摘要:

AbstractThe Navier‐Stokes equations in stream‐function/vorticity form were solved numerically by over‐relaxation for the case of steady state, fully developed, isothermal, incompressible viscous Newtonian flow within a rigorously treated toroidal geometry. Solutions were obtained for curvature ratios ranging from 5 to 100 and for Dean numbers as low as I and as high as 1000. The Dean number was demonstrated to be the principal parameter to characterize toroidal flow; however, a second‐order dependence upon the curvature ratio above that expressed in the Dean number was observed. Comparisons of the numerically computed axial‐velocity profiles were made with experimental data. The cross‐sectional pressure distribution was calculated, and a correlation is presented for a diametral pressure drop in terms of the

ISSN:0001-1541    

DOI:10.1002/aic.690190113

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractAn analytical study was carried out on the effects of mixing on radiation‐induced polymerization in which the species initiating the polymerization were not uniformly produced because of a nonuniform dose rate distribution. The analysis is based on the periodic irradiation of fluid elements circulating in a stirred‐tank reactor having a high dose rate region and a very low dose rate region. It is shown that the rate of polymerization increases with agitation speed and that the bimodal molecular weight distribution of the polymer formed at low agitation speed moves to a unimodal distribution as the agitation speed increa

ISSN:0001-1541    

DOI:10.1002/aic.690190114

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe physical and mathematical characteristics of carrier‐facilitated transport in a liquid film are examined for a reaction scheme of the formA+B⇄AB, in whichAis the permeating species andBandABare diffusable species which are constrained not to leave the film. For thin films, a solution is developed as a perturbation from purely physical diffusion and is expressed as a second‐order power series. For thick films, a solution is developed as a perturbation from a state in which the species concentrations at any one point within the film are related by an equilibrium constraint. This development utilizes the techniques of matched asymptotic analysis. Taken together, these solutions provide an excellent estimate of the facilitation for a film of any thickness, as shown by comparison with numerical re

ISSN:0001-1541    

DOI:10.1002/aic.690190115

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractA geometric model for an homogeneous and isotropic porous medium composed of spherical particles is proposed. This model requires a minimum of geometric simplifications and lends itself to the study of hydrodynamic as well as diffusive flow processes, permitting in each application a mathematically rigorous and fully predictive analysis leading to mathematical representations of the respective flow parameters.This particular investigation seeks to evaluate, and to provide physical insight into, diffusive flow processes occurring within an homogeneous swarm of spherical particles.

ISSN:0001-1541    

DOI:10.1002/aic.690190116

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractA pure gold tube was found to give filmwise condensation in the absense of organic contamination in a flow sitution simulating that found in seawater conversion plants. A sensitive test for the presence of organic contamination has been developed. The gold tube, promoted by paraffinic thio‐silane or mercaptan, gave 100% excellent dropwise condensation. Overall heat transfer coefficients are reported for filmwise and dropwise condensation. The steamside heat transfer coefficient with dropwise condensation was estimated to be over 0.2 MW/m2‐°C (35,000 B.t.u./hr‐ft2‐°F) at the 95% confidence level.Gold plated tubesSupplied by P. Tomalin and S. Mulford of the Office of Saline Water, USDI.gave 95% filmwise condensation after one week of operation in a clean, once‐thr

ISSN:0001-1541    

DOI:10.1002/aic.690190117

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractA new method for suboptimal feedback control of certain classes of distributed systems based on successive instantaneous minimization of the performance functional kernel is presented. This method is applicable to both linear and nonlinear systems.The Lyapunov functional approach is extended to distributed systems, yielding two new suboptimal feedback control techniques. Also, an application of multilevel bang‐bang control to the first‐order hyperbolic system is presented and generalized.Advantages and disadvantage ofthe suboptimal control techniques vis á vis open loop optimal control methods are listed, as well as comparative features of the suboptimal control met

ISSN:0001-1541    

DOI:10.1002/aic.690190118

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe suboptimal control algorithms developed in Part I are tested on four example problems to obtain some indication of their performance. Results are presented and compared with results obtained from the application of classical open‐loop optimal control synthesis algorithms to the same test problems.The suboptimal feedback control algorithms are found to give acceptable performance on both linear and nonlinear systems at the expense of very little computational effor

ISSN:0001-1541    

DOI:10.1002/aic.690190119

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractHydrogen, a quantum gas, raises to unique problemsin the estimation of liquid properties of mixtures containing dissolved hydrogen–a problem often encountered in hydroprocessing of hydrocarbons. The liquid density and enthalpy of a hydrogen‐containing mixture in particular are not adequately described by the pseudocritical concept but are best calculated by summing the liquid partial molar quantities of hydrogen and that of hydrogen‐free liquid solvent.Liquid partial molar volumes and enthalpies of hydrogen have been evaluated and the results, including the effects of pressure and composition, presented in generalized equations. These generalized equations are shown to be useful in estimating the liquid density and enthalpy of hydrogen containing mix

ISSN:0001-1541    

DOI:10.1002/aic.690190120

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractLiquid‐vapor phase equilibria measurements were made at 112.00 K on the binary systems nitrogen‐argon, nitrogen‐methane, and argon‐methane and the ternary system nitrogen‐argon‐methane. Values of gE, the excess Gibbs free energy, have been calculated from the experimental data for all the systems studied. The data and derived gEvalues for the binary systems were compared with the results of previous investigations with satisfactor

ISSN:0001-1541    

DOI:10.1002/aic.690190121

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractAn approximate analysis is given for miscible displacement in vertical tubes when density differences between the displaced and displacing fluids give rise to buoyancy forces which affect the velocity distribution significantly. The results of this analysis agree with the available experimental data fairly uniformly over the range of parameters studied experimentally.By analogy with studies of heat transfer in vertcal tubes it is concluded that both cases studied, when a lighter fluid displaces a heavier fluid in upflow, or when the heavier fluid is below the lighter fluid, are potentially unstable flows because buoyancy forces can create points of inflection in the velocity profile; stagnation at the wall also is predicted for upflow when the lighter fluid is on the bottom initially, and this has been observed to induce a sudden transition to turbulence in heat transfer systems.Buoyancy forces reduce the extent of dispersion by flattening the velocity profile when the heavier fluid is on the bottom in upflow. The velocity profile is elongated and the dispersion coefficient is increased when the bottom fluid is lighter than the one it displaces in upflow.

ISSN:0001-1541    

DOI:10.1002/aic.690190122

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY