bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass, heat, and momentum transfer in the flow of gases past single spheres
Authors: Yen Yin‐Chao , Thodos George 
Published: June 2004

AbstractThe transfer of mass, heat, and momentum past a single sphere, 2.02 in. in diameter, was experimentally investigated for the turbulent flow of air between NRe = 1,750 and NRe = 8,922. The data resulting for the vaporization of water from the spherical surface verify the existence of the analogy between mass and heat transfer.Measurements were made to account for the total drag and form drag of the sphere. The total drag was obtained by directly accounting for the force exerted, while the form drag was determined from static pressure measurements around the surface of the sphere. The resulting friction factors for total drag f and for form drag fp were found to be of the same order of magnitude, thus making it impossible to account for the friction factor due to shear drag at these Reynolds numbers. Consequently it is not possible to determine if the analogy between mass and heat transfer can be extended to include the transfer of momentum for flow past single spheres at these conditions, although the results of this study cast considerable doubt on such an extension of this analogy.
Mass transfer to particles: Part II. Suspended in a pipeline
Authors: Harriott Peter 
Published: June 2004

AbstractMass transfer coefficients are reported for particles of boric acid and benzoic acid dissolving in water in a 2‐in. pipeline. For water velocities of 1 to 4 ft./sec. the coefficients are 1.2 to 2 times the values predicted for freely falling particles. The coefficients are slightly less than those obtained in agitated tanks at the same power per unit volume.
Thermodynamic properties of polar gases in the dilute phase
Authors: Eubank P. T. , Smith J. M. 
Published: June 2004

AbstractA procedure is proposed, based in part on theory and in part on experimental data, for predicting the effect of polarity on the thermodynamic properties of polar, organic gases in the dilute phase. This correlation was used to predict compressibility factors Z, and the change of enthalpy with pressure, in the vapor phase.By use of this correlation the computed compressibilities indicated an average absolute deviation of 1.0% from available experimental data, which includes reduced pressures up to 0.9 and temperatures to 1.0. Similar comparisons were made for the effect of pressure on enthalpy.
Bubble rise in a packed bed saturated with liquids
Authors: Gorring Robert L. , Katz Donald L. 
Published: June 2004

AbstractExperimental data were determined for drag coefficients on fluid bubbles rising in a saturated packed bed and in clear liquids. Air and benzene were used to form bubbles in glycerine solution, water, and normal heptane. One‐inch diameter glass spheres in hexagonal, random, and cubic packings constituted the bed. The range in Reynolds number was from 0.1 to 1,000. It was found that the drag coefficients in the hexagonal and random arrays were from two to three times those in clear liquids, while the drag on bubbles rising in cubic packings was the same as that for clear liquids. The method of correlation involved the use of the minor diameter in the drag coefficient and the major diameter in the Reynolds number. This innovation improved the correlation for bubble rise in clear liquids.
Gas mixing in a square duct: II
Authors: Miller Eugene , Wohl Kurt 
Published: June 2004

AbstractInstantaneous shadow photography is used to study the mixing of air flowing in a 2‐in. square duct with a secondary stream of carbon dioxide entering sidewise from an orifice. Mixing is described in terms of four mixing parameters measured from the shadow photographs, penetration distance, bulk mixing distance, macromixing distance, and the quality of micromixing, as a functon of sidestream: mainstream mass velocity and volume flow ratios, main duct velocity, and the average orifice shroud velocity component parallel to the air flow in the main duct.The first three parameters are reported quantitatively as a function of the variables mentioned. The latter parameter is reported semiquantitatively by means of a scale of grading the micromixing which describes the condition of the schlieren at arbitrary duct lengths downstream from the entrance of the gases. Comparisons are made with previous results from studies of the secondary gas entering sidewise from a tube.Orifice discharge coefficients are correlated as a function of the orifice diameter, orifice Reynolds number, main duct velocity, and orifice shroud velocity. These are presented to aid in the description of the mixing and to be used in the design of similar mixing configurations.
The effect of column length on separation in thermogravitational thermal diffusion columns
Authors: Crownover Carl F. , Powers John E. 
Published: June 2004

AbstractA series of experiments was designed to test the phenomenological theory of thermogravitational thermal diffusion columns by obtaining data on the steady state separation and approach to equilibrium in a batch column as a function of column length. Data were obtained on the separation of an equimolar n‐heptane‐benzene solution at five different values of column length varying from 14.5 in. to 6 ft. All measurements were made in one concentric cylinder column in which the effective length was varied by controlling the liquid level in the annulus. Helium gas was used to displace the air in the annulus above the liquid in order to provide even temperature distribution throughout the column. The data were found to substantiate the effect of length predicted by application of the phenomenological theory and to be in very good agreement with other aspects of the theory.
Design and evaluation of a new body for falling cylinder viscometers
Authors: Lohrenz John , Kurata Fred 
Published: June 2004

AbstractA new body with stabilizers removed from the cylindrical section was designed for falling cylinder viscometers. Experimental data to evaluate the new body were obtained with gases and liquids at varying temperatures and pressures.Experimental results showed improved agreement with a theoretical model that assumes laminar flow friction along the cylindrical portion of the body and negligible additional frictional effects. Effects of temperature and pressure were accurately predicted by this theoretical model. The data were correlated on an improved viscometer plot.The advantage of the new body design was a negligible frictional effect of the stabilizers. The entrance‐exit frictional effect was evaluated from the experimental data and correlated on a friction factor plot. Fluid flow in the annulus remained laminar throughout this study. The results of this investigation allow an improved prediction of the falling‐cylinder viscometer constant.
Pore diffusion in silver catalysts
Authors: Masamune Shinobu , Smith J. M. 
Published: June 2004

AbstractDiffusion rates were measured at atmospheric pressure and room temperature for helium and nitrogen in pelleted silver catalysts. Pellets were prepared from three silver salts giving different micropore characteristics. The data showed that the diffusion was of the bulk type and that the micropores had no effect, indicating that mass transfer was predominantly in the macropore region. For each kind of material data were obtained for five pellet densities corresponding to macropore volume fractions from 0 up to 0.7.Effective diffusivities and labyrinth factors ψ were evaluated and found to increase with macropore porosity. The linear relationship between ψ and void fraction proposed by Buckingham for diffusion through soils fitted the data at high void fractions. A generalized form of the Maxwell equation containing three constants was derived. A single‐constant form of this expression agreed reasonably well with the measured results over the entire range of macropore volume fraction.
Transport characteristics of suspensions: Part IV. Friction loss of concentrated‐flocculated suspensions in turbulent flow
Authors: Thomas David G. 
Published: June 2004

AbstractTurbulent flow friction factors were determined for flocculated suspensions of thoria, kaolin, and titania in tubes 1/8‐ to 1‐in. diameter. The non‐Newtonian laminar flow data were arbitrarily fitted with the Bingham plastic model. With this model the range of yield stress values was 0.018 to 1.39 lb.f/sq. ft., with a maximum ratio of coefficient of rigidity to viscosity of suspending medium of 11.1. The volume fraction solids were varied from 0.042 to 0.23.Two types of behavior were observed depending on the value of the yield stress. For yield values less than 0.5 lb.f/sq. ft. the turbulent friction factors were always less than those for Newtonian fluids but tended to approach the Newtonian values as the Reynolds number was increased. For yield values greater than 0.5 lb.f/sq. ft. the friction factors were again less than those for New‐tonian fluids but tended to diverge from the Newtonian values as the Reynolds number was increased. Both sets of data were correlated with the Blasius relation with the coefficient and exponent given in terms of the laminar flow properties und the volume fraction solids.
Transport properties of gases in porous media at reduced pressures with reference to freeze‐drying
Authors: Harper John C. 
Published: June 2004

AbstractTheory is outlined relative to the effect of pressure on permeabilities and thermal conductivities of gases in porous solids in the slip flow and free‐molecule flow regions, and experimental results are reported for several freeze‐dried food materials. Mean pore diameters for the porous materials calculated from permeability data were about 100 μ and were in agreement with microscopic observations. Thermal conductivities followed the predicted behavior of a constant value at high pressures, with a gradual decrease to another constant value at very low pressures. The results show that the usual operating pressure range of freeze‐dryers (0.1 to 1.0 mm. Hg) corresponds to the transition region between slip flow and free‐molecule flow.
An analytical study of heat transfer in laminar‐turbulent transition flow between parallel plates
Authors: Gill William N. , Lee Shaw Mei 
Published: June 2004

AbstractWith the results of a modification of Prandtl's mixing length theory, heat transfer in laminar‐turbulent transition flow is considered. An analytical study was made to obtain the eigenvalues, Nusselt numbers, and temperature distribution for transition region flows between constant temperature parallel plates. Reynolds numbers ranging from 4,800 to 43,000 and Prandtl numbers from 0.01 to 100 were investigated. Six to nine eigenvalues were obtained for each set of parameters. These values were used to compute local Nusselt numbers and thermal entrance lengths. The practicality of four numerical methods used for solving the associated Sturm‐Louville system is discussed.It is shown how heat transfer effects change in the transition region. As expected, these changes are more rapid for higherNPrfluids where eddy diffusion is most effective.
Thermal and material transfer in turbulent gas streams: One‐inch spheres
Authors: Venezian Emilio , Crespo Manuel J. , Sage B. H. 
Published: June 2004

AbstractAs part of a study of the effect of conditions of flow upon macroscopic and local thermal and material transport from spheres, an investigation was made of the macroscopic and local transport from a silver and a porous sphere each 1 in. in diameter. The transport was measured in a turbulent air stream at Reynolds numbers up to 7,500, and the apparent level of longitudinal turbulence of the stream was varied between 0.013 and 0.15. In the case of the porous sphere the thermal and material transport were evaluated for the evaporation ofn‐octane.The results indicate that the macroscopic Nusselt number is substantially larger for combined thermal and material transport than for thermal transport alone. The local Nusselt number varied by a factor of 5 around the silver sphere from stagnation to separation.
Absorption of ammonia by acetic acid solutions
Authors: Dhillonn Sharanjit S. , Perry R. H. 
Published: June 2004

AbstractAbsorption accompanied by rapid, second order, irreversible reaction was studied in disk column. The chemical system used involving absorption of ammonia by acetic acid has not been reported on before. Results confirm the prediction of two‐film and unsteady state theories for this class of two phase reaction; that is the liquid film absorption coefficient is a linear function of ratio of acid normality to interfacial concentration of ammonia. At high acid concentrations the liquid film resistance disappears. In preliminary studies an abrupt transition between laminar and turbulent liquid flow was noted, and as predicted by the unsteady state theory the liquid film coefficient in the laminar region was proportional to the 0.33 power of the liquid flow rate.
Nonequilibrium thermodynamic theory for concentration profiles in liquid extraction
Authors: Hennico Alphonse , Vermeulen Theodore 
Published: June 2004

AbstractThe pattern or profile of concentration change in each of the two countercurrent streams, within a packed extraction column involving a three‐component system, is generally assumed to follow either branch of the mutual‐solubility curve for the system. In the work reported here such concentration profiles have been computed for an idealized extraction. The results show that the raffinate will usually be carried into a metastable condition inside the equilibrium curve, but the extract composition remains appreciably outside the equilibrium curve.In the calculations mass transfer coefficient ratios are held constant at any one steady state condition of operation (called a run), but are varied in different runs, in order to determine the direction and magnitude of their effects. A modified activity‐gradient, derived both for molecular diffusion and for penetration‐theory conditions, is postulated to govern mass transfer and is used in place of the usual concentration driving potential. Solute depletion, mainly, is found to explain the result for the raffinate phase in much the same way that temperature lowering leads to supersaturation in binary solutions. Solute enrichment is the cause of the extract‐phase behavior.
Ignition limits for pilot‐stabilized high‐velocity, turbulent, butane‐air mixtures at low pressure
Authors: Griskey Richard G. , Archer David H. 
Published: June 2004

AbstractLimiting velocities were determined by finding the composition at which the flame first spread into the unburned gases for a given velocity and turbulent intensity. These composition were represented by intersections of curves of flame widths at certain combustion chamber positions plotted vs. composition.
The critical temperatures of multicomponent hydrocarbon systems
Authors: Grieves Robert B. , Thodos George 
Published: June 2004

AbstractThe critical temperature of any multicomponent hydrocarbon system may be established solely from the normal boiling points of the pure constituents. Such mixtures may include normal paraffins, isoparaffins, olefins, acetylenes, naphthenes, and aromatics and may contain an unlimited number of components.An expression has been developed for the prediction of the critical temperatures of mixtures and has been tested on fifty‐five hydrocarbon systems containing from two to five components. For 208 binary mixtures the deviations from reported values were calculated, and the maximum deviations resulting from each system were averaged for the forty‐one binary systems to produce an average maximum deviation of 0.91% based on degrees absolute. For twenty‐eight multicomponent mixtures reported for nine ternary, two quaternary, and three quinary systems the average deviation was 1.03%.This method presents a simple and accurate means of establishing the critical temperature of any multicomponent hydrocarbon mixture as long as the ratio of the normal boiling points of the heaviest and lightest components present in the mixture does not exceed the prescribed limits.
Concentration fluctuations in a stirred baffled vessel
Authors: Manning F. S. , Wilhelm R. H. 
Published: June 2004

AbstractA stirred vessel is maintained in a quasisteady state by continuously introducing water and a conductive tracer solution and continuously removing the resulting mixture by overflow. Detailed properties of the system are elucidated by measuring tracer concentration changes with a conductivity probe in a volume element of the order of 0.3 cu. mm. By the use of suitable electronic equipment the following statistical concentration parameters are measured in experiments with three diameters of flat‐bladed turbines and with a tenfold range of rotational speed: temporal mean, total root‐mean‐square fluctuation, spectral distribution of fluctuations, and Eulerian micro time scale. Results are interpreted in terms of behavior of time‐average and fluctuation measures in three regions, the generation region within the impeller volume, the decay region which starts in the horizontal fluid sheet issuing from the impeller, and the recirculation flow region in the vessel.Generation of concentration fluctuations within the confines of the impeller is described in terms of a model involving gross mixing, without significant decay, in the wake of each flat blade. Distributions of mean and fluctuating concentrations are suggested to provide a measure of uniformity in the vessel as a whole. The former, in particular, was remarkably constant throughout the vessel.
The viscosity of ammonia: Experimental measurements for the dense gaseous phase and a reduced state correlation for the gaseous and liquid regions
Authors: Shimotake Hiroshi , Thodos George 
Published: June 2004

AbstractThe unsteady state flow of ammonia gas has been investigated to determine its viscosity at elevated pressures and moderate temperatures. This was accomplished in an experimental unit of the transpiration type which was calibrated with nitrogen, for which viscosity data at high pressures were available in the literature. To obtain the viscosity at the operating conditions the basic differential equation for the unsteady state flow caused by the experimental procedure was developed and solved with an IBM‐650 digital computer.Experimental runs were conducted for pressures ranging from 250 to 5,000 lb./sq. in. and temperatures from 100° to 200°C. This information has been used to establish the viscosity of ammonia at these dense phase conditions for which no viscosities had been previously reported. These values were used to develop a unique correlation between the residual viscosity and the density. This correlation then enabled the determination of ammonia's viscosity at the critical point μc = 2,395×10−5 centipoises.The Enskog viscosity equation has been used with the values resulting from this study and PVT data for ammonia to develop a relationship for the probability of nearness. This relationship enables viscosities to be calculated for densities up to 0.450 g./cc. which are in close agreement with the experimental values.
Deviation from the inverse‐thickness relation in gas‐metal permeation
Authors: Phillips J. R. , Dodge B. F. 
Published: June 2004

AbstractThe permeation rate of hydrogen through cylindrical membranes of type 321 stainless steel was determined under a wide range of conditions. The pressure was varied from 0.1 to 30.0 atm. and the temperature from 300° to 800°C. Four permeation membranes were used with wall thicknesses of 0.0252, 0.1003, 0.1011, and 0.2475 cm.The permeation rate was found to deviate from the square‐root‐of‐pressure and inverse‐thickness relations predicted by the Richardson equation. Slow surface reactions are considered to be the cause of the observed deviations. The permeation data were correlated by a semiempirical interfacial resistance model.Permeation rates were observed to increase with time of membrane exposure to hydrogen. It is believed this resulted from changing surface activity.
Perturbation velocities in gas‐liquid partition chromatographic columns
Authors: Stalkup Fred I. , Deans H. A. 
Published: June 2004

AbstractThe characteristic velocities in binary and particular ternary cases allow straightforward calculation of equilibrium partition coefficients for components present in both flowing and fixed phases. It is shown in the case of a general N‐component flowing phase that N‐1 characteristic velocities arise. In theory N‐1 equilibrium partition coefficients can be obtained from measurements of these velocities. It is also shown that radioactive tagging of one component provides a distinct characteristic velocity, which can be used either to obtain the Nth equilibrium coefficient or to eliminate a parameter which is especially subject to experimental error.The analytically determined characteristic velocities are compared with pulse velocities obtained from numerical solution of the original balance equations. The agreement over a range of solute concentrations is excellent.
General mathematical model for mass transfer accompanied by chemical reaction
Authors: Huang Chen‐Jung , Kuo Chiang‐Hai 
Published: June 2004

AbstractThe present paper concerns the mechanism of mass transfer accompanied by a first‐order irreversible chemical reaction between two phases. Based on the film‐penetration concept a general mathematical model to describe the physico‐chemical behavior at the interface has been formulated. Mass transfer mechanism may be analyzed and evaluated in terms of the dimensionless groups appearing in the derived equations.For limiting conditions the derived general equations can be reduced to those based on the simple postulations such as the film theory, the penetration theory, and the surface renewal theory. For nonlimiting cases the film‐penetration concept provides information which cannot be obtained by either the film theory or the surface renewal theory alone.Experimental results appearing in literature show that the physical mass transfer coefficient is proportional to the molecular diffusivity to the v‐th power and that v varies widely between 0.15 and 1.0. The film‐penetration concept theoretically predicts this v‐variation, whereas, in accordance with the film theory or the surface renewal theory, v has to be a certain fixed value.It is shown that if an accurate physical mass transfer coefficient is available, the film‐penetration concept, the film theory, and the surface renewal theory all predict practically the same effect of chemical reaction on the mass transfer rate. However if the chemical mass transfer coefficient is to be predicted without an accurate physical transfer coefficient, the choice of the theory or the mechanism may become important.
Diffusivity of hydrogen in pure iron
Authors: Bryan W. L. , Dodge B. F. 
Published: June 2004

AbstractThe rate of permeation of hydrogen through a highly purified iron (Ferrovac E) was measured over a pressure range of 1/30 to 300 atm. and a temperature range of 126° to 693°C. The effect of cold working of the annealed metal and of hydrogen purity were also studied. Permeability, diffusivity, and solubility were obtained from the data. Permeation rate was linear with square root of fugacity rather than pressure. No difference in ϕ or D between the annealed and cold worked tube was observed. LogDvs. 1/Twas linear over the whole range of temperature, in disagreement with recent work showing a break in the plot at about 400°C. The calculated activation energy was lower than values reported in the literature. Solubility agreed well with most previous work and did not show the break in the solubility vs. temperature curve found by some recent investigators. No ageing effect was observed nor any difference between the two grades of hydrogen. All the evidence shows that diffusion through the metal is the controlling rate process in this case.