bluuebunny/crossref_metadata_2025_split huggingface dataset:
Turbulent flow behaviour of dilute polymer solutions in an annulus
Authors: Tiu Carlos , Chee Ngee‐Onn 
Published: March 2009

AbstractAn experimental study has been carried out to investigate the turbulent flow behaviour of dilute polymer solutions in an annulus. The polymers used are two grades of Separan, AP30 and MG500, both are known to exhibit drag reduction characteristics in turbulent pipe flow. Similar drag reduction phenomena have been observed in annulus flow. At a given Reynolds number, the friction factor decreases with increase in polymer concentration and appears to reach a minimum (or maximum drag reduction) at certain optimum concentration. An estimate of the critical wall shear stress, which marks the onset of drag reduction, is consistent with pipe flow results, suggesting that the critical value is independent of flow geometry and size. A lower drag reduction, achieved in an annulus in comparison with circular pipes, is attributed mainly to a diameter effect.
Simultaneous heat and mass transfer in turbulent gas streams in wetted‐wall columns
Authors: Hikita H. , Ishimi K. , Asano K. , Ohba Y. 
Published: March 2009

AbstractThe effect of the gas and liquid flow rates on the gas‐phase mass and heat transfer rates in turbulent gas streams in wetted‐wall columns with cocurrent and countercurrent gas‐liquid flow was studied. The experiments were carried out on the adiabatic vaporization of water into a turbulent air stream under both conditions of rippling and no rippling on the surface of the falling liquid film. The experimental results showed that the effect of the gas and liquid flow rates on the mass and heat transfer rates are in good agreement with the theoretical predictions and that the effect of the rippling on the mass and heat transfer rates can be neglected.
The oxidative dehydrogenation of ethylbenzene to styrene
Authors: Degannes Percival N. , Ruthven Douglas M. 
Published: March 2009

AbstractThe results of a kinetic study of the oxidative dehydrogenation of ethylbenzene to styrene over an organic catalyst (pyrolyzed polymerized acrylonitrile) are reported. The reaction is found to be second order in ethylbenzene and zero order in oxygen with an activation energy of 76.5 kJ/mol. The rate equation is: \documentclass{article}\pagestyle{empty}\begin{document}$ - r(mol/\min .g\,catalyst) = 3.2 \times 10^9 \exp [ - 76,500/RT] \cdot C_{EtB}^2 \cdot C_{O_2 }^0 $\end{document} where R = 8.31 J/niol.K and concentration (CEtB) is expressed as mol/L. The catalyst is more active than conventional metal oxide catalysts and appears to be quite stable under reaction conditions. The results suggest that, using the PPAN catalyst, it may be possible to reduce the operating temperature of the oxidative dehydrogenation of ethylbenzene to about 250‐300°C, thereby avoiding some of the problems of the present high temperature process.
Gas holdup and aerated power consumption in mechanically stirred tanks
Authors: Yung C. N. , Wong C. W. , Chang C. L. 
Published: March 2009

AbstractGas holdup and mechanical power consumption were measured in aerated aqueous nonelectrolyte and electrolyte systems. The experiments were performed in 0.4 m diameter cylindrical flat‐bottomed and hemispherical‐bottomed tanks. Standard six‐blade turbine (D/T = 0.225, 0.325, 0.45) and four‐blade paddle (D/T = 0.225, 0.325) were used over a wide range of gas sparging rate and power dissipation. A semiempirical correlation for holdup with dimensionless groups, i.e. impeller Weber number, aeration number and ratio of impeller diameter to tank diameter has been developed; however, this correlation did not fit the electrolyte solution data. The power consumption data of both the impeller types and tank bottom types were found to fit satisfactorily the Michel‐Miller correlation with 20% accuracy.
Rheological properties of oil sand bitumens
Authors: Dealy John M. 
Published: March 2009

AbstractBitumens extracted from oil sand taken from the Athabasca and Cold Lake regions of Alberta were studied by use of a Mechanical Spectrometer. A heavy crude produced in the Lloydminster area was also studied. Viscosity and first normal stress difference were measured as well as viscoelastic functions. The bitumens are mildly non‐Newtonian in shear and viscoelastic. The behavior is qualitatively similar to that observed in residual asphalts, but it is suggested that the bitumen maltenes form a better solvent for the asphaltenes than in the case with the asphalts. Concentration of solvent, asphaltenes and dispersed water have strong effects on the viscosity. These results are interpreted in terms of molecular aggregation.
Gas chromatographic study of binary diffusion of gases
Authors: Pathak Brajendra K. , Singh Prem C. , Singh Vishwa N. 
Published: March 2009

AbstractA gas chromatographic study of binary diffusion of gas pairs: H2‐Air, H2‐Ar, H2‐O2 and H2‐N2 was conducted at 30°C in a gas chromatograph GCHF‐18 (East Germany) using Gow Mac filament as T.C. detector. Air, argon, oxygen and nitrogen were injected in flowing stream of hydrogen in a stainless steel halical column 4 mm in inside diameter and 3 meters in length. The arrested flow method was used for measuring the variance. The values of diffusion coefficients thus obtained were within −2.47 to +2.43% of the values by Fuller's correlation, 0.12 to 3.38% of the values by correlation of Chapman‐Enskog and −29.99 to −32.94% of the values by Gilliland's correlation.
Vapor‐liquid equilibrium in mixtures of 1,3 dioxolane‐water
Authors: Francesconi Romolo , Castellari Carlo , Arcelli Antonio , Comelli Fabio 
Published: March 2009

AbstractVapor‐liquid equilibrium measurements were carried out with a Stage‐Müller apparatus on mixtures of 1,3 dioxolane‐water at isobaric conditions. Thermodynamic consistency of data was checked, and liquid‐phase activity coefficients were correlated using Wilson's equation, which was applied to various groups of data, each with a restricted range of temperature variation. The parameters δkj of Wilson's equation proved to be independent of the temperature.
Solidification of a low peclet number fluid flow in a round pipe with the boundary condition of the third kind
Authors: Lee S. L. , Hwang G. J. 
Published: March 2009

AbstractThis paper presents a theoretical investigation on the solidification of a low Peclet number fluid flow in the thermal entrance region of a round pipe. The velocity is assumed laminar and fully developed throughout the pipe and the fluid temperature is taken to be uniform at X = −∞. The pipe wall is adiabatic at X ≤ 0 and is cooled convectively at X ≥ 0. The exact solution in the liquid and solid phase are obtained by using the method of separation of variables and constructing two sets of orthonormal functions from the nonorthogonal eigenfunctious at X = ± 0.The solutions including temperature distributions, liquid‐solid interfaces and Nusselt numbers for the parameters, Bi = 20, 4, 0.4, 0.04, Pe = 1, 3, 5, 10, 20, 30, ∞ and the superheat ratios, ξ = (1 − θf)/θf, θf= 0.1, 0.2, …, 0.9 are presented in this paper. The length of ice‐free zone xf corresponding to Pe = ∞ are in excellent agreement with the existing solution.
Mass transfer coefficients in mechanically agitated gas—aqueous electrolyte dispersions
Authors: Hassan Ibrahim T. M. , Robinson Campbell W. 
Published: March 2009

AbstractThe oxygen transfer characteristics of gas‐aqueous electrolyte solution dispersions have been studied in a laboratory‐size, mechanically‐agitated tank equipped with a 6‐flat blade turbine of standard dimensions (DI/T = 1/3). The effects of mechanical agitation power input per unit volume (Pg/V), gas superficial velocity (vS) and aqueous‐phase ionic strength (Γ) upon the overall volumetric mass transfer coefficient (kL a) and the liquid‐phase mass transfer coefficient (kL) are presented. In the range of 0.2 ≤ Γ ≤ 1.2 kmol(ions)/m3, the results of this study indicate that kL increases with increasing Γ is independent of P/V for Pg/V < 2000 W/m3 but decreases with increasing Pg/V above that level and is independent of vs over the range of gas velocities studied. On the other hand, KL a was found to be dependent on all three variables (Pg/V, vg, and Γ).
Continuous phase axial mixing in rotary disk contactors
Authors: Venkataramana J. , Degaleesan T. E. , Laddha G. S. 
Published: March 2009

AbstractThis paper presents a review of important investigations on axial mixing in the continuous phase in rotary disk contactors (RDC) and analyses the various literature data in terms of the flow number (DR N/ue) and a geometry factor Gf. A new model equation has been developed to represent continuous phase axial mixing in the RDC taking into account the factors affecting the recirculation flow within the compartment and the main flow through the compartment in terms of disk‐Reynolds number and modified tube‐Reynolds number respectively. A satisfactory expression for Gf has been obtained on the basis of the present proposed model and analysis of data of available literature and those of the present work, covering laboratory and industrial size columns of 10 different investigators varying from 3.5 cm to 218 cm dia involving 19 different column geometries. The following forms of generalized correlation for continuous phase axial mixing in RDC have been suggested.
On the combinatorial part of the UNIFAC and UNIQUAC models
Authors: Kikic I. , Alessi P. , Rasmussen P. , Fredenslund A. 
Published: March 2009

AbstractThe excess Cibbs energy of liquid mixtures may be predicted using group contribution models (f.ex. UNIFAC and ASOG), or it may be correlated using molecular models such as UNIQUAC. Group contribution models and the UNIQUAC model contain a combinatorial contribution which accounts for size‐ and shape‐effects and a residual contribution which accounts for interactions among groups or molecules. A new expression for the combinatorial contribution is given which yields much improved predictions of the excess Gibbs energy of systems where the residual contribution may be expected to be zero (e.g., mixtures of aliphatic hydrocarbons). It is shown that it is advantageous to incorporate the new combinational expression into future modifications of the UNIFAC model.
The chlorination kinetics of zirconium dioxide in the presence of carbon
Authors: Bicerolu O. , Gauvin W. H. 
Published: March 2009

AbstractThe kinetics of the chlorination of compacted spherical pellets of zirconium dioxide and carbon were studied over a particle temperature range of 1400 to 1950 K. A plasma of pure chlorine generated by an induction torch provided both the high‐enthalpy field and the reacting gas. The influence on the rate of conversion of temperature, chlorine concentration and carbon content were determined experimentally. Based on both experimental and theoretical studies, rate equations were developed.The rate of chlorination was influenced by the separation distance between ZrO2 and carbon particles in the pellets, hence a shrinking‐core model was not obeyed. Instead, a new reaction model was proposed. The experimental results provided adequate information for the selection of optimum conditions with respect to reactor type, temperature and carbon content for an industrial process.
The production of synthetic organic liquids from wood using a modified nickel catalyst
Authors: Boocock D. G. B. , Mackay D. , Franco H. , Lee P. 
Published: March 2009

AbstractExtended batch reactions show that fast‐growing hybrid poplar suspended in water is completely converted to oil and some gas when stirred at 340°C in the presence of Raney nickel. The oil is less viscous when hydrogen is present at sufficiently high pressure. The catalyst is stable up to the maximum time studied (14 hours). The oils typically contain 77% carbon, 7.5‐8.5% hydrogen, and 12‐13% oxygen, have viscosities in the range 5000‐8000 mPa.s and higher heating values of around 35 MJ.kg−1. Nickel produced by reduction of nickel carbonate in situ is also an effective and more practical catalyst.
Intraparticle effects in char combustion steady state analysis
Authors: Srinivas B. , Amundson Neal R. 
Published: March 2009

AbstractA model is developed to study the intraparticle effects of char combustion which incorporates the reactions, C + 1/202 → CO, CO + 1/202 → CO2 and CO2 + C → 2CO with appropriate intrinsic kinetics. Based on some limiting cases a feasibility region, inside which the solution should lie, is developed. In almost all cases the major product is CO with CO2 production 2 to 3 orders of magnitude lower. A maximum of three steady states is observed for the parameters chosen. The combustion rate decreases with increase in particle size and increase in boundary layer thickness. The solution structure depends strongly on the radiation conditions which obtain and on the transport properties inside the particle. The purpose of this study is to determine the effect of intraparticle transport without the confounding effects of other phenomena.
Surface mass transfer processes using peat as an adsorbent for dyestuffs
Authors: Mckay Gordon , Allen Stephen J. 
Published: March 2009

AbstractThe factors affecting the initial rate of Telon Blue (Acid) dye adsorption onto peat have been investigated. The surface mass transfer coefficients for the rate of dye removal from solution have been determined and correlated as the dimensionless mass transfer term Sh/Sc0.33. The function Sh/Sc0.33 has been correlated with respect to four variables, namely, agitation, initial dye concentration, peat particle size range and the temperature of the dye solution. The mass transfer term varies with T5.5, dp0.13, co−1.1 and R.P.M.0.26; consequently temperature has the most pronounced effect on the mass transfer coefficient.
Application of a linear‐three‐phase model to a fluidized‐bed reactor
Authors: Kuhne J. , Wippern D. 
Published: March 2009

AbstractA linear three‐phase model for fluidized bed reactors is proposed. The progress of that model is, that it considers the adsorption of the gas on the solid particles, which will influence the residence time behavior of the system. The solution in the Laplace‐domain is given explicitly, the time‐domain solutions have been approximated by a numerical method. The applicability of the model is shown by means of a 19cm‐diameter fluidized bed.
Direct method for the prediction of expanded bed height in liquid‐solid fluidization
Authors: Ganguly U. P. 
Published: March 2009

AbstractA simple correlation has been developed to predict the expansion of a liquid fluidized bed, consisting of particles varying in size and/or density, which is of the following form:

The relationship is valid over the voidage range from ϵmf to ϵr = 0.96 and gives directly the expanded bed height Le without the determination of the bed porosity ϵe as in existing correlations. The size and density of the solids varied from 30/40 to 72/80 mesh BSS and from 1.67 to 4.33 gm/cm3 respectively while the range of Ret varied from 0.12 to 43.66. The standard deviation for measurements on unicomponent and multicomponent systems has been calculated to be 11.5% and 19.6% respectively at an L/D ratio of 2.0.
On the real molecular weight of polyethylene oxide of high molecular weight in water
Authors: Wolff Claude 
Published: March 2009

AbstractIt is shown that water is close to being a theta solvent for polyethylene oxide which is highly aggregated in this solvent. This result is in agreement with the behaviour observed by hydrodynamic measurements (turbulent drag reduction and concentration and shear dependence of the viscosity). With the molecular weight correction proposed in this work, the onset drag reduction data obtained with Polyox agree well with Virk's theory.
Ozonation of cyanide with emphasis on gold mill wastewaters
Authors: Rowley W. J. , Otto F. D. 
Published: March 2009

AbstractMass transfer ami treatability studies were conducted in a stirred Danckwerts cell to investigate the ozonation of 1) simple cyanide, NaCN, and 2) cyanides found in the barren bleed of Giant Yellowknife Mines Limited. A theoretical analysis of the simultaneous absorption and reaction of ozone in a NaCN solution was used to calculate an overall second order rate‐constant for the reaction with ozone. The order of magnitude value at 23°C is 104 to 105 L/(mol.s). Enhancement factors for the ozonation of the barren bleed are in the range of 80 to 300 for bulk total cyanide concentrations of about 38 to 195 mg/L respectively.Attainable treatment levels for cyanide and thiocyanate and stoichiometric relationships are presented along with an economic assessment for an ozone installation for the Giant Yellowknife Mines Limited case.
A preliminary study of the corrosiveness of methyl fuel/gasoline blends on materials used in automotive fuel systems
Authors: Foulkes F.R. , Kalia R.K. , Kirk D.W. 
Published: March 2009

AbstractA preliminary study was made of the corrosiveness of 15% by volume methyl fuel/gasoline blends on materials conventionally used for gasoline service in automotive fuel systems. The presence of water, salt and air dramatically increased the corrosiveness of the fuel. Of the metals studied, aluminum was relatively unaffected, while copper, brass, steel (types 1181 and 1008), zinc and template all showed signs of corrosion. Non‐metallic samples, particularly expanded polyurethane and Buna‐N. underwent greater attack in the presence of methyl fuel. Conductivity measurements showed that the presence of water and salt in the fuel can cause galvanic corrosion to occur.
Theoretical and experimental studies of confined vortex flow
Authors: Reydon R. F. , Gauvin W. H. 
Published: March 2009

AbstractA study of the air flow characteristics is reported for a vortex chamber 122 cm in diameter consisting of an upper cylindrical section 61 cm high and of a lower conical section 108 cm high. Measurements were made with a five‐channel pressure probe of the radial profiles of tangential and axial velocities, with varying inlet air velocity and axial distance from the top of the chamber. Measurements of the static pressure profiles were made simultaneously. Finally, the angle of flow of the air entering through the single tangential inlet could be adjusted, and its effects on the flow recorded.From these results and from a theoretical analysis, generalized expressions for the tangential velocity profiles were obtained for the two regions of flow, forced‐vortex and quasi‐free vortex, which prevail in a confined vortex chamber, as a function of the entrance air velocity and of the radius at the point considered only. The angle of entering air was found to have no effect on the tangential velocity and only a minor effect on the static pressure distribution. The outlet diameter of the chamber was found to have a large effect on the profile of the axial velocities, reflecting the influence of the chamber static pressure on the latter.
A preliminary experimental investigation into the air‐lift pumping of shear‐thinning suspensions
Authors: Heywood Nigel I. , Michalowicz Robert A. , Charles Michael E. 
Published: March 2009

AbstractIn a recent article(1), it has been postulated that the air‐lift principle may be applied to the raising of liquids or suspensions possessing shear‐thinning Theological behaviour, in order that significant reductions in power requirement may be made compared with conventional mechanical pumping. Using a 41 mm i.d. riser, an experimental study of the raising of highly flocculated kaolin suspensions, at volumetric concentrations ranging from 8.1 to 18.4%, has confirmed that power savings are possible, provided that the isothermal efficiency of the compressor for air injection is substantially greater than mechanical pump efficiencies. Such power savings appear limited to a range of superficial air velocity in the air‐lift riser of 0.25 to 1.25 m.s.−1, and to suspensions containing a relatively high volumetric fraction of flocculated solids.
Rheological comparison of four blow molding resins
Authors: Garcia‐Hejon A. , Dealy J. M. , Kamal M. R. 
Published: March 2009

AbstractFor molten polymers, each theological property provides a different basis for comparison and characterization. This point is illustrated by reference to the results of an extensive testing program involving a series of four commercial blow molding resins, each produced by a different Canadian manufacturer. Three high density polyethylenes were studied at 170°C, while a polypropylene was studied at 190°C. Properties measured included viscosity, first normal stress difference, dynamic viscosity, storage modulus, extrudate swell as a function of time and shear rate, and stress growth functions for both shear and uniaxial elongation.
Effect of heat flux on pressure drop in low pressure flow boiling in a horizontal tube
Authors: Shoukri M. , Yanchis R. J. , Rhodes E. 
Published: March 2009

AbstractThere has been a lack of research specifically examining the effect of heat addition on frictional pressure drop in two phase flow systems. The work presented herein is a result of a series of experiments, using a low pressure steam‐water loop to investigate this effect. It was found that the application of constant heat flux results in a significant increase in frictional pressure drop at certain qualities. It was also found that increasing mass flux or decreasing system pressure shifts the maximum pressure drop towards lower qualities. The observed phenomenon is believed to be the result of liquidvapour interactions at the slug‐annular flow regime transition. This has been confirmed by flow pattern analysis using Mandhane's flow map.
Flow regime boundaries for an interior subchannel of a horizontal 37‐element bundle
Authors: Aly A. M. M. 
Published: March 2009

AbstractA needle contact probe system has been constructed and used to determine flow regime transitions for an interior subchannel in the upper half of a 37‐element horizontal bundle (to include the effect of gravity separation) for adiabatic air‐water flow. For the experimental range considered (up to ˜15.5 K*s−1, 50% quality), five distinct flow regimes were identified. Using the equivalent hydraulic diameter concept and cross‐sectional average superficial velocities, air quality and total mass flux, flow regime maps were constructed. These maps are shown to deviate from pipe flow regime maps. The stratified smooth flow regime was never observed at the lowest flow rate considered due to the periodical disturbance of the flow by the bundle end plates and mid‐plane spacers.
Gasification of western canadian lignite coals
Authors: Heijden S. P. N. Van Der , Verma Arun 
Published: March 2009

AbstractSamples of a typical Estevan lignite coal (empirical formula CH0.81 O0.25 N0.01 S0.003) with a heating value of 16.713 MJ/kg were gasified with air only and air/steam mixtures at near atmospheric and high pressures up to 6 MPa.The carbon content of ash/char residues of the gasification reactions varied from 1.2% for air/steam reactions and was in the 16‐53% range for reactions using air only, For all experiments the end point was clearly indicated by a rapid change in oxygen concentration in the gas samples.Plots of the fractional conversion of carbon as a function of time, showed high initial reaction rates as the volatile matter in coal is gasified. The rates diminish as the carbon is being consumed.The heating values for the gas samples collected during each run showed a large correlation with the methane content of the sample.