bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low peclet number heat transfer in the thermal entrance region of parallel‐plate channels with unequal wall temperatures
Authors: Wu Rayshing , Cheng K. C. , Ou Jenn‐Wuu 
Published: March 2009

AbstractThe problem of low‐Peclet‐number thermal entry heat transfer for plane Poiseuille flow in parallel‐plate channels with uniform but unequal wall temperatures is approached by the eigenfunction expansion method utilizing the Gram‐Schmidt orthonormalization procedure. The formulation considers axial heat conduction and allows upstream heat penetration through the thermal entrance. Numerical results are obtained for the case with entrance condition parameter θ0 = 1 and Peclet number Pe = 1, 5, 10 and 50. The effect of Peclet number on temperature distributions in both upstream and downstream regions is studied. At Pe = 50, the concept of thermal boundary layer is applicable and the present series solution does not yield physically reasonable temperature distribution locally near the upper plate at the thermal entrance. The difficulty may be attributed to the nature of thermal boundary conditions at the thermal entrance and the transition from elliptic problem to parabolic problem with the increase of Peclet number.
The thermodynamics of the hydrogenation of oxides of carbon
Authors: Anderson Robert B. , Lee Chung Boon , Machiels Joseph C. 
Published: March 2009

AbstractThe thermodynamics of the hydrogenation of CO and CO2 is summarized. Equilibrium compositions for a number of reactions proceeding simultaneously to yield a number of hydrocarbons and oxygenated organic molecules are reported. If methane is included in these calculations, methane is the predominant product; therefore, for the production of other molecules selective catalysts are required.For producing methane the hydrogenation of CO2 rather than CO may be advantageous, because the reaction is less exothermic. Thermodynamic calculations and results of tests on Raney nickel in a small tubular reactor show that high yields of methane can be obtained in the hydrogenation of both CO and CO2 at temperatures as high as 450°C.
Optimization by catalyst packing in tubular reactors with catalyst decay
Authors: Gruyaert F. , Crowe C. M. 
Published: March 2009

AbstractThe optimal initial distribution of catalyst activity along the axis of a tubular fixed bed reactor is examined for a class of reaction‐deactivation problems. A general set of simultaneous reactions is considered and a quasi‐steady state approximation is used in describing the reaction kinetics. The rate of decay of the catalyst is expressed as a function of temperature, concentration or degree of conversion and catalyst activity. The influence of various initial catalyst activity distributions upon the reactor performance is studied theoretically for several types of decay rate expressions. Numerical results are presented for a single irreversible reaction with a conversion‐dependent decay rate.
Kinetics of hydrogen reduction of cobalt sulfide
Authors: Fahim M. A. , Ford J. D. 
Published: March 2009

AbstractThe hydrogen reduction of cobalt sulfide (Co9S8) at atmospheric pressure in the temperature range 600–800°C has been experimentally investigated. When sulfide pellets were used, the rate constants were overestimated. The true intrinsic kinetics of this reaction were obtained from another set of experiments using sulfide powder, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 600–737°C, the rate constant for the powder reaction could be expressed as:

Above 780°C, cobalt metal whiskers were formed, and this led to swelling and cracking of pellets.
Axial dispersion in a rectangular bubble column
Authors: Stiegel G. J. , Shah Y. T. 
Published: March 2009

AbstractThis paper presents the results of an experimental study on the gas holdup and the liquid phase axial dispersion coefficient in a narrow packed and unpacked rectangular bubble column. In both cases the gas and liquid flow rates were varied and the data were obtained by employing standard tracer technique. The gas holdup and the axial dispersion coefficient for both the packed and unpacked columns were found to be dependent on the gas and liquid flow rates. For given gas and liquid velocities and a given packing size in the case of the packed column, the rectangular column gave significantly higher dispersion coefficients than a cylindrical column of the equivalent cross sectional area. This result agrees very well with the one predicted by the velocity distribution model. The correlations for the Peclet number, the axial dispersion coefficient, and the fluid holdup for both the unpacked and packed bubble columns are presented.
Fluid flow and heat transfer in internally finned helical coils
Authors: Masliyah Jacob H. , Nandakumar K. 
Published: March 2009

AbstractThe equations of motion and energy for Newtonian fully developed fluid flow in an internally finned helical coil were solved numerically for the case of uniform heat flux with peripherally uniform temperature for low Reynolds numbers. Plots for the axial velocity, secondary stream function and fluid temperature are given. For a given fin geometry, it was found that fRe is both a function of Dean number and radius of curvature, whereas the average Nusselt number is a function of Dean number only. For a given fluid at a constant pressure drop, a finned coil gave lower values for the average Nusselt number than a finless tube with the same inside diameter and radius of curvature.
Flow boiling and pool boiling critical heat flux in water and ethylene glycol mixtures
Authors: Frea W. J. , Knapp R. , Taggart T. D. 
Published: March 2009

AbstractFlow boiling and saturated pool trailing were studied in water, and in ethylene glycol and aqueous antifreeze solutions. Boiling took place from an electrically heated cast iron surface at pressures close to atmospheric. In the flow boiling tests, velocities and subcoolings were varied up to 3 m/s and 36°C respectively, and effects of changes in flow passage geometry were examined. In 50 weight percent antifreeze mixtures the pool boiling critical heat flux increased relative to pure ethylene glycol in aqueous solution. Both critical heat flux and heat transfer coefficients decreased as percent water in the mixtures tested was reduced.
Corrosion product transport in water‐cooled. nuclear reactors Part I: Pressurized water operation
Authors: Bvrrill K. A. 
Published: March 2009

AbstractCorrosion of out‐core piping in the primary circuit of nuclear power reactors adds both dissolved and particulate metals and their oxides to the water coolant. The particles deposit on the fuel sheaths and pressure tubes in the reactor core and are irradiated there while they dissolve in the heated water. Transport of now‐radioactive solute around the circuit makes the out‐core surfaces radioactive, which increases radiation exposure to operators and maintainers.A mathematical model has been developed to describe these processes of deposition, irradiation and release of corrosion products on the fuel bundles and pressure tubes of CANDU pressurized water reactors. The model's predictions compare well with data from in‐reactor loop fuel, and data from fuel and pressure tubes from Pickering Generating Station. The model suggests ways to control the growth of out‐core radiation fields and keep them at the current low levels of Pickering. Hot filtration of the reactor water and an increase in water pH are two solutions analyzed with the model.
Effect of turbulence on the precision of velocity and velocity fluctuation data obtained by photochromic visualization
Authors: Humphrey Joseph A. C. 
Published: March 2009

AbstractEven though photochromic flow visualization has been applied to a large range of flow configurations, no analytical study has been made indicating the effects of turbulence fluctuations on the precision of velocity and turbulence data measured by means of the technique. Because of the quick break up and dispersion of photochromic traces by turbulent eddies in the flow it is useful to know a priori the number of observations from which velocity and turbulence data can be determined with a prefixed precision. The paper presents equations and figures from which this and other useful information may be derived.low Reynolds number and by Seeley et al(5) in their
Direct contact condensation from air‐steam mixtures on a single droplet
Authors: Kvlic E. , Rhodes E. 
Published: March 2009

AbstractA new model is derived (and the corresponding numerical algorithm developed) to describe the temperature field of a suddenly exposed droplet experiencing moisture condensation from air‐steam mixture. This model is then compared with the predictions of two simpler models.Experiments done over a wide range of air‐steam concentrations, drop sizes and gas phase velocities show that the combined heat and mass transfer model incorporating partial internal mixing accurately predicts the temperature responses of the droplets.
A contactor for studying mass transfer with reaction in liquid‐liquid systems
Authors: Landau J. , Chin M. 
Published: March 2009

AbstractA contactor has been developed which is especially suitable for experimental investigations of mass transfer with chemical reaction in liquid‐liquid systems. Its function has been tested with the reaction between tetrachlorohydroquinone (dissolved in a mixture of 2‐octanone and carbon tetrachloride) and ceric sulfate (in 0.5M sulfuric acid). In the contactor described in this work the kinetics of this reaction can be investigated in the very slow reaction regime (kinetic regime). It is also possible easily to determine whether a reaction takes place to an appreciable extent in only one or both phases.
Flow dynamics in distillation columns packed with dixon rings as used in isotope separation
Authors: Gilath CH. , Cohen H. , Wolf D. 
Published: March 2009

AbstractPacked distillation columns are common in isotope separation. The pressure drop serves as an indication for the hydrodynamic state of the column. Models were formulated for flow and pressure drop dynamics in packed distillation columns. These models were confirmed on columns packed with Dixon rings and operated with water for separation of oxygen isotopes.Liquid holdup displacement is very important in isotope separation practice. Experiments proved that distillation columns packed with Dixon rings exhibit a behaviour close to plug flow.
Carbonisation de la tourbe pour l'élimination d'ions métalliques en solution aqueuse
Authors: Therien N. , Boucher J. M. , Beerli M. 
Published: March 2009

AbstractThe use of natural peat moss as a cation exchanger is well known. This study considers the ionic exchange characteristics of the powdery material produced by carbonization of the peat.Yields of carbonized peat on a basis of calcium ion exchange capacity have been obtained for different temperatures and times in a tubular fixed bed furnace. Results have indicated a crucial temperature zone for maximum exchange capacity.A critical dependence of the capacity for metal ion removal on the solution to be treated has been demonstrated. Rates of removal have also been characterized. Exchange capacity isotherms were obtained for several metal ions and results for the regeneration of carbonized peat are also reported.
Viscosity of organic liquids at elevated temperatures and the corresponding vapour pressures
Authors: Medani M. S. , Hasan M. A. 
Published: March 2009

AbstractThis work involved the measurement of the viscosities of pure organic liquids at temperatures ranging from 353.15 K to 463.15 K and at the corresponding vapour pressures. A rolling ball viscometer was used where considerable emphasis was given to achieve simplicity and rapidity in obtaining results, without sacrificing the accuracy.Considering the forces affecting the motion of the ball inside the viscometer tube, an equation for the calibration of the viscometer at the same working temperature was derived. The constants of this equation were determined using benzene as the reference liquid, and the dependency of the constants on the temperature was also established. Comparing the derived equation with published ones demonstrated its adequacy in both the streamline and transition flow conditions.The liquids studied were toluene, methanol and n‐hexane. In some cases, the results compared reasonably well with published data while in others, deviations of up to 15% were found.Nine equations were tested with the experimental results for the prediction of the viscosity of these liquids. It was found that the 3‐constant Agrawal and Thodos empirical equation gave the least average deviation.
The solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous dipa solution
Authors: Isaacs E. E. , Otto F. D. , Mather A. E. 
Published: March 2009

AbstractThe solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous solution of di‐isopropanolamine (2.5 kmol m−3 DIPA) has been measured at temperatures of 40 °C and 100°C. Partial pressures of CO2 ranged from 2.0 to 5991 kPa, while partial pressures of H2S ranged from 1.3 to 4126 kPa.
Estimation of thermo‐ and diffusiophoretic particle deposition
Authors: Whitmore P. J. , Meisen A. 
Published: March 2009

AbstractTheories are developed for estimating thermo‐ and diffusiophoretic deposition of particles in liquid as well as gas phase heat and mass transfer equipment, operating under turbulent conditions. Simple expressions are obtained which give satisfactory agreement with experimental data. It is shown that the phoretic effects can lead to appreciable particle deposition, and the practical implications of this, such as heat exchanger fouling, are discussed. The simultaneous occurrence of these and other deposition mechanisms is also considered.
Séparation isotopique d'azote 15 par échange chimique: Influence de la composition des gaz de reflux dans le système NO (gaz.) — N2O3 (liq.)
Authors: Lacoste G. , Bes R. , Routie R. 
Published: March 2009

AbstractA study has been made on the gaz phase composition effect on the isotopic separation of nitrogen 15 for the NO‐N2O3 system. It was shown that the changes in composition of the gas phase could account for the increases in the overall separation.
Fluid mechanics and resource development
Authors: Charles Michael E. 
Published: March 2009

AbstractNovel fluid flow concepts have played important roles in the development of hydrocarbon and other resources. This has occurred frequently in such areas as mining and production, pipeline transportation and resource processing. Examples of interesting flow concepts drawn from experience with a wide variety of projects are discussed with the thought in mind that they may prove useful in the search for improved and new methods for the extraction of hydrocarbons from oil sands.
A theory for predicting the maximum spoutable height in a spouted bed
Authors: Littman Howard , Morgan Morris H. , Vuković D. V. , Zdanski F. K. , Grbavčić Ž.B. 
Published: March 2009

AbstractA theory is presented for predicting the maximum spoutable height, in a spouted bed where fluidization of the annular solids limits the penetration of the fluid jet entering the bed.The quantity (Hmds/(D – d) is found to be a function of ds/Dc only for spherical particles and
\[ \frac{{H_m d_S }} {{(D_c^2 ‐ d_S^2 )}} = 0.345\left( {\frac{{d_S }} {{D_c }}} \right)^{ ‐ 0.384} \]
where the spout diameter is calculated using McNab's correlation(7). Insertion of McNab's correlation into Equation (1) shows that Hm is proportional to D and the effect of dp on Hm varies from d to d as the particle Reynolds number increases assuming 1 ≥ (ds/D).Using experimental value of ds, the calculated values of Hm differ from the experimental ones by 8.5% on average.When small particles are spouted with air, the penetration of the jet is limited by the formation of a slug in he spout and the theoretical value provides an upper limit for Hm.
The oxidation of ortho‐xylene on vanadium pentoxide catalysts II. The influence of catalyst support material on product distribution
Authors: Wainwright M. S. , Hoffman T. W. 
Published: March 2009

AbstractThe oxidation of o‐xylene has been investigated on a number of commercial vanadia catalysts in an isothermal packed bed reactor. The data show that phthalic anhydride selectivities of up to 85 mol percent can be obtained on titania supported catalysts whereas maximum values of around 30 mol percent are achieved on silica supported catalysts.An attempt at modelling the kinetics of the reactions using the Redox mechanism is reported. The results indicate that this model is not adequate to fully describe all reactions. Some of the difficulties are indicated and suggestions are made for modifications to the models along with directions for future work.
An exploratory study of the behaviour of crude oil spills under ice
Authors: Greene G. D. , Leinonen P. J. , Mackay D. 
Published: March 2009

AbstractAn experimental spill of 0.38 m3 of warm (55°C) crude oil under the ice cover of a fresh water pond with an underwater viewing port is described. Temperatures, dissolved hydrocarbon concentrations and oil slick behaviour and areas were determined. Some oil recovery and disposal methods were tested. An attempt has been made to quantify the rates of heat and mass transfer from the oil using reported values for transfer coefficients. The results indicate that the oil slick adopted a thickness of about 2 cm under the ice, that heat transfer from the oil was relatively fast and complete, that dissolution mass transfer is slow resulting in oil concentrations in the water of only 18 to 287 μg/l in the vicinity of the spill. Some recommendations are made for further studies to elucidate the nature and rates of the relevant physical processes and thus assist in assessing the environmental impact of under‐ice oil spills.
A generalized one‐parameter redlich‐kwong equation for vapor‐liquid equilibrium calculations
Authors: Kato Masahiro , Chung W. K. , Lu Benjamin C.‐Y. 
Published: March 2009

AbstractThe two modified parameters previously proposed for the Redlich‐Kwong (RK) equation of state are simplified and reduced to a one‐parameter model, and extended to vapor‐liquid equilibrium (VLE) calculations involving supercritical components. However, the original RK parameters are still treated as temperature‐ and substance‐dependent.In this investigation, this parameter is generalized in terms of Tr and Ω. The values obtained from the generalized correlation are suitable for calculating VLE data at T ≤ Tc for all components, and at temperatures where some of the components are in the supercritical region.The validity of the generalized correlation is supported by its ability to represent saturated properties of the pure components and to predict VLE data for five binary systems at 58 isothermal conditions, and one ternary system at two isothermal conditions.
A simple model to calculate the solubility of liquid water in compressed air
Authors: De Santis R. , Marrelli L. 
Published: March 2009

AbstractA perturbed hard‐sphere equation of state is used to calculate the solubility of liquid water in compressed air at pressures up to 40 MPa.The proposed model does not require the knowledge of ternary data and is generally applicable to the calculation of the solubility of polar or associating liquids in non polar gases.
Bulk and interfacial physical properties of aqueous solutions of sodium lauryl sulphate and lauryl alcohol with air and benzene system: Part I: Aqueous solutions of sodium lauryl sulphate
Authors: Vijayan S. , Woods Donald R. , Vaya Helene 
Published: March 2009

AbstractExperimental measurements were made of the pH, density, bulk viscosity and electrical conductivity of aqueous solutions of sodium lauryl sulphate for a wide range of concentrations at 25°C. Also, the time‐dependent interfacial tension data of this system with mutually saturated benzene phases are reported. Comparison of these data with literature values shows fair agreement in the majority of the cases and further reveals the lack of data in the earlier investigations below the critical micelle concentration of sodium lauryl sulphate in water.A detailed compilation of the data, reported in the literature since 1937, of the pH, density, bulk viscosity, electrical conductivity, surface tension, interfacial tension with benzene, surface excess concentration, surface shear viscosity, diffusivity and critical micelle concentration of the sodium lauryl sulphate system is given. The importance of this anionic surfactant system together with the various factors which influence the physical properties is examined.
Motion of liquid drops in rheologically complex fluids
Authors: Acharya A. , Mashelkar R. A. , Ulbrecht J. 
Published: March 2009

AbstractThe influence of viscoelasticity and of the shear‐dependent viscosity of ambient liquids on the motion of liquid drops was examined experimentally. In the low Reynolds number region (Re < 1) the influence of elasticity is insignificant and the influence of the variable viscosity is well accounted for by the existing correlations. At higher Reynolds number (Re > 1) the viscoelasticity brings about a substantial increase of drag. An interpretation of this phenomenon is attempted in view of the changes of the wake behind the drop and an empirical correlation in terms of the Weissenberg number is suggested. Additionally it was found that the “wave theory” as presented by Marrucci et al(8) can be satisfactorily used for drops moving at Re > 10 irrespective of rheological complexities.
Conditions minimales de mise en fluidisation par un liquide
Authors: Riba J. P. , Routie R. , Couderc J. P. 
Published: March 2009

AbstractLa vitesse minimum de mise en fluidisation d'une charge de particules sphériques par un liquide est relié aux variables caractéristiques du système par la relation:

Cette corrélation, contrairement à celles rencontrées dans la biblographie, ne fait pas intervenir le degré de vide de la couche au seuil de fluidisation.
Effective interfacial area in packed beds for absorption with chemical reaction
Authors: Patwardhan V. S. 
Published: March 2009

AbstractThe extended crossflow model is proposed and developed for describing gas absorption with chemical reaction in a packed bed operated in the trickle flow regime. The model involves the division of the total interfacial area into the interfacial area of the static hold‐up and that of the dynamic hold‐up. The concept of the effectiveness of the interfacial area of the static hold‐up is presented. A procedure is developed for calculating the effectiveness, and consequently, the effective interfacial area for various different absorption processes with chemical reaction, both liquid phase controlled and gas phase controlled. The predictions based on the present model agree well with reported experimental data. The present model is shown to be simpler and more accurate than previous models.
Corrosion product transport in water‐cooled nuclear reactors: Part II: Boiling water with direct cycle operation
Authors: Burrill K. A. 
Published: March 2009

AbstractCorrosion product transport in a water‐cooled nuclear reactor causes gamma‐radiation fields to grow around the heat transport circuit. An hypothesis is given which identifies some of the mechanisms causing radiation field growth in a CANDU direct‐cycle, boiling water reactor. Overall, predictions from a mathematical model of the hypothesis agree well with data. Comparisons are made for deposit weights of iron on fuel sheaths and for radionuclide specific activities in deposits on the fuel sheaths of the CANDU prototype direct‐cycle, boiling water reactor at Gentilly, Quebec. As well, radionuclide specific activities measured in particles in the water, and in deposits in the steam drums are compared with the model. Filtration of corrosion products from the reactor feedwater is suggested as one way to control radiation field growth.