摘要:

AbstractNo Abstracts.

ISSN:0001-1541    

DOI:10.1002/aic.690150602

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractAn earlier study on interphase mass transfer in pulsating laminar flow has been extended to the case of a distensible tube. The physical situation studied corresponds to developed flow in a long tube with a traveling pressure wave of small amplitude impressed on the steady flow. The tube wall is free to expand radially. Asymptotic solutions are developed for large and small values of the frequency parameter. The interphase flux is much greater in distensible conduits than in the corresponding case in rigid conduits.

ISSN:0001-1541    

DOI:10.1002/aic.690150604

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractAn experimental and analytical study was made to determine how well the material functions, derived from the Spriggs four‐constant viscoelastic model, could describe the rheological properties of polymer melts. Viscosity and elasticity of selected polymer melts were experimentally determined in the rotational and oscillatory modes using a Weissenberg Rheogoniometer. The Spriggs model was chosen for study because of its success in describing experimental data for polymer solutions and because of its uniqueness in combining results from molecular theory with results from the theories associated with continuum mechanics. It was found that the model provides a good description of the rheological data for polymer melts and that some of the model parameters depend upon the molecular characteristics of the polymer. Since this model contains a small number of well defined constants, it should be useful in developing dimensionless engineering correlations for the complex flows encountered in processes of industrial importance. Deviations between the theoretical and experimental results are discussed and deficiencies of the model note

ISSN:0001-1541    

DOI:10.1002/aic.690150605

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractEquations were developed for evaluating the laminar flow behavior of high‐solids suspensions from the physical properties of the liquid and solid components. A technique was developed for calculating suspension flow rates as a function of pressure drop. The technique is applicable to the design of pipe lines. Flow measurements were made in pipe‐line viscometers of a unique design that minimized entrance and exit effects. Experimental flow data were obtained for suspensions consisting of nickel, alumina, copper, or glass solids in sodium, xylene, or glycerine vehicles with solids concentrations of 28 to 55 vol. %. The basis for the correlation of the data was an analytical investigation of the flow behavior that considered the particle‐particle interaction that takes place in a settled suspension. The correlation equations fit all systems investigated. They take into account the effects of liquid viscosity, liquid and solid densities, particle size, size distribution, particle surface area, volume fraction of solids in the suspension, and volume fraction of solids at maximum settled condi

ISSN:0001-1541    

DOI:10.1002/aic.690150606

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA general numerical‐analysis procedure is presented for the screw extrusion of a non‐Newtonian material. The full Navier‐Stokes energy and continuity equations are used in the numerical procedure. The flow is taken as steady and incompressible, and the viscosity is written according to the Ostwald‐de Waele model in which the viscosity is assumed to be inversely proportional to the square root of the second invariant of the rate of deformation tensor and exponentially dependent on the temperature.The procedure allows the prediction of vorticity, stream‐function, swirl velocity, internal energy, and viscosity over any cross section of a groove containing plastic. Calculations for the mass extrusion rate and power consumption (shear rate) for the screw extruder are also given. Typical cases are considered for which all the quantities listed above are determined. The results compare favorably with other theoret

ISSN:0001-1541    

DOI:10.1002/aic.690150607

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA generalized approach to reverse osmosis process design is presented for solution‐membrane‐operating systems characterized by the dimensionless parameters γ, θ, and λ defined in terms of the pure water permeability constant A, solute transport parameter (DAM/Kδ), mass transfer coefficientkon the high pressure side of the membrane, and the properties of the solution. Analytical expressions are derived, in terms of dimensionless quantities, for the change of volume of solution, concentration of the bulk solution and that of the concentrated boundary solution on the high pressure side of the membrane, the change in the permeating velocity of solvent water through the membrane, solute separation, and the other related quantities, at any instance, as a function of concentration of the product solution on the atmospheric pressure side of the membrane, or time from the start of the operation for reverse osmosis systems specified by γ, θ, and λ. The equations are applicable to membranes for which (DAM/Kδ) is independent of solute concentration and feed flow rate, and for aqueous feed solutions whose molar density can be assumed constant and whose osmatic pressure is proportional to mole fraction. The equations are developed first for the case of batch‐by‐batch operation, and their applicability to the flow case is

ISSN:0001-1541    

DOI:10.1002/aic.690150608

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe phenomenon of reversing axial flow in swirling incompressible flow through a tube has been investigated experimentally. The study was carried out in a 2 in. I.D. test section of plexiglass tubing 10 ft. long. The swirl was introduced by injection of the total fluid stream through two symmetric tangential inlets perpendicular to the tube. Measurements have been made with specially constructed stagnation and static pressure probes.Velocity and pressure profiles obtained for tests conducted at four Reynold's Numbers in one fixed geometrical configuration are presented and discussed in general terms. Swirl decay rate is characterized in a plot of weighted tangential velocity/inlet velocity ratio versus distance along the test section from the inlets. A model presented by a previous investigator to explain the flow reversal phenomenon is discussed in the light of present work. Finally the data is used in an order of magnitude analysis to reduce the turbulent Navier‐Stokes equation describing the flow to simpler (though still indeterminate) for

ISSN:0001-1541    

DOI:10.1002/aic.690150609

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA method is derived for the design of stirred tank reactors for homogeneous reactions. A simple mixing model proposed previously by Curl (4) is used to compute the effects of finite mixing time on complex chemical reactions. It is also shown how the parameters of the model can be obtained by tracer experiments, or estimated theoretically by the assumption of isotropic turbulence. It is shown that in many practical cases the assumption of ideal mixing is a good approximation. However, the effects of imperfect mixing are more likely to be felt in a large reactor than in a pilot plant. Some quantitative examples are discussed. Methods are derived to compute the average outlet concentration for complex systems such as autothermic reactions, polymerization, crystallization, etc.

ISSN:0001-1541    

DOI:10.1002/aic.690150610

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA realistic CSTR model was developed and verified experimentally. The reaction studied was the exothermic, base sodium hydroxide catalyzed decomposition of hydrogen peroxide. The model was used to evaluate the usefulness of the following stability analyses: steady state analysis, local linearization and Liapunov's direct method through Krasovskii's theorem. The effect of control valve hysteresis on the system was also investigated.

ISSN:0001-1541    

DOI:10.1002/aic.690150611

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe final stages of condensation polymerization are characterized by a rapid rise in molecular weight, as the condensation product is formed and diffuses out of the polymer. The process occurring is one of desorption accompanied by a chemical reaction. The penetration theory equations for a generalized condensation polymerization reaction have been solved and some solutions are presented. The penetration theory solution, obtained by finite‐difference computations, is compared with an analytical solution for the special case of no diffusional resistanc

ISSN:0001-1541    

DOI:10.1002/aic.690150612

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY