bluuebunny/crossref_metadata_2025_split huggingface dataset:
Turbulence suppression in solutions and pure liquids
Authors: Oliver D. R. , MacSporran W. 
Published: March 2009

AbstractExperiments dealing with the onset of turbulent flow in very small capillary tubes are described. The liquids are water, n‐heptane, toluene and four aqueous solutions containing small quantities of a polymeric additive.The transition from laminar to turbulent flow is delayed in a manner dependent on tube diameter. There is an essential similarity between the behavior of all the liquids. Possible reasons for the observed behavior are discussed and it is suggested that the explanation lies in the presence of varying degrees of elasticity in the liquids used.Using normal stress data from a jet thrust apparatus, the transition values of various dimensionless groups are evaluated.The group which gives the most consistent behavior is the inertio‐elastic number equivalent to a Reynolds number in which viscous shear stress is replaced by elastic normal stress.
Calculation of ternary equilibrium vapor compositions from total vapor pressure‐liquid composition data
Authors: Chang Shinn‐Der , Lu Benjamin C.‐Y. 
Published: March 2009

AbstractA simple and direct method for evaluating ternary vapor‐liquid equilibrium compositions from measurements of the total vapor pressure exerted by the liquid phase along lines of constant liquid mole fraction ratio is presented. Application has been successfully made to the ternary system nitrogen‐argon‐oxygen at 180°r. The proposed method modifies that for binary systems and can be conveniently applied to ternary systems at low to medium pressures.
Laminar and turbulent flow in annuli of unit eccentricity
Authors: Bourne D. E. , Figueiredo O. , Charles M. E. 
Published: March 2009

AbstractExperimental results are presented for the flow of water in eccentric annuli having unit eccentricity in the laminar, transition and turbulent flow regimes at Reynolds numbers between 200 and 20,000. In both the laminar and turbulent regimes the interesting result is obtained that, for a given Reynolds number, the friction factor is a minimum at a diameter ratio of about 0.750. The experimental results are compared with previous theoretical analyses in the laminar region, and with previous experimental data at Reynolds numbers exceeding 20,000 in the turbulent region. A further interesting result relates to the transition region where, at intermediate diameter ratios, the transition from laminar to turbulent flow becomes more diffuse. This appears to be a consequence of the gradual change from laminar to turbulent flow brought about by the variation in local Reynolds number from zero to a maximum value within the eccentric annulus. It is believed that sufficent experimental data are now available for the pressure gradient to be predicted for flow in eccentric annuli of unit eccentricity over a relatively wide range of Reynolds number.
Heat transfer from teflon‐treated surfaces under flow conditions
Authors: Al‐Shahristani H. , Andrews D. G. 
Published: March 2009

AbstractThe effect of Teflon spot treatment of the heating surface on nucleate boiling under flow conditions has been investigated. This effect is found to be complicated, varying strongly with temperature difference and degree of sub‐cooling. In general, for high degrees of subcooling, there is some improvement in the heat transfer coefficient for Teflon‐treated surfaces at low temperature differences, and an opposite effect at high temperature differences. Teflon spot treatment does not produce any appreciable effect at very low degrees of subcooling. An attempt has been made to explain this complex effect of Teflon treatment, taking into account maximum and minimum bubble diameters and insulating effect of Teflon spots.
Filtration of non‐Newtonian fluids
Authors: Kozicki W. , Tiu C. , Rao A. R. K. 
Published: March 2009

AbstractEquations of motion characterizing the flow of incompressible, time‐independent non‐Newtonian fluids, exhibiting the anomalous surface effect, through compressible porous media are developed. Approximations are made to arrive at workable filtration equations for slurries of non‐Newtonian (power‐law) fluids. The constant‐pressure and constant‐rate filtration relationships developed are verified experimentally using slurries of calcium carbonate in water and dilute CMC solutions. The anomalous surface effect is found to exist in the filtration of the non‐Newtonian fluids. The specific cake resistance in the case of the non‐Newtonian sludge and the ratio of the effective slip velocity to the pore velocity are found to be functions of both the CMC concentration and the pressure drop across the filter bed.
The mathematical representation of a light hydrocarbon refining network
Authors: Petryschuk W. F. , Johnson A. I. 
Published: March 2009

AbstractThe block‐relaxation method, system‐tH equations and a direct sequential calculation have been combined to solve the non‐linear algebraic equations describing the steady‐state behavior of a multi‐recycle network of five distillation towers and two reactors. Approximately 2,000 such equations are solved in 30 minutes of IBM 7040 computation time.The existence of optimum tolerances on individual column calculations and on individual recycle calculations is demonstrated. The application of the block‐relaxation method to a network of distillation columns is numerically shown to simultaneously converge the network equations and the individual column equations to the final solution.
Time sub‐optimal control of the gas absorber
Authors: Chant V. G. , Luus R. 
Published: March 2009

AbstractProper choice of the weighting matrix Q in the Liapunov function V = x' Q x followed by the minimization of the forward difference δV gives sub‐optimal control which can come close to the time optimal control. Several methods of determining such a weighting matrix are presented and these methods are compared and evaluated with respect to a six‐plate gas absorber. The choice of the sampling time for the discrete‐time model is very important, and its effects on the best weighting matrix and the resulting control policy are illustrated. The results of this investigation yield an efficient iteration algorithm whereby Q is successively improved until the sub‐optimal control policy approaches the time optimal control.
A test of the withdrawal theory for ellis fluids
Authors: Hildebrand Richard E. , Tallmadge John A. 
Published: March 2009

AbstractThe Ellis withdrawal theory is shown to be a eubstantial improvement for predicting film thickness as compared to the previous theory for pseudo‐plastic fluids. The two‐term Ellis power‐law theory ie shown to be a good approximation to the Ellis theory. The relative deviations between data and Ellis theory become larger at lower speeds.
An investigation into the stability of enclosed laminar diffusion flames
Authors: Deckker B. E. L. , Srinivas R. A. 
Published: March 2009

AbstractExperiments on enclosed laminar diffusion flames have revealed the existence of a critical relative velocity of air and fuel which is associated with the threshold of low frequency flame vibration. Starting from the hypothesis that these vibrations are triggered by a selectively amplified disturbance arising in the free shear layers near the base of the flame, the authors have obtained evidence of the nature of the disturbance. Further systematic experiments have enabled them to account for the observed behavior of low frequency vibrating diffusion flames in the light of their hypothesis and in relation to the acoustical properties of their combustion system.
Diffusion‐controlled adsorption processes
Authors: Anderson R. B. , Hamielec A. E. , Stifel G. R. 
Published: March 2009

AbstractNumerical solutions of differential equations for diffusion‐controlled adsorption processes in spherical particles are presented for slow diffusion of gaseous molecules followed by rapid adsorption according to the Langmuir isotherm. As the parameter in the denominator of the Langmuir equation is increased the rate increases and the generalized rate curves shift progressively from that for the linear isotherm, the Langmuir parameter = 0, to the curve of the parabolic law. Adsorption and desorption cycles are considered and parameters are provided for relating any of these processes to the generalized curves. A simple linear equation was shown to approximate the rate curves with moderate accuracy.
Qualitative and quantitative observations on the tubular reactor
Authors: Amundson Neal R. , Luss Dan 
Published: March 2009

AbstractThe tubular reactor in the steady state is considered for a single chemical reaction. It is shown that almost all of the qualitative features of the temperature and concentration profiles may be deduced from the equations themselves without solving them. Extensive numerical calculations are also presented both for the finite and semi‐infinite reactor. Comparisons are made with the lumped constant system. It is shown that the solution for the semi‐infinite reactor is always unique and serves as a bounding solution for all finite reactors with the same parameters.
Hydrogen reduction of chromium chlorides: A kinetic investigation
Authors: Rigg Tyson , Innes David B. K. 
Published: March 2009

AbstractThe reduction of single pellets of chromic and chromous chlorides by hydrogen has been studied kinetically. The reaction 2 CrCL3 + H2 →2 HCl + 2 CrCl2 was investigated over the temperature range 475−615°C. The rate controlling factor in the range of 475−493°C. is vaporization of chromic chloride; the activation energy was found to be 67.8 K.cal./mole. Between S10 and 615°C, the reaction rate is evidently controlled by heat and internal mass transfer processes. In this case the apparent activation energy is 16.6 K.cal./mole.Reduction of chromous chloride, CrCl2 + H2 → 2 HCl + Cr, was investigated over the temperature range 675−800°C. This reaction is also controlled by heat and mass transfer and involves vaporization of the chromous chloride. The apparent activation energy is 25.5 K.cal./mole.
Extractive metallurgy at international nickel — A half century of progress
Authors: Renzoni L. S. 
Published: March 2009

AbstractThe R. S. Jane Memorial Lecture Award was established to commemorate the memory of the late Dr. Robert Stephen Jane who made an outstanding contribution to the chemical profession and the chemical industry in Canada. It is presented to a resident of Canada for exceptional achievement in the field of chemical engineering or industrial chemistry. The Lecture is presented at the annual C.I.C. Canadian Chemical Engineering Conference. Mr. Renzoni, recipient for 1968, presented this paper at the 1968 Tripartite Chemical Engineering Conference, September 22–25, 1968, in Montreal, Quebec.
Sedimentation of two prolate spheroids in close proximity
Authors: Hnatow M. , Pfeffer R. , Happel J. 
Published: March 2009

AbstractExperiments concerned with the rate of fall of two prolate spheroids (needle‐like objects) in close proximity to each other are described in this paper. Quantitative agreement with S. Wakiya's theoretical predictions is obtained for the case in which two prolate spheroids are settling, one above the other, in the direction perpendicular to their axis of symmetry and for the case in which two prolate spheroids are settling end to end in the same horizontal plane in the direction perpendicular to their axis of symmetry.These experiments and this theoretical treatment apply only in the creeping motion region. At higher velocities, inertial effects would become significant.
Interfacial effects for transient heat conduction in the non‐continuum regime
Authors: Picot J. J. C. 
Published: March 2009

AbstractExperimental results are given which show that for non‐continuum conditions for heat conduction between a solid surface and a gas, there is a surface zone (of probably four or five mean free paths in thickness) where the “effective” thermal conductivity gradually changes from a value governed by gas — solid wall interactions to the normal continuum value in the bulk phase. In the temperature‐jump range, the effect of this surface zone in steady‐state situations can be adequately expressed by a temperature‐jump distance, but this approach is inadequate for transient state situations. In the transient state, a theory is required which allows for the gradually changing effective thermal conductivity in the surface zone.
Simultaneous heat and mass transfer through laminar boundary layers in combined forced and free convection
Authors: Barton H. J. , Trass Olev 
Published: March 2009

AbstractHeat and mass transfer rates from a vertical plate are reported for combined free and forced convection. Heat transfer coefficients were obtained from temperature gradients at the wall and mass transfer rates from thickness decrease measurements of naphthalene coatings.The free convection data cover a Grashof number range from 100 to 2 × 108 and the combined flow parameters Gr/Re2 and Gr'/Re2 vary from 0.2 to 100 and 2 × 10−8 to 3.25, respectively. Predictions from boundary layer solutions are in good agreement with the data.Absorption of ultraviolet light by naphthalene vapor was used to measure free convection concentration profiles. Results prove the versatility of this method.
Simultaneous heat and mass transfer from a single sphere to a turbulent air stream
Authors: Boulos Maher I. , Pei David C. T. 
Published: March 2009

AbstractA study of the simultaneous heat and mass transfer from a single sphere to a turbulent air stream has been made. The aim of the investigation is to evaluate the effect of mass transfer on the rate of heat transfer. Results are compared with pure heat transfer data under similar conditions as well as those obtained by the evaporation of liquids from porous spheres.
Mass transfer from single gas bubble — a comparative study on experimental methods
Authors: Garbarini Gail R. , Tien Chi 
Published: March 2009

AbstractA comparative study on the experimental techniques which have been used for the study of mass transfer from single gas bubble was made. The instantaneous mass transfer rates from a single carbon dioxide bubble rising through quiescent liquid medium (water) were measured using two different methods. For the first method, two movie cameras were placed on a moving platform along perpendicular directions and were used to record the position and size change of the bubble. The second method measured the mass transfer rates by recording the pressure changes in the free space at top of the bubble column, which was caused by the change of bubble size. The instantaneous mass transfer coefficients determined by either method exhibited wide scattering which is typical of work of this kind. Discussions are given on the relative merits of these two methods.
On liquid‐liquid mass transfer inside drops in a turbulent flow field
Authors: Boyadzhiev L. , Elenkov D. , Kyuchukov G. 
Published: March 2009

AbstractMass transfer in liquid‐liquid dispersions in a turbulent flow field has been investigated for the particular case where the overall process rate is governed by the diffusional resistance in the dispersed phase. Experiments with the system water‐iodine‐carbon tetrachloride have shown that the transfer mechanism in this case is similar to that for single drops at high Reynolds numbers. The results obtained show that the so‐called correlation factor R depends strongly on the turbulence of the system. This relationship can be expressed as R ˜ R2, which is valid for the mass transfer rate both in turbulent liquid‐liquid dispersions and for some cases of solute diffusion in single oscillating drops.
Kinetics of cupric oxide catalysed oxidation of propylene in a stirred reactor
Authors: Lakshmanan R. , Rouleau D. 
Published: March 2009

AbstractThe catalytic air oxidation of propylene to acrolein over a supported copper oxide catalyst was investigated in a continuous stirred vessel reactor between 375° and 450°C at atmospheric pressure. The effect of temperature, ratio of oxygen to propylene in feed and total feed rate (or contact time) on the conversion of propylene and the yield of acrolein were determined. It was found that with an increase in temperature, ratio of oxygen to propylene and contact time, the yield drops considerably though conversion increases.A study of the mixing characteristics of the stirred vessel reactor was carried out by following the conversion at various stirrer speeds.The kinetic data obtained were tested to determine the most probable model by the Hougen‐Watson method. The model that satisfactorily correlated the data describes the rate‐controlling step as the surface reaction occurring between adsorbed propylene, a vacant site and oxygen in the gas phase. The following Hougen‐Watson type rate equation has been proposed

The constants in the rate equation have been expressed as a function of temperature.
Isothermal adsorption in fixed beds
Authors: Lee Robert G. , Weber Thomas W. 
Published: March 2009

AbstractPrediction of single component adsorption in a packed bed operated isothermally is accomplished through the use of a mathematical model. The model accounts for the diffusional resistance between the bulk gas and the surface of the adsorbent particles, and for the diffusional resistance within the particles. The adsorption reaction within the pores is assumed to be very rapid compared to these two rate controlling mechanisms. The model can be used for isotherms of any shape and for gaseous feeds of any concentration. The partial differential equations of the model were solved numerically. Breakthrough curves are presented for four different isotherms and for two feed concentrations. The extension of the model to handle surface diffusion is treated. The model is compared with that of Rosen ≥11, 20 and the differences are discussed.
Equilibria in binary liquid — adsorbent systems
Authors: Shelstad K. A. , Wong S. W. 
Published: March 2009

AbstractAdsorption equilibrium data at 25°C. for toluene‐n‐heptane mixtures in contact with three types of adsorbent carbon, silica gel, and alumina, and for o‐xylene — m‐xylene mixtures on one carbon were correlated in terms of a capacity factor Z and a separator factor a. The capacity Z was found to be less than the pore volume and the mono‐molecular area calculated from Z was found to be smaller than the butane surface area of the adsorbent. Values obtained for a ranged from 4.74 to 10.2 depending upon the system.
Designing experiments for precise estimation of all or some of the constants in a mechanistic model
Authors: Hunter William G. , Hill William J. , Henson Thomas L. 
Published: March 2009

AbstractAn important experimental problem in chemical engineering is to collect data in order to estimate constants such as rate constants and activation energies which are needed, for example, in equipment and plant design. For a given amount of experimental effort, the engineer wants these constants to be estimated as precisely as possible. In this paper, we discuss statistical design procedures that might be used to accomplish this goal. Available procedures are reviewed for estimating precisely all the constants in a mechanistically based mathematical model. In addition, a new procedure is illustrated for precisely estimating only some of the constants which may be of more interest than the others.
The effect of changes in initial reactant composition on solid‐gas equilibria resulting from constant‐volume, adiabatic processes
Authors: Van Zeggeren F. , Storey S. H. 
Published: March 2009

AbstractA method is given for the computation of the chemical equilibria attained by adiabatic chemical reactions in similar systems, all with the same volume and mass, as a result of changes in the initial reactant compositions. Changes in equilibrium composition and temperature are directly related to changes in the initial elemental abundances, in the form of a set of simultaneous equations. Since it is not necessary to perform complete calculations for each solution required, the solution of these equations constitutes a saving in computation. The method can be applied to solid‐gas systems. The systems must be ideal or they have to obey an empirical equation of state, wherein covolume is a function of volume only.
On the use of the imperfect tracer pulse method for determination of hold‐up and axial mixing
Authors: Øsstergaard K. , Michelsen M. L. 
Published: March 2009

AbstractThe imperfect pulse method is a powerful technique for experimental analysis of chemical engineering flow systems. The authors have employed this method in studies of holdup and mixing in gas‐liquid fluidized beds. In the present paper are discussed two problems connected with reduction of the experimental data obtained in such studies.Tailing is a phenomenon that may seriously affect the accuracy of mixing coefficients determined by the imperfect pulse method. Accurate methods of data reduction, based upon analysis of moments, have been developed, and their applicability is demonstrated by analysis of experimental data.Interphase transfer of tracer material is of particular importance in investigations of gas phase mixing in a gas‐liquid system where absorption of tracer gas into the liquid phase normally takes place. A semiempirical method is described for correction of the experimental data in such cases.
Axial mixing of liquid in a turbulent‐bed contactor
Authors: Chen B. H. , Douglas W. J. M. 
Published: March 2009

AbstractThe axial dispersion of liquid in a 12‐in. turbulent‐bed contactor has been investigated for three packing sizes: ½‐in., 1‐in. and 1½‐in. The gas and liquid flow rates were varied from 500 to 2700 lb./(hr.)(sq. ft.) and from 1500 to 11,000 lb./(hr.)(sq. ft.) respectively. The transient response technique using KCl solution as the tracer was employed for this purpose.The experimentally determined residence‐time distribution curves were interpreted by means of a one‐dimensional dispersion model. The axial dispersion coefficient, DL, was found to increase with increasing gas flow rate, liquid flow rate, or packing size. In terms of Peclet number (NPe = ū dp/DL), the present data showed that NPe was dependent on Reynolds number (N, = dp ū ρ/μ), Gallileo number (NGa = dp3 ρ3 g/μ2), and reduced gas mass velocity (Δ = (G‐Gmf)/Gmf), but the ratio of the Peclet number for a turbulent contactor to the Peclet number for a fixed‐bed contactor, NPe/NPeo, depended only on Δ, and the diameter ratio dp/dt. A correlation of NPe/NPeθo with Δ and dp/dt is presented.
Mixing models with varying stage size
Authors: Fan L. T. , Chen Michael S. K. , Ahn Y. K. , Wen C. Y. 
Published: March 2009

AbstractTwo progression models which can be employed to represent flow systems with varying degree and mode of mixing along the direction of flow such as a shallow fluidized bed, radial flow reactors, and short tubular reactors, etc. are proposed. Residence time distributions are derived from the standpoint of stochastic processes. The use of progression models is illustrated with a second order, isothermal reaction.
Prediction of thermodynamic properties of polar mixtures by a group solution model
Authors: Ratcliff G. A. , Chao K. C. 
Published: March 2009

AbstractA modified group solution model for liquid mixtures is presented. The model differs from previous models in that the Bronsted‐Koefoed congruence principle is used to describe the effect of molecular size. The model has been tested for mixtures involving paraffin hydrocarbons, alcohols and water at low pressures. Such systems involve binary mixtures of the groups methylene and hydroxyl, and are reasonably represented by the model.Data presented enable the approximate equilibrium properties of such solutions at low pressures to be predicted at 40°C and 90°C. Interpolation and reasonable extrapolation from these temperatures should be satisfactory.