ISSN:0001-1541    

DOI:10.1002/aic.690160304

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractThe present state of the theory of nonisothermal tube flow is inadequate to predict the behavior of polymer melts. In addition, relatively few experimental measurements on radial temperature profiles of polymer melts in the tube flow have been reported. For non‐Newtonian systems, the separation of viscous losses due to frictional heat generation and those due to the effect of shear rate is a formidable problem which has hampered progress. This paper will describe a method of measuring shear induced heating and present experimental data on radial temperature profiles in tube flow. A novel method of estimating the velocity profile is also describe

ISSN:0001-1541    

DOI:10.1002/aic.690160305

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractIn the context of a previously proposed new description for multiphase flow through porous media, we examine constitutive equations forgi, the force per unit volume which phaseiexerts upon the pore walls and other adjacent fluids. The principle of material difference is used to determine the most general dependence ofgiupon saturation gradient for a nonoriented (no porosity gradient) permeable structure.Three problems are solved and the results compared with analyses based upon our interpretation of Muskat's equations. The first concerns a semi‐infinite porous column in air, the bottom of which is saturated with a liquid. The same saturation distribution is found with our approach as with Muskat's equations.The analysis of the second problem indicates the relation between our relative permeability and that of Muskat.The jump balances for mass and for momentum at a surface of discontinuity (or shock wave) with respect to volume averaged variables are derived. The significance of solutions in which such surfaces of discontinuity appear is discussed.In the third problem, a plane surface of discontinuity with respect to local saturation moves through an infinite permeable structure. This is similar to the displacement of oil by an aqueous solution in a secondary recovery process. The results are comparable to those with Muskat's equations only in the limit where capillary pressure is neglected (the Buckley‐Leverett case). When capillary pressure differs from zero, Muskat's equations do not admit a shock wave solut

ISSN:0001-1541    

DOI:10.1002/aic.690160306

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractThe permeation of polyethylene film by carbon dioxide, ethane, and propane at elevated pressures was investigated. In addition, the separation of mixtues of ethane and propane by permeation was studied.Both hydrocarbon vapors' permeation exhibited pressure dependence, with propane showing the greatest variation over the same range.In the case of the mixture separation study, the achieved degree of separation was lower than would be predicted on the basis of the pure component permeation constants. Moreover, the total flow of vapor through the film was greater than would be expected on the basis of the individual gas flows. This was attributed to an anomalous diffusion phenomenon of ethane in the presence of dissolved propane due to a plasticization of the polymer network.

ISSN:0001-1541    

DOI:10.1002/aic.690160307

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractAn adiabatic loop reactor was operated at naturally unstable steady states in experiments employing the reaction between sodium thiosulfate and hydrogen peroxide in aqueous solution. The unstable states, the intermediate states in a multiple state regime, were stabilized by manual manipulation of the recycle ratio. Resulting temperature data agreed well with those predicted from a plug‐flow model. Observations of the transient response to small disturbances from the intermediate states verified that they were indeed unstable as had previously been predicted theoretically. Cursory attempts to stabilize the system by means of automatic feedback control employing a three‐mode controller were unsuccess

ISSN:0001-1541    

DOI:10.1002/aic.690160308

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractThe light intensity distribution in a perfectly mixed photoreactor has been studied experimentally and analytically. Experimental measurements of intensities within the reactor were made with a specially designed light probe. These data were then used to test the validity of a model which treats the ultraviolet lamp as a linear source radiating in all directions. It was found that this model, which seems appropriate and allows reasonable computations, is somewhat in error owing to the neglect of the finite size of the lamp and the existence of reflection and refraction effects within the reactor. An empirical correction function was determined for use with the model which then yields predictions in close agreement with experimental data when the reactor is filled with a light absorbing liquid.

ISSN:0001-1541    

DOI:10.1002/aic.690160309

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractA numerical method for solving a class of nonlinear optimal control problems is presented. The approach reformulates the associated two‐point boundary value problem as a multidimensional minimization problem. This problem is, in turn, solved by using the method of Davidon‐Fletcher‐Powell. The one‐dimensional minimization problem implicit in the implementation of the Davidon‐Fletcher‐Powell algorithm is handled with the Fibonacci search technique. Several examples are presented to demonstrate the effectiveness of the method for problems with and without magnitude constraints on the control

ISSN:0001-1541    

DOI:10.1002/aic.690160310

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractThe classical emulsion is made up of drops of one liquid dispersed in a containing liquid. Under certain circumstances, however, some of the containing phase may form drops within the drops of the dispersed liquid, giving rise to a structure known as a double‐multiple emulsion. This study was an investigation of the hydrodynamic formation of these structures.Double‐multiple emulsions were produced by using both transient and steady state liquid injection, with a cylindrical jet configuration. Analysis of the spray was by means of high‐speed photography.The distribution of the large drops and that of the included drops were both found to be represented satisfactorily by a log‐normal probability function. A simplified model based on the use of nozzle parameters satisfactorily correlated percent included area and volume as a function of Reynolds number and Weber number. Large dispersed phase drops contained proportionally many more inclusions than did the smaller sizes.The mechanism of inclusion formation was found to involve the drawing out of a ligament or sheet from the flowing jet, followed by the recoalescence of the free end of this ligament or sheet with the main jet body, entraining in the process a portion of the containing phase. Thus, the inclusions predate the formation of the drops of the dispersed phase from the jet dis

ISSN:0001-1541    

DOI:10.1002/aic.690160311

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effects of surface‐active agents on the stability of a liquid film is reinvestigated. The present analysis differs from the previous works in the treatment of the surface boundary conditions. The well‐known damping and stabilizing effects of surface‐active agents are shown to be due to the redistribution of surface material caused by wave motions and diffusion. The equations of neutral stability for both cases of soluble and insoluble surface‐active agents are o

ISSN:0001-1541    

DOI:10.1002/aic.690160312

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractLiquid‐phase Peclet numbers have been measured for 1/4 in. Raschig rings with countercurrent air flow in a 2 in I.D. column. The response curve has been analyzed by a computer program, since the output data was collected directly on paper tape. The Peclet number calculated from a moments analysis is considered unreliable, and the diffusion model can be rejected for the liquid phase. If the Peclet number is calculated by a least‐squares fit, and if the result is forced through the peak in the response curve, then a correlation for over one hundred runs with gas flows from 0 to 99% of flooding is given by Equations (7) and

ISSN:0001-1541    

DOI:10.1002/aic.690160313

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY