm./sec. Diffusion coefficients for desorption were from three to sixty times smaller than those for sorption. Activation energies for methane and ethane were 1.7 and 1.9 kcal./mole, respectively.Equilibrium sorption capacity and diffusion coefficients are markedly affected by the conditions of synthesis and by mechanical treatments such as grinding. For propane at 29°C. and at 2.0 cm. Hg pressure, the sorption capacity in 2.5 μ crystals was only 50% of that in 21 by 21 by 33 μ crystals and the diffusion coefficient was only 1/50 of that in the larger crystals. Light mechanical grinding of the larger crystals lowered the sorption capacity 30% and the diffusion coefficient by a factor of 35.
The growth of ice crystals in a stirred tank
Authors: Harriott Peter 
Published: June 2004

AbstractIce crystals were grown in water or sodium chloride solutions by direct contact with evaporating butane. In water subcooled 0.01° to 0.05°C., the particles grew about one‐quarter to one‐half as fast as fast as predicted from heat transfer correlations. The growth rates in 2% salt solution were about sevenfold lower than those obtained in water at the same subcooling, because the concentration difference for salt diffusion lowered the interface temperature. Calculations indicate the diffusion effect to be much greater for disk‐shaped particles than for spheres.
Bubble frequencies and departure volumes at subatmospheric pressures
Authors: Cole Robert 
Published: June 2004

AbstractBubble frequencies and departure volumes in nucleate pool boiling have been obtained for a variety of liquids at pressures ranging from 50 to 760 mm. Hg. The bubble dynamic data conclusively show the volumetric vapor flow rate to be a strong function of the Jakob number in qualitative agreement with the heat transfer measurements of Nickelson and Preckshot. The data also indicate the volumetric vapor flow rate per cross section to be independent of the Jakob number, in agreement with existing equations.
On thermal conductivity of liquids
Authors: Viswanath D. S. 
Published: June 2004

AbstractThe Bridgman equation for thermal conductivity of liquids is examined and a relation between sonic velocity and latent heat of vaporization is given. A correlation based on the hole theory of liquids is presented. This correlation predicts thermal conductivity in the temperature range of −20° to +80°C. for sixteen liquids, and at 20°C. for fifty liquids with an average absolute deviation of 9.5 and 5%, respectively. The correlation is also applied to liquid metals.
Experimental study of the viscous sublayer in turbulent pipe flow
Authors: Popovich A. T. , Hummel R. L. 
Published: June 2004

AbstractA flash photolysis method for nondisturbing turbulent flow measurements has been applied to study conditions in the viscous sublayer in a square smooth pipe. Experimental results are obtained that are extremely difficult to obtain by any other known technique.The results show that, adjacent to the wall, there is a layer of very small thickness y+ = 1.6 ± 0.4 in which a linear velocity gradient occurs virtually at all times, but the slope of the gradient changes with time. Beyond y+ = 34.6 essentially turbulent flow exists. In the transition region in between, very disturbed flow conditions prevail. However, the technique used clearly indicates the instantaneous velocity distribution in the flow field bewteen the wall and the fully turbulent region.Statistical distributions of the instantaneous wall shear stress (evaluated from the slope of the velocity gradient), the laminar sublayer thickness, and the velocity at the edge of the laminar sublayer are obtained. It follows that the partial turbulence mechanism whereby the flow at a point is turbulent only a fraction of the time is, at least to an extent, responsible for the reduction of eddy diffusivity by kinematic viscosity close to the wall.Experimental velocity profile obtained in the present investigation is compared with the proposed and experimental velocity profiles of other authors.
Analysis of liquid phase adsorption fractionation in fixed beds
Authors: Morton E. L. , Murrill P. W. 
Published: June 2004

AbstractLiquid phase adsorption has been one of the latest unit operations to receive theoretical treatment because of the relative complexity of the mechanisms involved. The purpose of this investigation is to present an improved method for solving problems, especially where intraparticle diffusion is a rate controlling mechanism. Appropriate boundary conditions for liquid phase adsorption and a general nonlinear equilibrium relation are included in deriving a system of partial differential equations describing the process.The mathematical model consists of a bulk phase material balance, an intraparticle diffusion equation, and a rate for interphase transfer; these equations must be solved simultaneously with the boundary conditions and equilibrium function. A numerical procedure is developed and discussed for use on a high‐speed computer.The results are sets of computed curves for four liquid systems, each requiring a separate computer solution because of changes in feed concentration or equilibrium relationship. It is shown that for three of the four systems tested in this research, experimental data correlate with computed results better than in earlier work. Although the solution of this model has been carried out for particular examples, it should be applicable in the case of other liquid phase systems following the assumed mechanisms.
Vapor‐liquid equilibria at high pressures: Calculation of critical temperatures, volumes, and pressures of nonpolar mixtures
Authors: Chueh P. L. , Prausnitz J. M. 
Published: June 2004

AbstractAn analysis of critical data for a larger number of binary mixtures of normal fluids shows that the critical temperature and the critical volume can each be expressed as quadratic functions of the surface fraction. Each of these functions requires one adjustable parameter characteristic of the binary pair; for any family of chemical components, these parameters, upon suitable reduction, follow definite trends. It was shown that the surface fraction gives much better correlation than any other size‐weighted variable. For the critical pressure, however, no quadratic function was adequate. To calculate critical pressures, the correlations for critical temperature and critical volume were used in conjunction with a slightly altered version of the Redlich‐Kwong equation.Generalizations to systems containing more than two components follow without additional assumptions. The methods presented in this paper provide good estimates for critical constants of multicomponent mixtures. These are particularly useful for analyzing and correlating vapor‐liquid equilibria in the critical region.
Heat transfer in liquid‐liquid spray towers
Authors: Greskovich E. J. , Barton Paul , Hersh R. E. 
Published: June 2004

AbstractAn experimental investigation of heat transfer rates in which were used three spray towers varying from 4 to 6 in. in diameter and 7 to 10 ft. in height, and distributor elements with hole sizes varying from 1/8 to 1/64 in. in diameter was carried out. The immiscible liquid system consisted of water and kerosene (normal boiling point range 395° to 490°F.). Volumetric heat transfer coefficients ranged from 100 to 3,600 B.t.u./(hr.)(cu. ft.)(°F.) and the overall film heat transfer coefficients ranged from 4 to 23 B.t.u./(hr.)(sq. ft.)(°F.). Height equivalent to a theoretical stage varied from 1 to 8 ft. Scale‐up correlations relating these rate data to operating variables were developed.
Drop formation at low velocities in liquid‐liquid systems: Part I. Prediction of drop volume
Authors: Scheele George F. , Meister Bernard J. 
Published: June 2004

AbstractA correlation is presented for predicting the drop volume for injection at low velocities of one Newtonian liquid into a second stationary immiscible Newtonian liquid in the absence of surface active agents. The analysis, which is based on a two‐stage process of drop formation, predicts drop volumes within an average error of 11% for fifteen liquid‐liquid systems covering a wider range of variables than any previous study. Although the equation was tested primarily with mutually saturated liquids, if correctly predicted drop size for two systems where mass transfer was occurring.
The numerical solution of large systems of linear differential equations
Authors: Davison E. J. 
Published: June 2004

AbstractIn chemical engineering and process control, the numerical solution of large systems of linear, time‐invariant, differential equations must often be considered. Standard numerical techniques such as the Runge‐Kutta method usually require excessive computational time. Since often the time solution of only a few variables is desired in such large systems, a method has been developed to take advantage of this and allows the solution of large systems of differential equations to be obtained in an extremely fast and efficient manner. The basis of the method is to solve for the poles and zeros of the system and then to find the time solution in terms of these poles and zeros.