bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inception criteria for droplet entrainment in two‐phase concurrent film flow
Authors: Ishii M. , Grolmes M. A. 
Published: June 2004

AbstractInception criteria for droplet entrainment in concurrent gas‐liquid film flow were developed from simple physical models. For film Reynolds number ≳ 160, an entrainment model based on the shearing off of roll‐wave crests was used. At lower film Reynolds numbers, a wave undercutting mechanism was introduced. Experimentally observed abrupt changes in the critical gas velocity corresponding to the onset of entrainment at a certain film Reynolds number have been explained by the shift in the entrainment mechanisms. An agreement of the present inception criteria with various experimental data is shown to be satisfactory, and significant improvements over the existing empirical correlations have been made.
Freeze dehydration by microwave energy: Part II. Experimental study
Authors: Ma Yi Hua , Peltre Philippe R. 
Published: June 2004

AbstractExperimental drying curves have been obtained for the freeze‐dehydration of beef meat with microwave energy at 2450 MHz. In particular, experiments conducted with slabs of raw beef meat approximately 1.5 cm thick show that total drying times of less than 6 hr. can be obtained. Further drying time reductions are possible if microwave heating and freezing techniques are improved. Samples can be dried slightly faster at a higher pressure (for example, 1 mmHg) than at a lower pressure (for example, 0.2 mmHg) for the same microwave power input. However, melt back and vaporization occur if the pressure or the microwave power input is too high.Comparison of the experimental drying curves with those predicted by the theory shows a reasonable agreement which, at least in part, verifies the validity of the previously derived mathematical model.
A generalized thermodynamic correlation based on three‐parameter corresponding states
Authors: Lee Byung Ik , Kesler Michael G. 
Published: June 2004

AbstractThe volumetric and thermodynamic functions correlated by Pitzer and co‐workers analytically represented with improved accuracy by a modified BWR equation of state. The representation provides a smooth transition between the original tables of Pitzer et al. and more recent extensions to lower temperatures. It is in a form particularly convenient for computer use.
Convergence promotion in the simulation of chemical processes—the general dominant eigenvalue method
Authors: Crowe C. M. , Nishio M. 
Published: June 2004

AbstractThe objective of this study was to devise an improved method of accelerating the iterative computation of steady state simulations of chemical processes. An extension of the dominant eigenvalue method is presented and its effectiveness is tested with simulations of chemical processes. The method is compared to previously available methods and is found to achieve convergence more rapidly and indeed was effective in cases where some other methods were ineffective or did not take a promotion step at all. The proposed method is applicable to the acceleration of any iterative computation of a nonlinear fixed‐point problem.
The behavior of a power‐law fluid flowing through a sudden expansion: Part I. A numerical solution
Authors: Halmos A. L. , Boger D. V. , Cabelli A. 
Published: June 2004

AbstractA numerical solution for the axisymmetric flow of an inelastic power‐law fluid through an abrupt circular expansion is presented. The equations of motion were solved using an Alternating Direction Implicit method. Both a stream tube‐real tube and a real tube‐real tube model were investigated and the conditions for significant upstream diffusion of momentum were specified. Secondary flow characteristics and the bulk flow field development are predicted as a function of the flow behavior index (n) and of the Reynolds number. Some results are presented to show the influence of the expansion ratio.
Transport of mass in ternary liquid‐liquid systems. Part I. Diffusion studies
Authors: Sethy Anil , Cullinan Harry T. 
Published: June 2004

AbstractThe diffusional behavior of the ternary partially miscible liquid system acetonitrile‐benzene‐n‐heptane is investigated at 25°C using the diaphragm cell technique. The mutual diffusivity of the partially miscible binary system acetonitrile‐n‐heptane is found to be a strong function of concentration; the concentration dependence is described using a linear relationship. The diffusion coefficient matrix of the ternary system acetonitrile‐benzene‐n‐heptane is determined at a number of points, and the ternary diffusion matrices are found to be significantly coupled with the off‐diagonal elements of about 10 to 40% of the main diffusion coefficients.
Statistical characteristics of thin, wavy films III. Structure of the large waves and their resistance to gas flow
Authors: Chu K. J. , Dukler A. E. 
Published: June 2004

AbstractTwo classes of random waves exist on falling films at flow rates of practical interest; large waves which carry the bulk of the liquid and small waves which cover the substrate. In this paper statistics of the large waves are presented and compared with existing theory. These waves are bimodal in character at ReL > 700. The form drag of the large waves is shown to contribute negligibly the observed pressure drop in the gas phase. It is thus concluded that the small wave structure controls the fluid resistance and transfer processes in the gas while the large waves control these same processes in the liquid film.
Grouping of many species each consumed by two parallel first‐order reactions
Authors: Luss Dan , Golikeri Sudhir V. 
Published: June 2004

AbstractThe behavioral features of a mixture containing many species each of which participates in two competing parallel first‐order reactions may deviate significantly from those of the individual species. For example, the grouped selectivity may depend on the conversion and attain up to N‐2 extremal values where N is the number of the reactants in the mixture. The kinetics of the grouped species depends on the composition of the feed and can be of an unconventional functional form. The use of empirical grouped kinetics may lead to unexpected pitfalls. For example, grouped rate expressions based on experiments carried out in one reactor may not be adequate for predicting the behavior in a reactor with a different residence time distribution.
Synthesis of separation sequences by ordered branch search
Authors: Rodrigo B. Fernando R. , Seader J. D. 
Published: June 2004

AbstractAn efficient and algorithmic procedure is developed for the synthesis of multicomponent separation sequences. The procedure involves list processing of the prossible separation subproblems followed by an ordered branch search to find the optimal sequence with respect to system structure. The technique is conveniently represented by an and/or directed graph. The distribution of sequence costs for a separation problem is considered. When a wide distribution exists, only a minimum of separators need be analyzed to find the optimal sequence. Even when a narrow distribution of sequence costs exists, not all sequences must be developed. The importance of near optimal sequences is examined, and the search procedure is extended to find those sequences whose costs are within a specified factor of the cost of the optimal sequence.
Mixing in the interaction zone of two free jets
Authors: Becker H. A. , Booth B. D. 
Published: June 2004

AbstractMixing in the interaction zone of two round free jets with nozzle axes intersecting at half‐angles of 15, 30, and 45 deg. has been studied by the smoke scattered light technique. The fields of mean concentration and concentration fluctuation intensity were mapped with one jet marked with smoke, the other jet marked, and both jets marked. The correlation function between the concentration fluctuations associated with fluid of the two nozzle streams has been calculated from the results and is an important characteristic of the mixing field and a significant measure of molecular mixedness. A transport equation for the associated covariance function is derived, and the special features of the mathematical modeling problem for this class of mixing process are discussed. The implications of the results for processes involving chemical reactions are examined.
Numerical treatment of laminar flow in helically coiled tubes of square cross section. Part II. Oscillating helically coiled tubes
Authors: Joseph B. , Adler R. J. 
Published: June 2004

AbstractThe numerical method of Part I is extended to study periodic laminar flow in helically coiled tubes of square cross section oscillating sinusoidally about their helix axis. Depending on the relative strength of the wall velocity and the velocity of flow through the tube, one of three flow regimes occur. When the wall velocity is small, the computed results resemble these for a stationary helix. When the wall velocity dominates, the direction of the secondary flow is reversed. When the wall and flow velocities are comparable, the secondary flow pattern varies periodically in time and sometimes alternates in direction.
Breakup of a turbulent liquid jet in a low‐pressure atmosphere
Authors: Phinney Ralph E. 
Published: June 2004

AbstractBreakup length measurements were made of turbulent liquid jets in a low‐pressure atmosphere. As a result of these experiments, it was found that the jets obey a pseudo laminar analogy only at low exit velocity. The nondimensional breakup length correlates with the jet Weber number through the complete range.
Transient viscoelastic flow of polymer solutions
Authors: Leppard W. R. , Christiansen E. B. 
Published: June 2004

AbstractStress growth and stress decay data for two highly viscoelastic polymer solutions indicate that the first and second normal stress differences grow and decay at the same relative rates. These shear stress and first normal stress difference data are not represented well by the Spriggs, Bogue‐Chen, or Carreau constitutive equations. The second normal stress difference, stress growth, and decay data are the first to be reported. The data were derived from radial pressure distributions and total normal and tortional forces obtained in cone and plate shearing. Sensitive miniature pressure transducers with pressure sensing diaphragms mounted flush with the plate surface provided the radial pressure distribution data.
The vapor‐liquid equilibrium of the hydrogen—n‐butane system at elevated pressures
Authors: Klink A. E. , Cheh H. Y. , Amick E. H. 
Published: June 2004

AbstractThe vapor‐liquid equilibrium of the hydrogen–n–butane system was studied at temperatures between 54° and 121°C and at pressures up to 167 atm. The fugacity of hydrogen in the vapor phase was measured directly by using a palladium‐silver semipermeable membrane, whereas p‐T‐x‐y data were obtained in a conventional manner.Henry's constants for hydrogen in n‐butane were obtained from the experimental fugacity data without making any assumptions about the vapor phase. Constant‐pressure, liquid‐phase activity coefficients for both hydrogen and n‐butane were calculated and correlated by using a modified van Laar equation.
On the prediction of ultimate separation in parametric pumps
Authors: Foo S. C. , Rice R. G. 
Published: June 2004

AbstractQuantitative theories based on first principles are derived to explain the roles of heat and mass transfer in the attainment of steady state or ultimate separation in closed direct‐thermal‐mode parametric pumps. The theoretical results are in agreement with applicable experimental data, including the experimental anomaly called reversed separation. Under conditions when the axial dispersion is much greater than molecular diffusion, the theory predicts and experiments confirm that 1/ln(α∞) varies in a linear way with fluid displacement at constant frequency. An additional asymptotic result suggests that when Sh » PeM, there is a simple linear connection between 1/ln(α∞) and PeM which is supported by experimental data.
Turbulent motion, mixing, and kinetics in a chemical reactor configuration
Authors: McKelvey Kenneth N. , Yieh Heh‐Nien , Zakanycz Stephen , Brodkey Robert S. 
Published: June 2004

AbstractThe nature of turbulence and mixing in a reactor used by Toor for kinetic studies was investigated in detail. Simple empirical methods were useful for estimating the decay of the scalar fluctuations. An equation, based on continuity, was used with measured velocities and an improved procedure at the inlet to calculate results that agree well with the kinetic data.
An unsteady state method for measuring the permeability of small tubular membranes
Authors: Stevenson James F. , Von Deak Michael A. , Weinberg Mark , Wade Schuette R. 
Published: June 2004

AbstractAn experimental method is described for measuring the permeability of small tubular (hollow fiber) membranes by means of an unsteady state diffusion experiment. Permeability data obtained by this method are reported for experimental collagen and commercial cellulose acetate membranes for urea, sucrose, and polyethylene glycol (MW ∼ 4 000).
The stability of a vertical flow which arises from combined buoyancy modes
Authors: Boura Andre , Gebhart Benjamin 
Published: June 2004

AbstractWe consider a mass transfer induced buoyancy force, superimposed on a thermally induced one, in a flow generated adjacent to a vertical surface. Flow and stability were investigated for a Prandtl number of 0.7; for Schmidt numbers of 2.0, 0.94, and 0.2; and for different magnitudes of the buoyancy effects.
Secondary nucleation of two fast growth systems in a mixed suspension crystallizer: Magnesium sulfate and citric acid water systems
Authors: Sikdar Subhas K. , Randolph Alan D. 
Published: June 2004

AbstractSecondary nucleation of magnesium sulfate and citric acid was studied in a seeded back mixed crystallizer. The MSMPR type of exponential population density distribution was obtained above 8 μm size in quasi steady state operation. Growth rates were satisfactorily correlated with supersaturation. Nucleation rates correlated with supersaturation and slurry properties. Agitation level (RPM) did not have any significant effect on the nucleation rates, presumably implying surface regeneration limited nucleation.
Experimental study of the residence time distribution in plasticating screw extruders
Authors: Wolf David , White Don H. 
Published: June 2004

AbstractExperimental residence time distribution functions for the liquid and solids conveying processes by a screw conveyer and for the polymer in a plasticating extruder were obtained by using a radioactive tracer technique. A comparison was made between the experimental results and several theoretical models available for melt extrusion and mixing processes.
Transient diffusion in solids with a bipore distribution
Authors: Ma Y. H. , Lee T. Y. 
Published: June 2004

AbstractTransient diffusion of n‐butane, iso‐butane, and 1‐butene in synthetic CaX(Na) spherical pellets is studied in a constant volume, well‐stirred system. The intracrystalline diffusion coefficients are in the order of 10−14 cm2/s, and the activation energy is about 7.0 Kcal/g‐mole. Experimental data agree well with a mathematical model developed to describe transient diffusion.
Prediction of transport processes within porous media: Diffusive transport processes within anisotropic or isotropic swarms of nonspherical particles
Authors: Neale G. , Nader W. K. 
Published: June 2004

AbstractThe effects of particle shape and orientation upon diffusive transport processes occurring within unconsolidated porous media are investigated analytically. By means of a generalization of an earlier presented geometric model, diffusivities are predicted for both anisotropic systems (represented by swarms of aligned oblate or prolate spheroids) and isotropic systems (represented by swarms of randomly orientated spheroids). Theoretical predictions are compared with experimental data reported in the literature.
Adsorption and desorption of particles and their chromatographic separation
Authors: Ruckenstein Eli , Prieve Dennis C. 
Published: June 2004

AbstractRates of adsorption/desorption are calculated by considering Born, double‐layer, and van der Waals forces. Conditions exist where rates are highly sensitive to particle size, shape, and chemical constitution because diffusion over a potential barrier controls. On this basis, a new separation technique, called potential‐barrier chromatography, is suggested.
Steady state multiplicity of adiabatic gas‐liquid reactors: II. The two consecutive reactions case
Authors: Sharma Shanmuk , Hoffman Lee A. , Luss Dan 
Published: June 2004

AbstractA model describing two consecutive gas‐liquid reactors in a continously stirred‐tank reactor is developed with reaction factors used to account for the interactions between the chemical and transport rate processes. A parametric numerical study revealed several interesting effects, including the existence of up to seven steady state solutions. The predictions of the model adequately describe the steady state multiplicity observed during the chlorination of liquid n‐decane. It is shown that the steady state multiplicity can serve as an excellent tool for discriminating among rival models and estimation of kinetic parameters.
Axial distribution of reactivity inside a fluid‐bed contactor
Authors: Furusaki Shintaro , Kikuchi Tatsuji , Miyauchi Terukatsu 
Published: June 2004

AbstractThe axial destribution of reactivity inside a fluid‐bed contactor is studied for the hydrogenation of ethylene. The reactivity is large near the surface of the dense phase. The significant effect of the dilute phase, or the free board region, is verified experimentally, and the contact efficiency in the transition zone and in the dilute phase is obtained. The contact efficiency was approximated by ηc = 1 − 0.75 (ϵe/ϵede)0.4. The temperature rise in the dilute phase is measured in the small reactor. The transition zone between the dense and dilute phases is almost isothermal, but it is found that temperature increases in the dilute phase.
The rheological properties of suspensions of rigid particles
Authors: Jeffrey D. J. , Acrivos Andreas 
Published: June 2004

AbstractExperimental and theoretical work on the rheological properties of suspensions are reviewed. Attention is focused on systems consisting of rigid, neutrally buyoant particles suspended in Newtonian fluids; no restrictions, however, are placed on the concentration of the particles or on the forces acting in the suspension. The assumption that an effective viscosity depending solely on the volume fraction of the particles suffices to describe the rheology of suspensions is examined and shown to be inadequate. Indeed, the experimental evidence strongly supports the view that suspensions behave macroscopically as non‐Newtonian fluids whose rheological properties are influenced by a large number of factors; these factors are listed. The various theories that have been put forward to explain the flow of suspensions are discussed, with particular emphasis being placed on the nature of the approximations made, so that purely empirical formulas can be clearly separated from those having a theoretical basis. Suggestions for future work, both theoretical and experimental, are provided.
Onset of draw resonance during isothermal melt spinning: A comparison between measurements and predictions
Authors: Weinberger C. B. , Cruz‐saenz G. F. , Donnelly G. J. 
Published: June 2004

AbstractVarious polymer melts were spun isothermally to determine the critical extensional strain at which draw resonance occurs. Simultaneously, the variation of apparent spinning viscosity with extensional strain was measured. Experimental results failed to confirm the theoretical prediction that strain thickening behavior leads to enhanced stability.
Lagrangian simulation of dispersion in turbulent shear flow with a hybrid computer
Authors: Lee Naugab , Dukler A. E. 
Published: June 2004

AbstractTwo‐dimensional turbulent diffusion is modeled with a generalized Langevin equation. Instantaneous velocities are simulated by using white noise filtered to simulate turbulence. By generating fluctuating signals that are partially correlated, it is possible to model diffusion for a turbulent shear field. The result show that the dispersion is independent of shear for long and short diffusion times but depend strongly on shear for intermediate times.
Optimal design of pressure relieving piping networks by discrete merging
Authors: Cheng Wai‐biu , Mah Richard S. H. 
Published: June 2004

AbstractRefinery relief‐header network design can be optimized by a new discrete optimization technique which requires no rounding of decision variables, no initial guesses for the solution, and no artificial termination criteria; it produces parametric solutions when the optimum is attained. The method is also faster and more compact than the alternative continuous optimization methods.
An effective computational algorithm for suboptimal singular and/or bang‐bang control II. Applications to nonlinear lumped and distributed systems
Authors: Nishida N. , Liu Y. A. , Lapidus Leon , Hiratsuka S. 
Published: June 2004

AbstractA new and simple algorithm based on the piecewise maximization of the Hamiltonian and a limiting process utilizing a penalty function of the control variables for the computation of suboptimal singular and/or bang‐bang control, previously developed and applied to linear lumped systems in Part I, is tested on four typical nonlinear lumped and distributed systems of particular chemical engineering interest. The computational results have shown that the proposed algorithm is a very effective method for solving singular and/or bang‐bang control problems with high state dimensionality, extreme nonlinearity, and multiple controls.
Trajectory analysis of deep‐bed filtration with the sphere‐in‐cell porous media model
Authors: Rajagopalan Rajamani , Tien Chi 
Published: June 2004

AbstractThis paper presents a model for the initial particle deposition in a deepbed filter with a sphere‐in‐cell porous media model used. The analysis includes all the relevant mechanisms, and the results indicate that deposition occurs under favorable surface interactions. A semiempirical expression relating collection efficiency and operating parameters is presented.
Solution procedures for indexed equation sets: Structural considerations
Authors: Allen Gary L. , Westerberg Arthur W. 
Published: June 2004

AbstractResults are obtained permitting the systematic development of solution procedures for indexed equations by analyzing and combining a number of small problems. The solution procedures obtained are independent of index limits and can be written compactly by using nested FORTRAN DO‐loops or equivalent. To illustrate the approach, a solution procedure is developed for a multistage, multicomponent distillation column segment. The solution procedure is valid for any number of stages and components.
Capture of small paramagnetic particles by magnetic forces from low speed fluid flows
Authors: Cummings Daniel L. , Himmelblau David A. , Oberteuffer John A. , Powers Gary J. 
Published: June 2004

AbstractHigh gradient magnetic separators are able to capture small, dilute, paramagnetic particles from high velocity fluid flows. Capture cross sections are computed and correlated with dimensionless groups for a bare ferromagnetic collector.
The fluid mechanics and heat transfer of injection mold filling of thermoplastic materials
Authors: Kuo Youti , Kamal Musa R. 
Published: June 2004

AbstractFor injection flow of thermoplastic material in thin cavities, with some minor restrictions, both pressure and stream function obey Laplace equations. An analytical‐numerical method, with a generalized viscous model used, is developed for determining the shape of a progressing flow front and for computing flow quantities and temperature distributions. Specifically, flows in a rectangular cavity are solved and compared to experiments.