bluuebunny/crossref_metadata_2025_split huggingface dataset:
A variable‐density model of the pipeline flow of suspensions
Authors: Shook C. A. , Daniel S. M. 
Published: March 2009

AbstractThe turbulent flow of suspensions of fine solid particles in liquids is analyzed by assuming that the suspensions behave essentially as variable‐density single phase fluids. Friction factors are found to depend upon the distribution of solid particles within the conduit as well as the Reynolds number of the flow. Comparison of the model with experimental measurements indicates that as long as turbulent suspension of solid particles occurs, the model is a useful alternative to the empirical Durand equation for pipeline design.
Effect of a dilute “drag‐reducing” polymer solution on a float‐type flowmeter
Authors: Fvlford G. D. , Arunachalam Vr. 
Published: March 2009

AbstractIt has been found experimentally that very dilute polymer solutions of the type known to reduce turbulent pipe friction drag affect the calibration of “rotameter” type flow meters. This effect appears to decrease with increasing age of the solution.
Freezing of hydraulic systems
Authors: DesRuisseaux N. , Zerkle R. D. 
Published: March 2009

AbstractA theoretical technique is developed for predicting the conditions under which a hydraulic system freezes shut. The investigation considers laminar liquid flow through a tube between two reservoirs. Freezing is assumed to occur within a portion of the tube having a uniform wall temperature lower than the liquid freezing temperature. Analytical results indicate the minimum allowable pressure drop which must be maintained across the system to prevent it from freezing shut. The theoretical predictions are then compared with experimental results.
Cocurrent gas‐liquid flow in horizontal tubes with internal spiral ribs
Authors: Zarnett G. D. , Charles M. E. 
Published: March 2009

AbstractThe flow of air‐liquid mixtures has been investigated in 3/4‐inch internal diameter Lucite tubes fitted with continuous spiral ribs having pitch‐to‐diameter ratios of 1.57 and 2.79. Descriptions and photographs of the flow patterns are presented for reasonably wide ranges of gas and liquid flow rates. The main effect of the spiral rib was to move the gas phase away from the tube walls. The flow patterns were classified as bubble, plug, slug‐stratified, slug‐semiannular and slug‐annular. The pressure gradient data were successfully correlated with the Lockhart‐Martinelli parameters, although the resulting curves showed small displacements from the Lockhart‐Martinelli correlation for smooth tubes.
Dissolution mass transfer in a turbine agitated baffled vessel
Authors: Nienow A. W. 
Published: March 2009

AbstractMass transfer coefficients were measured for the dissolution of crystalline electrolytes suspended in a baffled vessel by means of disc turbines. A 3‐fold range of density differences, a 5‐fold range of diffusivities and a 50‐fold range of particle size were covered and the effect of impeller speed, size and clearance from the base was studied.The increase in coefficent with speed is both a function of the clearance and solid density and size and is difficult to quantify. However, in the most economic configuration of small clearance and large impeller, this is not of great importance since the coefficient increases but slowly with speed and the minimum suspended coefficient can be calculated. This is done by means of a slip velocity theory which has been extended to include larger particles, which allows for the effect of concentration dependent physical properties and which is based on the impeller speed at which particle suspension occurs.
A method for estimating inter rivulet mixing
Authors: Porter K. E. , Stephens G. K. 
Published: March 2009

AbstractA method is presented for estimating inter rivulet mixing in liquid running in film flow down a packed bed. The method is based on comparing an experimentally measured tracer distribution with the theoretical distribution at several levels below the plane of tracer injection. The change in the number of traced rivulets is then estimated statistically. Experimental results for water running over Raschig rings show that inter rivulet mixing may be estimated from two experimentally determined parameters, a collision frequency factor and a mean size of rivulet.
Interprétation cinétique des mesures d'ignition dans le cas des systèmes réactionnels gaz‐solide
Authors: L'Homme G. A. 
Published: March 2009

AbstractCette étude propose une interprétation quantitative du phénomène d'ignition en vue de déterminer leg paramètres cinétiques des réactions chimiques exothermiques du type: gaz + solide → gaz.Deux méthodes cinétiqueg sont préconisées dans le cas où le processus chimique se produit dans le régime cinétique, et leurs modalités d'application pratique sont discutées. La première méthode est à coefficient de transfert thermique gaz‐solide variable d'une mesure d'ignition à l'autre, tandis que la seconde est à coefficient de transfert thermique constant: elles permettent de déterminer la cinétique réactionnelle à partir de la mesure des conditions expérimentales régnant à l'ignition.Ces méthodes sont ensuite appliquées avec succès à un système réactionnel de géométrie, d'hydrodynamique et de mécanisme cinétique compliqués: l'oxydation catalysée d'un noir de carbone, mesurée dans une installation thermo‐gravimétrique.
The analysis of residence time distribution measurements using laguerre functions
Authors: Anderssen A. S. , White E. T. 
Published: March 2009

AbstractThe residence time distribution of a flow system can be determined from the response of the system to an arbitrary input, by a technique invoving Laguerre functions. This technique is convenient for digital computation, and is comparable in accuracy with other methods. The effects of the nature of the flow system, the arbitrary input, and the presence of noise are considered.
The optimization of the catalytic oxidation of sulphur dioxide in a multi‐bed adiabatic reactor
Authors: Chartrand G. , Crowe C. M. 
Published: March 2009

AbstractA multi‐bed adiabatic reactor for the catalytic oxidation of sulphur dioxide was optimized using maximum conversion as the criterion and with plant data from Canadian Industries Limited, Hamilton, Ontario. Different combinations of the following parameters were varied: number of beds, inlet temperature to each bed, bed depth and air dilution before each bed. The optimization techniques used and compared for efficiency were: dynamic programming, gradient search, Hooke and Jeeves' pattern search and the discrete maximum principle.The optimum conversions were found to be quite insensitive to considerable variation in feed temperature, air dilution and catalyst distribution. An improvement in the plant conversion of 0.25% was predicted.
Optimum estimation of process parameters using pseudo‐random binary signals with application to mixing inside a packed tower
Authors: Woodburn E. T. , King R. P. , Everson R. C. 
Published: March 2009

AbstractA technique is described for the design of a test signal such that the parameters, defined by the axial mixing model for a packed tower, can be estimated with the greatest accuracy from experimental records.Methods for calculating the effect of additive noise, usually associated with small amplitude signals, on computed correlation‐, spectral‐and amplitude ratio estimates are discussed.Designed experiments were performed on a 10‐in. I.D. packed tower by the injection of a radioactive tracer into the gas phase. Peclet numbers for both dry and irrigated beds are reported.
The activity of commercial water gas shift catalysts
Authors: Ruthven D. M. 
Published: March 2009

AbstractPublished kinetic data for commercial water gas shift catalysts are interpreted in terms of pore diffusional effects. The Arrhenius plots of apparent activity show the curvature typical of the transition from reaction to pore diffusion control and the apparent activities of different catalyst pellets vary quite widely. Effective diffusivity data are used to calculate intrinsic rate constants from the apparent activity data and it is found that the intrinsic activities of the catalysts considered are all similar. Furthermore the intrinsic activities, calculated in this way, give linear Arrhenius plots and activation energies which are in good agreement with values obtained experimentally using small catalyst particles (22–27 K. Cals). The effect of pressure on apparent catalyst activity is also discussed and it is shown that this effect may be accounted for satisfactorily by pore diffusional effects and it is not necessary to assume a change in the intrinsic rate equation at least at pressures below 20 atms.
The effect of baffle spacing on the dynamics of shell and tube heat exchangers
Authors: Chang D. R. C. , Tinker E. B. 
Published: March 2009

AbstractThis note reports on some aspects of the effect of shell side baffle geometry on the dynamic behaviour of flow forced shell and tube heat exchangers. Frequency response data for four heat exchangers with different baffle geometry were obtained. A second order critically damped transfer function gave an adequate description of the dynamic behaviour. The apparent natural frequency is a function of the shell‐side and tube‐side flow rates and fluid properties, as conveniently expressed by the overall heat transfer coefficient; and of the size and shape of the baffle compartments, as expressed by the ratio of shell diameter to baffle spacing.
Exact solution for diffusion to flow down an incline
Authors: Rotem Zeev , Neilson John E. 
Published: March 2009

AbstractThe concentration of solute in a film flowing down an inclined plane has been obtained by solving the complete diffusion equation, including the diffusion effect in the direction of flow. The formulation leads to the necessity of solving non‐orthogonal characteristic value problem, treatment of which is, however, quite straightforward.Though the motivation for the study was the diffusion of oxygen to plasma or blood films, solutions are presented for the complete range of fluid properties, due to the great significance of this mode of flow for wider application in chemical engineering.
Minimum stable bubble volumes and bubble collapse rates in gas fluidized beds
Authors: Godard K. , Richardson J. F. 
Published: March 2009

AbstractMeasurements of the collapse rates of small bubbles injected into particulate gas fluidized beds show that the net transfer rate of gas from the bubbles to the continuous phase decreases as the background velocity is increased. The results indicate that the minimum stable bubble volume in a bed fluidized at a velocity equal to twice the minimum fluidizing velocity is 0.08 cc. Evidence of increase in the continuous phase voidage in the path followed by a bubble has been observed; this would explain the formation of stable bubble tracks.
Reactions of carbon vapor with a mixture of argon‐propane in a high intensity arc
Authors: Cholette A. , Covrtois P. A. , Parent J. R. 
Published: March 2009

AbstractA high intensity arc reactor wag used to react carbon with a mixture of argon and propane at three different volumetric concentrations. The reaction output, when quenched, gives essentially C2H2, and hydrogen. The acetylene output depends mostly on the reaction temperature and on the carbon‐hydrogen ratio.While higher concentrations of C2H2 might be obtained by operating the arc with a mixture of argon and propane rather than with pure propane, the efficiency of carbon utilization would be lowered when propane is diluted, the effect being more pronounced at higher concentrations of the diluent. The temperature of the carbon‐propane system is influenced to a small extent only by the presence of a diluent.
Scale‐up of continuous flow stirred tank reactors
Authors: Keairns D. L. 
Published: March 2009

AbstractA model of a continuous flow stirred tank reactor based on laboratory experiments successfully describes the behavior of a pilot plant reactor. This model simulates the pilot plant performance over the full range of operating conditions: at high impeller speeds where performance approaches that of a perfectly mixed reactor and at low impeller speeds where performance significantly differs from perfect mixing. The micro‐mixed feed model divides the continuous flow stirred tank reactor into a small micro‐mixed impeller zone and a large macro‐mixer.
Continuous‐flow electrodialysis of acetate, butyrate, and chloride: A correlating equation
Authors: Schrodt J. Thomas , Yonikas Patrick J. , Grieves Robert B. 
Published: March 2009

AbstractAn experimental investigation is presented of the electrodialysis of acetate or butyrate with chloride, in a continuous‐flow unit with a membrane area of 50 cm.2 separating a test cell pair. The effects on the transport of the individual anions are established of several independent variables, including membrane type, organic specie, mole fraction of organic in the feed, and current density. Polarization is evident at a current density of 8 ma./cm.2A semi‐empirical equation is developed and, utilizing the experimental data, the equation yields the cell constant and the ratio of the diffusivity of each anion to the film thickness. The equation, relating the purification factor (ratio of feed and effluent concentrations) and the key independent variables, may be utilized to correlate and extend a rather limited number of data points for other chemical systems in other continuous‐flow units.For both membranes, both organic species, and over a wide range of feed mole fractions and current densities, the mole fraction of an anion transported across the membrane can be related to the feed mole fraction by a simple power relation, indicating a convenient way of expressing membrane selectivity.
Combined liquid‐ and vapor‐phase hydrocracking of heavy oil
Authors: Quinsey D. H. , Merrill W. H. , Herrmann W. A. O. , Pleet M. P. 
Published: March 2009

AbstractA combined liquid and vapor‐phase pilot plant designed to hydrocrack heavy residues, pitches and bitumen containing high concentrations of nitrogen, sulphur and inorganic solid contaminants is described. Results are presented of preliminary experiments using the vacuum bottoms from Weyburn crude oil as a feed.
Gradient technique and lagrange multiplier – A technique for optimizing complex processes
Authors: Lee E. Stanley 
Published: March 2009

AbstractThe gradient technique combined with Lagrange multiplier is used to find the optimum of a complex heterogeneous process with two recycle streams. Both the reaction stages and the separation stages for the separation of a six component mixture are considered. In spite of the complexity of the process, only two minutes computation (IBM 7094) is needed to obtain the solution. Techniques for handling inequality constraints on the control and state variables are also discussed.
Design of differential countercurrent extractors with backmixing using stagewise models
Authors: Mecklenburgh J. C. , Hartland S. 
Published: March 2009

AbstractMethods are presented which enable the behavior of a differential contactor with backmixing to be estimated from that of a stagewise model with equivalent backmixing. The latter requires fewer stages than the models previously proposed. The inherent instability of the equations renders the boundary iteration method of solving the stagewise equations unreliable. However, this instability may be avoided by simultaneous solution of the equations and furthermore it is possible to reduce the amount of computer storage required if an unsteady state method is used.
The growth and dissolution of potassium sulphate crystals in a fluidized bed crystallizer
Authors: Mullin J. W. , Gaska C. 
Published: March 2009

AbstractThe nucleation, growth and dissolution characteristics of potassium sulphate have been studied in a laboratory scale fluidized bed crystallizer under carefully controlled conditions of temperature, supersaturation and solution velocity. Aqueous solutions of potassium sulphate can withstand high degrees of supercooling (∼ 13°C) even when agitated, but this is reduced to about 5°C when the crystalline phase is present. Nevertheless, this is still a high level of supercooling for an aqueous salt solution. The importance of measuring nucleation data for crystallizer design purposes under the appropriate conditions is clearly demonstrated.The ‘order’ of the nucleation process, m, defined by Rn = KnΔcm is about 9. The growth process, defined by Rg = KgΔcn is second‐order (n = 2) with an activation energy of 4.3 kcal/mole, and the dissolution process, Rd = KdΔcp, in first‐order (p = 1) with an activation energy of 3.4 kcal/mole.The growth step is therefore considered to be diffusion controlled, and this is confirmed by the observation that the growth rate of potassium sulphate in a fluidized bed is dependent on the size of the crystals.
Group contributions in vapor‐liquid equilibrium
Authors: Rodger Alan J. , Hsu Cheng C. , Furter William F. 
Published: March 2009

AbstractAn empirical method has been developed for the prediction of vapor‐liquid equilibrium data, both composition and temperature, for a series of binaries of chain hydrocarbons with carbon tetrachloride. The maximum and absolute average deviations in vapor composition are 0.035 and 0.006 mole fraction, respectively, and in temperature are 1.5 and 0.4°C, respectively. Because of assumptions inherent in the theory, the prediction (as opposed to correlation) tends to apply only with chain compounds and not with compounds containing rings. Systems containing cyclic and aromatic hydrocarbon compounds, however, have been correlated by this method with some degree of success.
The quasi‐steady‐state approximation in continuous stirred tank reactors
Authors: Ray W. H. 
Published: March 2009

AbstractThe Quasi‐steady‐state‐approximation (QSSA) applied lo continuous stirred tank reactors (CSTR) is examined. The induction period is found to be somewhat longer and the error in the QSSA larger than for batch reactors. This error is usually insignificant except when CSTR conversions are low. An alternative approximation is proposed for this case. The errors in the QSSA are also illustrated for the well known cases of Enzyme and Free‐Radical polymerization kinetics.
Kinetic energy and momentum factors for rough pipes
Authors: Booth Robin G. , Epstein Norman 
Published: March 2009

AbstractKinetic energy and momentum factors are derived, evaluated and presented for fully developed turbulent flow in both uniformly sand‐roughened and commercial pipes as a function of Reynolds number and relative roughness. For the uniform sand roughness, the universal velocity profile and friction factor equations of Nedderman and Shearer were used, while for the commercial roughness the corresponding equations of Colebrook and White were employed.
Temperature distributions in a helium plasma
Authors: Meubus P. , Parent J. R. 
Published: March 2009

AbstractTemperature distributions are determined in a helium plasma, the power used being 27 kW and the gas flow rate 7.2 g/minute. Pressure conditions for the plasma under study are respectively 760 and 300 mm Hg.The spectroscopic method used for obtaining temperatures is that of Larenz or the method of maximum emission, applied to the 3,889 Å neutral helium line. A maximum temperature, on the plasma axis, of approximately 24,000° K is obtained.
Velocity distributions in a gaseous plasma: I. Derivation of flow types within a helium plasma
Authors: Meubus P. , Parent J. R. 
Published: March 2009

AbstractVelocity distributions in a plasma jet are generally determined by means of direct methods which are liable to alter the medium, especially at very high temperatures. A gas flow model is proposed, which is worked out from the luminous profile of a helium plasma jet, such as viewed through a dense orange glass filter. The knowledge of the luminous profile equation, temperature distribution, gas flow rate and energy balance completely determine the velocity distribution in the plasma. Boundary conditions lead, in certain cases, to the concept of an axial turbulent core. The helium plasma was operated at 27 kW, with a gas flow rate of 7.2 g/minute. The jet was issuing into an atmosphere kept at 300 mm Hg in order to favor conditions leading to laminar flow.
Experimental study of natural convection heat transfer from a vertical plate in a non‐newtonian fluid
Authors: Sharma K. K. , Adelman Maurice 
Published: March 2009

AbstractAn experimental investigation of natural convection heat transfer to non‐Newtonian fluids from isothermal vertical plates was carried out. Three aqueous solutions of Carbopol 934 (1.25%, 1.5% and 1.75%) were selected as pseudoplastic fluids providing a flow behavior index range from 0.2 to 0.67. All the experimental data lay in the laminar flow range (NGrNPr < 109). A successful correlation for predicting natural convective heat transfer coefficients for non‐Newtonian fluids from flow behavior index 0.2 to 1.0 inclusive was developed.
Experimental study of natural convection heat transfer in a non‐newtonian fluid: Part II. Horizontal plate
Authors: Sharma K. K. , Adelman Maurice 
Published: March 2009

AbstractExperimental data on natural convection heat transfer to non‐Newtonian fluids from isothermal horizontal flat plates facing both up and down are reported. Emperical expressions for predicting the heat transfer coefficient for fluids as the flow behavior index is varied from 0.19 to 1.0 were developed. These are essentially similar to the vertical plate case and correlate the data with reasonable accuracy.
Mass transfer from a single rising bubble
Authors: Johnson A. I. , Besik F. , Hamielec A. E. 
Published: March 2009

AbstractThe absorption rates of carbon dioxide, ethylene, and butene from single rising bubble of equivalent diameter 0.4–2.0 cm in water have been measured using an apparatus in which the bubble volume change with time of rise can be measured. The apparatus uses techniques previously reported but also is suitable for studies of mass transfer without and with chemical reaction at higher pressures (up to 4 atmospheres). The results have been compared with theoretical equations for rate of gas solution at the frontal surface of the bubble based upon potential flow theory and Higbie theory.The data are assessed together with those of others to show that they can be correlated well byThis equation is valid for bubbles of equivalent diameter 0.6 < d < 4.0 cm and within the range500 < NRe < 20,000
The dynamics of extraction processes: Part II. Comparison of dynamic testing methods and their application to an extraction process
Authors: Pollock G. G. , Johnson A. I. 
Published: March 2009

AbstractA comparison of the theoretical and experimental difficulties and advantages of sinusoidal, pulse, and step testing procedures, as applied to a continuous stagewise extraction process, is made.An experimental extraction apparatus suitable for a variety of dynamic studies is described. For this apparatus step testing has been found to give results as reliable as those from pulse methods.The paper develops the theoretical background and describes experimental implementation of double pulse testing.The extraction column when used with the system water‐acetic acid‐methyl isobutyl ketone was found to behave linearly over the range of variables studied. The stages of the column were found to be “well‐mixed”, and it was concluded that the column could be best represented by a lumped parameter model.
Studies on yield in gas‐liquid contacting reactors
Authors: Ohki Yoshihiro , Inoue Hakuai 
Published: March 2009

AbstractAnalytical solutions giving the yield of a first order consecutive reaction in a gas‐liquid contacting reactor are derived for cocurrent, countercurrent plug flow and perfectly mixed flow systems. The general solutions derived from the consideration of both reaction and transfer processes by a new mathematical method clarify the effect of mass transfer rate on the yield. Special solutions with the condition of infinite mass transfer rates can be used to choose the best flow system and to calculate the operating conditions for the greatest reactor yield.