摘要:

AbstractThis paper presents a nonequilibrium mathematical model of a vapor‐liquid separator. The model is used as the focus of a computer simulation control study conducted to provide the foundation for applying recent multivariate control developments to distillation systems.Greenfield and Ward's structural analysis was found to provide reasonably good feedforward and decoupling control of pressure, liquid temperature, and liquid pressure. Because of implicit relationships between product composition variables and their manipulative inputs, structural analysis was inapplicable when these composition variables were among the controlled variables.A method is presented which provides feedforward and some decoupling control for linear multivariable systems despite the existence of implicit relationships between controlled variables and their manipulative inputs. It is seen however that genuinely decoupled servo action on isolated state variables requires control through derivatives and thus an expansion of state spac

ISSN:0001-1541    

DOI:10.1002/aic.690170308

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractMean velocity and turbulence measurements in the void spaces of a cubic packing of equal spheres have been made at Reynolds numbers of 27,000, 10,000, 5,000 and 2,500, whereNReis based on superficial air velocity and a sphere diameter of 7 cm. Two cubic arrangements were used: in the regular arrangement, the mean flow was parallel to one of the principal axes, while in the skewed arrangement, the mean flow made equal angles with the three principal axes of the packing.Transverse mean velocity and turbulence intensity profiles across the center line of a central pore have been measured behind every bank and behind the bed for the regular arrangement of ten banks of spheres. The power spectrum and probability distribution of the fluctuating velocity have also been determined.

ISSN:0001-1541    

DOI:10.1002/aic.690170309

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractA mathematical model of the heavy water production facility at the Savannah River Plant, an installation of the U.S. Atomic Energy Commission at Aiken, South Carolina, operated by E. I. du Pont de Nemours and Company, was developed because measured production rates, even when averaged over one‐month periods, are inadequately precise for process control. With this model the instantaneous steady state production rate for any set of process conditions is calculated with precision. Therefore the model is used to establish process set points for achieving production goals, to study the effect of important process variables on these goals, and to evaluate proposed changes of equipment. In fact, with only minor changes in the computer program, several features of a newly designed heavy water plant are being evaluate

ISSN:0001-1541    

DOI:10.1002/aic.690170310

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractThe processes of absorption and desorption with reversible reaction are compared theoretically for reactions of the typeA⇌nB. With the same concentration difference between bulk and interface, it is found that in general, the rate of desorption is lower than that of absorption. Under certain conditions the difference may be as much as 35%.The analysis is based on the penetration theory. The numerical solution introduces a new transformation of the time and distance variables (based on the error function) which reduces the computing time required. An analytical examination of the penetration theory equations provides an explanation of the results of the numerical solutio

ISSN:0001-1541    

DOI:10.1002/aic.690170311

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractThe rates of hemoglobin saturation and carbon dioxide reduction in blood flowing in a curved channel membrane exchanger were studied theoretically by considering the fluid‐limited process and the wall‐limited process. The fluid‐limited process was studied for laminar flows with and without secondary circulations. The relatively nontraumatic centrifugally induced circulations in the curved channel can reduce the required channel length to less than 1/500 that required for unperturbed flow. Such improvement, however, is practical only if very permeable membranes are available. If thePO2= 715 mm. Hg andPCO2= 0 mm. Hg at the walls, the fluid‐limited analyses show oxygenation to be the slower process and the wall‐limited analyses indicate CO2removal to be the limiting process. If the best available silicone rubber membranes are used, the process will be fluid limited for the unperturbed flow and wall limited for the flow with secondary cir

ISSN:0001-1541    

DOI:10.1002/aic.690170312

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractThe relaxed steady state operation of a tubular fixed‐bed catalytic reactor under control of the inlet composition is investigated. It is shown that the performance of such a reactor can be improved under certain conditions by periodically varying inlet concentrations rather than keeping these concentrations time invarian

ISSN:0001-1541    

DOI:10.1002/aic.690170313

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractA theoretical model is derived which permits the analytical calculation of the friction factor‐Reynolds number curves for non‐Newtonian slurries flowing isothermally in smooth pipes. This model is based upon the Bingham plastic rheological equation of state.A change of mechanism in the transition phenomenon is observed to occur forNHe= 5 (105), whereNHeis the familiar Hedstrom number. Below this value turbulence is suppressed relative to Newtonian flow, while above this value the transition is delayed but turbulence is enhanced relative to Newtonian flow.A set of theoretical design curves of friction factor versus Reynolds number covering laminar, transitional, and turbulent flows is calculated and presented for a range ofNHevalues from 103to

ISSN:0001-1541    

DOI:10.1002/aic.690170314

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractIn this paper we consider the problem of the flow of a viscous incompressible fluid down an inclined wall. A solution is obtained by assuming that the free surface is a wave of low frequency. The solution is numerical and the results are compared with existing theories and available experimental results.

ISSN:0001-1541    

DOI:10.1002/aic.690170315

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractAn analytical technique based on the method of least squares has been developed to fit experimental second virial coefficients to the functional form derived from the Lennard‐Jones (6–12) potential. Both the functional form and the normal equations of the least squares fit are rigorously derived. Because of the implicit, nonlinear dependence upon one of the adjustable parameters, a computer solution of the normal equations is required. Second virial coefficient data for a large number (60) of materials, including hydrocarbons, halides, alcohols, and cyclic compounds, have been extracted from published sources, carefully evaluated for consistency, and fitted to the Lennard‐Jones potential function.Force constants for these materials as determined from fitting the data in this uniform manner have been found to be related to structural parameters. The final correlation, with the potential well‐depth related to critical temperature and the collision diameter calculated from a set of group contributions with appropriate corrections for polarity and/or association, produces average deviations between computed and experimental second virial coefficients of 10 to 15% or 100 cc./g.‐mole, whichever is greater. In many cases the agreement is mu

ISSN:0001-1541    

DOI:10.1002/aic.690170316

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY

摘要:

AbstractEffective experimental and theoretical techniques for studying the heat transfer characteristics of a stationary evaporating meniscus formed on a flat plate immersed in a pool of liquid were developed. Integral heat transfer data were obtained for the four systems: 304 stainless steel‐water, 6061 aluminum‐water, 304 stainless steel‐methanol, and 6061 aluminum‐methanol. High rates of heat transfer were obtained in the triple interline region with a stable meniscus. Detailed descriptions of the heat flux and temperature field were obtained for the stainless steel‐water and stainless steel‐methanol systems. The effect of the evaporation coefficient on the heat flux distribution was evaluated. The heat transfer process in the interline region proved to be more efficient than a simple conduction process in an evaporating liqu

ISSN:0001-1541    

DOI:10.1002/aic.690170317

出版商:American Institute of Chemical Engineers    

年代:1971

数据来源: WILEY