bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined free‐and‐forced convection: I. Heat transfer in aiding flow
Authors: Brown C. K. , Gauvin W. H. 
Published: June 2009

AbstractA study of the rate of heat transfer to air at low velocities was performed in a heated stainless tube, 4.42‐in. inside diameter and 102‐in. long. The air flowed upward through the tube, under which conditions the buoyancy forces aided the forced flow. The investigation covered a Reynolds number range from 385 to 4,930, and nominal wall temperatures of 100, 500 and 950°C. For laminar aiding flow, the local Nusselt number could be correlated with (NGr/NRc). For turbulent flow, the local Nusselt number was correlated with the Grashof number independently of the axial position for fully‐developed flow, and agreed with published data for pure free convection.
The effect of noise on process optimization
Authors: Heaps H. S. , Wells R. V. 
Published: June 2009

AbstractThe effect of noise on several methods of process optimisation is discussed. The optimising procedures include the gradient method, circle method, random search, and interpolation. Illustration is made with respect to two particular response surfaces in the presence of noise. The first surface is strongly unimodal; the second contains a sharp curved ridge which rises slowly to a single maximum. A technique is suggested for application to general unimodal response surfaces in the presence of noise.
Kinetics of gas‐solid non‐catalytic reaction
Authors: White Donald E. , Carberry James J. 
Published: June 2009

AbstractAnalytical relationships are derived for non‐catalytic first order diffusion influenced reaction between a gas and solid sphere of dimension which varies with extent of reaction. Bulk mass transport and diffusion through the product layer are assumed to occur in series with chemical reaction. The limiting case of totally volatile product is also treated. The fluid phase transport coefficient is incorporated as a general function of particle size and fluid velocity. The extent of reaction‐time relationship is more significantly affected by particle size change during reaction than by the functionality governing the bulk mass transport coefficient variation with geometry and velocity.
On corrective factors for project uncertainty
Authors: Rudd Dale F. , Watson Charles C. 
Published: June 2009

AbstractA common method of accounting for uncertainty in an engineering project is to assign a minimum acceptable rate of return on capital investments. This minimum rate of return is assigned in a rather arbitrary way according to the expected risk in the project. In this paper we introduce the concepts of statistical decision theory and show how the minimum rate of return can be estimated in terms of uncertainty in sales income, project life, investment, manufacturing costs, etc.
Comparison of gas‐liquid contacting trays
Authors: Cej R. P. , Furter W. F. 
Published: June 2009

AbstractThe performances of four types of distillation tray of current industrial importance were compared in a common environment under similar hydraulic conditions. The four types investigated were the bubble‐cap, sieve, Turbogrid, and ripple trays. A single tray of each type, of representative dimensions, was used. The four trays were compared in regard to hydraulic characteristics, and also in regard to mass transfer efficiencies based on composition changes occurring in the gas phase during gas absorption. The comparison was carried out at relatively low vapor loadings in order to avoid excessive entrainment and channelling.
Heat transfer to agitated non‐newtonian fluids
Authors: Carreau Pierre , Charest Guy , Corneille Jean L. 
Published: June 2009

AbstractHeat transmission to agitated non‐Newtonian liquids in a jacketed vessel has been studied. Heat transfer tests were conducted under unsteady‐state conditions with pseudo‐plastic solutions (behavior index range: 0.343 to 0.633).For a generalized Reynolds number ranging from 100 to 5000, two correlations were found:

The use of a generalized Sieder and Tate number resulted in an equation combining both heating and cooling data with a somewhat higher mean deviation (19.3%):
Fluid friction and heat transfer in plain, concentric annuli
Authors: Ratkowsky D. A. 
Published: June 2009

AbstractEach of the two friction factors in an annulus is defined in terms of the average kinetic energy of the fluid in the region between the radius of maximum velocity and the appropriate wall. These friction factors thus defined can be uniquely correlated against corresponding Reynolds numbers. The correlation is excellent for the outer portion of flow for all values of the radius ratio r1/r2, but not as good for the inner region of flow when r1/r2 is small. Applying the Colburn analogy, inner and outer wall j‐factors are similarly correlated with the same degree of accuracy.
The electrical conductivity of fluidized beds of coke and graphite up to 1200°
Authors: Graham W. , Harvey E. A. 
Published: June 2009

AbstractNitrogen‐fluidized beds of petroleum coke and graphite were heated by applying an a.c. voltage to electrodes submerged in the bed. Bed resistivities, calculated from the voltage and power input required to maintain a constant temperature, show a similar decrease in resistivity, for both materials, with increasing temperature up to 600°C., however, at about 600°C. the resistivity of graphite beds continues to decrease while that of coke beds goes through a minimum and then increases.This was attributed to arc formation at the contacts between coke particles when the applied voltage exceeds a critical value. Similar behavior was not observed for graphite as the operating voltage never exceeded the critical value.
Thermal separation of coal‐oil suspensions in a fluidised bed
Authors: Round G. F. , Kruyer Jan , Hodgson G. W. 
Published: June 2009

AbstractA series of experiments were made on the thermal separation of various mixtures of coal in oil using a fluidized bed reactor. The majority of experiments were carried out on a mixture of 30% w/w Edmonton coal in 70% w/w Leduc crude oil in a temperature range of 700–900°F. The products of the reaction were a char, an oil and a gas. At temperatures above 700°F. the solid particles became dry and free‐flowing; no agglomeration or channelling in the bed was apparent. An increase in reactor temperature in the 700–900°F. range decreased the amount of residual oil on the char from about 2% to 0.1% at the same time the heating value of the char rose from 11,900 to 12,600 Btu/lb. Carbon residue of the product oil was substantially less than that of the original oil, the reduction being about 50% in the case of Leduc oil and 75% for Lloydminster oil.
Correlation of pressure gradients for the stratified laminar‐turbulent pipeline flow of two immiscible liquids
Authors: Charles M. E. , Lilleleht L. V. 
Published: June 2009

AbstractThe parameters introduced by Lockhart and Martinelli to correlate pressure gradients accompanying the flow of gas‐liquid mixtures in horizontal pipes have been found to be useful in correlating data for the stratified flow of two immiscible liquids in the laminar‐turbulent regime. Curves through liquid‐liquid data available from three different sets of experiments, though being significantly displaced from the Lockhart‐Martinelli curves for gas‐liquid systems, represent the data with a maximum deviation of approximately 24%.
Experimental study of natural convective heat transfer in a non‐newtonian fluid: Part II. Horizontal plate
Authors: Reilly I. G. , Tien Chi , Adelman Maurice 
Published: June 2009

AbstractExperimental data of natural convection heat transfer from a heated horizontal plate, both facing upward and downward, to a non‐Newtonian fluid are reported. Empirical expressions essentially similar to those developed for the vertical plate case are obtained which correrlate the data with reasonable accuracy.
The mixing of solid particles in a fluidized bed
Authors: Jinescu Gheorghitza , Teoreanu I. , Ruckenstein E. 
Published: June 2009

AbstractIn this paper a new experimental method, based on the freezing of the fluidized bed by the aid of paraffin wax is used for the determination of the diffusion coefficient of the solid particles. The experimental diffusion coefficients are compared with those given by a theoretical equation. In order to explain the time and spatial dependence of the experimental diffusion coefficient a cinematographic study supplemented by visual observations is also made. One concludes that for small tube diameters a circulation motion of the solid particles takes place which is responsible for the mentioned effect.
Surface diffusion in microporous media
Authors: Hwang Sun‐Tak , Kammermeyer Karl 
Published: June 2009

AbstractThe surface diffusion of He, Ne, H2, Ar, O2, N2 and CO2 through Vycor microporous glass was analyzed theoretically and experimentally in the low pressure range as a function of temperature. A statistical‐mechanical treatment was carried out in terms of partition functions to derive a general equation of surface flow. It was possible to separate the surface diffusion from the total flow using a simplified working equation. The conventional method which assumes that there is no adsorbed flow for helium should be discarded, because the fraction of surface diffusion for helium ranges from 0.133 to 0.247. It is also illustrated how to predict the permeability of a new gas for the same porous medium.
Particle trajectories and terminal velocities in vertically oscillating fluids
Authors: Houghton Gerald 
Published: June 2009

AbstractThe trajectories and terminal velocities of particles in vertically oscillating fluids have been studied by obtaining analytic and numerical solutions to the nonlinear Langevin equation representing a superposition of forces arising from particle acceleration, displaced fluid acceleration, buoyancy and particle‐fluid drag as represented by an nth‐power drag law. In vibrating fluids the directional particle velocities are found to be lower than in stationary fluids for drag exponents n > 1 and correspondingly higher for 0 < n < 1. The engineering significance of the results is discussed in relation to hold‐up, separation and transport phenomena in vertically oscillating multiparticle‐fluid systems.
The expansion/contraction behavior of laminar liquid jets
Authors: Oliver D. R. 
Published: June 2009

AbstractAn apparatus for measuring the thrust of liquid jets is described and the effect of surface tension on jet thrust discussed in detail.Whether the liquids used are nominally “Newtonian” or “viscoelastic”, there is a consistent trend in the expansion‐contraction behaviour. This is explained on the grounds that the fluids, from ethyl alcohol and glycerol on the one hand to poly (ethylene oxide) solutions on the other, possess appreciable elastic properties. Thrust measurements using short capillaries support this contention.At very low Reynolds numbers the jet thrusts are unusually high; it is suggested that this results from a purelyviscous phenomenon.
Reduced state correlations of the enskog modulus for gases and liquids
Authors: Veeramani Hariharan , Thodos George 
Published: June 2009

AbstractThe Enskog modulus, bρ x, has been subjected to a generalized treatment to develop reduced state correlations for nonpolar and polar substances that exhibit hydrogen bonding. These correlations present relationships between 1 + bρx and ρR, the reduced density.For nonpolar substances, the PVT data of argon, nitrogen, methane, ethane, and carbon dioxide were used for the development of these relationships, which were found to depend on zc, the critical compressibility factor. PVT data for ammonia, methyl alcohol, and water yielded a different correlation, which is applicable to polar substances which exhibit hydrogen bonding. These relationships were found to depend on the parameter, β = (Tb‐Tm)/M, which quantitatively describes the extent of hydrogen bonding for polar compounds.
The flow of suspensions through tubes: V. Inertial effects
Authors: Karnis A. , Goldsmith H. L. , Mason S. G. 
Published: June 2009

AbstractThe behavior of particles undergoing Couette and Poiseuille flows at rates when inertial effects become significant was investigated.The rotation of rigid particles was similar to that in the Stokes flow regime, except for a drift of cylinders to limiting rotational orbits corresponding to the maximum energy dissipation.In Poiseuille flow, rigid particles migrated to an equilibrium radial position which depended on the density difference of two phases, the directions of sedimentation velocity and flow, and the ratio of particle to tube radius. Neutrally buoyant deformable particles always migrated to the tube axis.In concentrated suspensions a plasmatic layer developed near the tube wall as a consequence of radial migration. The formation of this layer modified the velocity profile and caused a reduction in the apparent viscosity coefficient.
Mass transfer from bubbles in cocurrent flow
Authors: Lamont J. C. , Scott D. S. 
Published: June 2009

AbstractAn experimental study has been made of liquid phase mass transfer from bubbles travelling cocurrently with liquid in a horizontal pipe. A simple model of the process based on streams of spherical bubbles has been developed and solved in the form of fractional absorption as a function of dimensionless groups. The derivation of and results obtained from this model are presented and explained. Experimental absorption rates measured in turbulent liquid flow over very wide ranges of bubble frequencies support the predictions of this model.A very effective bubble‐frequency counter has also been developed capable of counts as high as 1600/min.
The characteristic dimension in scraped surface heat transfer
Authors: Bott T. R. , Romero J. J. B. 
Published: June 2009

AbstractPrevious published work on scraped surface falling film heat exchangers has used the tube diameter as the characteristic dimension. The present investigation confirms that in such equipment the liquid is carried as a fillet, roughly triangular in shape in front of the blades. Using an equivalent diameter based on flow area of the fillet and the length of the are in contact with the transfer surface, a correlation based on earlier results is developed which is independent of tube diameter, except in defining the rotary inertia forces. The refined correlation is:—
An evaluation of the pneumatic transport reactor
Authors: Yannopoulos J. C. , Themelis N. J. , Gavvin W. H. 
Published: June 2009

AbstractIn a pneumatic transport reactor, a dilute suspension of the reacting solid particles is conveyed by the gas stream through the reactor. The system is characterized by very short particle residence times. The relative flow rates of gas and solids are determined by the thermodynamic and kinetic requirements of the reacting conveyed systems.Design considerations for co‐current gas and solids flows are presented and a comparison between co‐gravity and counter‐gravity flow reactors is discussed for the case of iron ore reduction by hydrogen. Kinetic data from single particle studies have been used to predict the performance of a pilot‐scale reactor.
A simulation and parametric study of four existing multi‐component distillation columns
Authors: Petryschuk W. F. , Johnson A. I. 
Published: June 2009

AbstractThe Θ‐method and block‐relaxation method of solving The non‐linear set of algebraic equations which describe the leady‐state behavior of standard distillation columns are compared.The results from the mathematical models are compared with actual plant performance of a depropanizer, debutanizer, de‐ethanizer, and ethane‐ethylene splitter. Column section efficiencies are tabulated. A parametric study of the variation of feed condition, reflux condition and flow, and feed tray location was made on these columns and the responses of the key component concentrations have been mapped.Such a study permits improvement of current plant operation. Its use for design of more efficient columns and arranangements is indicated.
Analytical solutions to the semi‐discrete form of the conduction equation for non‐homogeneous media
Authors: Darsi C. R. , Quon D. 
Published: June 2009

AbstractThe partial differential equation describing transient conduction (or diffusion) in non‐homogeneous media may be approximated by a set of first order linear ordinary differential equations if the derivatives involving the space variables are replaced by finite difference expressions. A general method of obtaining a closed form solution of these equations is presented, using some operational methods of linear algebra. The solution is given in terms of a matrix, which describes the spatial distribution of physical properties in the media, and vectors describing the initial and boundary conditions.
Momentum and heat transfer characteristics of liquid‐liquid dispersions in turbulent flow
Authors: Legan R. W. , Knudsen J. G. 
Published: June 2009

AbstractThe momentum and heat transfer characteristics of unstable, liquid‐liquid dispersions flowing turbulently in a circular tube were investigated. Two mineral oils, a light oil with viscosity of 15 centipoise, and a heavy oil with viscosity of 200 centipoise were used as the dispersed phase while the continuous phase was tap water. At room temperature only, the relative fluidity of the dispersion follows the relation

At Reynolds numbers above 60,000 the heat transfer coefficients of all dispersions studied follow the relation

where the Prandtl number is that of the continuous phase and the Reynolds number is based upon the viscosity of the dispersion. All properties are evaluated at the film temperature.
Some observations on heat transfer to agitated liquids
Authors: Appleton W. T. , Brennan W. C. 
Published: June 2009

AbstractHeat transfer coefficients for agitated liquids in a flat‐bottomed vessel equipped with a heating coil have been measured over wide ranges of Prandtl and Reynolds numbers in order to examine the effect of coil surface, impeller design and coil geometry. The study of impellers included a comparison of flat‐bladed and pitched‐bladed agitators. Helical and baffle coil geometries were tested using smooth, knurled and finned tube surfaces. For all systems studied the Reynolds number exponent was observed to be dependent on viscosity. The data for finned tubes indicated higher transfer rates due to increased surface area and wall‐turbulence.
Discrimination between two rival models through nonintrinsic parameters
Authors: Mezaki R. , Kittrell J. R. 
Published: June 2009

AbstractIn analyzing data from heterogeneous reactions, it is often necessary to quantitatively compare the relative ability of two rival models to fit the data. For Hougen‐Watson models, techniques exist for comparing this degree of fit for low conversion data; a method is suggested here for making quantitative comparisons using high as well as the low conversion data. Once estimates of the parameters in the two models are obtained, the method may be applied by a one‐variable regression analysis. An example is presented illustrating the advantages of using all the conversion data in discriminating between two rival models.
Heat transfer limitations on nuclear reactor fuel elements
Authors: Rogers J. T. 
Published: June 2009

AbstractLimitations on heat transfer rates on fuel elements in Canadian heavy‐water‐moderated reactors are examined.With organic coolant in simple flow geometries, heat fluxes are limited by departure from nucleate boiling, (DNB); in simulated fuel bundles the failure mechanism can be either localized DNB, or coke‐out, the formation, deposition and rapid growth of coolant decomposition products on heated surfaces.With boiling light water coolant, critical heat flux (CHF) is caused by DNB at low qualities and by dry‐out at higher qualities. Parameters governing CHF in tubes and annuli are fairly well established. Data for fuel bundles are becoming available. Methods of increasing CHF and of rationally setting margins of safety on CHF are being developed.
The determination of mass transfer coefficients and interfacial areas in gas‐liquid contacting systems
Authors: Dillon G. B. , Harris I. J. 
Published: June 2009

AbstractExperimental studies of absorption without and with reaction in a single orifice bubble contactor and on a sieve plate have been used as the basis of interfacial area determinations. Results obtained were compared with values obtained by other techniques. The limitations of the method are discussed.
Adiabatic homogeneous bubbly flow in horizontal pipes
Authors: Hvey C. T. 
Published: June 2009

AbstractThe usual one dimensional method of analysis based upon the equations of continuity, energy and momentum is applied to the flow of homogeneous bubbly liquid‐gas mixtures in horizontal pipes. The analysis results in a set of equations which are adequate insofar as they are able ro explain known phenomena of the flow. It is shown that the concept of the Mach number, applied to bubbly pipe flow, is physically meaningful in the same way as it is in gas dynamics and that the condition, Mach number equal to one represents a realistic criterion for flow choking. A friction‐length formula is derived and verified experimentally.
Surface adsorption and the effect of column diameter in the continuous foam separation process
Authors: Wood R. K. , Tran T. 
Published: June 2009

AbstractFoam separation has been investigated as a technique for removing ethylhexadecyldimethylammonium bromide, a cationic surfactant, from dilute solutions. An ideal foam model has been used to determine the surface excess accumulated at the solution‐air interface and to predict the foam and drain concentration in a continuous foam separation process. It was found that the model was valid only under conditions of good drainage and perfect foam stability.An increase in column diameter for a feed of constant composition and supplied at a constant rate increased the concentration of the surfactant in the overhead stream. This highly desirable effect was accompanied by an increase in the drain rate. The results indicate that an increase in column diameter had an entirely beneficial effect on the efficiency of the separation.
Heat transfer studies in a climbing film evaporator Part II: Heat transfer regions
Authors: Gupta A. S. , Holland F. A. 
Published: June 2009

AbstractThere are three sections in an evaporator tube; liquid heating, foam and climbing film. A technique is presented for estimating the lengths of these three sections and the overall heat transfer coefficients in each of them.The lower the liquid feed temperature, the longer the liquid heating length. The length of the foam section does not depend on the liquid feed temperature. In these studies it was estimated to be more than half the length of the evaporator tube. Only at the higher liquid feed temperatures was a climbing film found to exist.
Contrǒle anticipé de la température au moyen d'une calculatrice analogique
Authors: Cloutier L. , Girard J. 
Published: June 2009

AbstractUn montage spécial a servi à l'étude du contrǒle de la température, dans un réservoir, par action anticipée. On a utilisé la température de l'alimentation au réservoir pour actionner le contrǒleur. Une vérification de la température à la sortie du réservoir avait pour but d'obvier au fait que des demandes imprévues pouvaient survenir au‐delà du point de contrǒle à l'entrée.Les résultats obtenus indiquent que le contrǒle par action anticipée avec vérification à la sortie représente une certaine amélioration sur le contrǒle en boucle fermée. Une telle amélioration serait supérieure si les constantes de temps du procédé et de l'élément final de contrǒle étaient du měme ordre de grandeur.