摘要:

AbstractA non‐disturbing technique has been used to measure turbulence parameters in a smooth pipe and in two randomly roughened pipes at the same apparent wall shear.Near the wall, large eddies are significantly more intense in smooth than in rough pipes while the small eddies are more intense in rough than in smooth pipes. No viscous sublayer was visible in the rough pipes. In the core, large apparent differences in large scale eddy structure were found between rough and smooth tubes, but the differences probably result from the inappropiate inclusion of dissipation due to form drag in u

ISSN:0008-4034    

DOI:10.1002/cjce.5450500501

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractA new model has been formulated and analyzed which accounts for the deformation of a drop in response to the pressure distribution in the draining film between it and a rigid plane. The rate of approach is related to the pressure distribution and drop shape. When the nonlinear partial differential equations are written in dimensionless form, one dimensionless group, β = Δρgb/σ2, arises which represents the ratio of gravity forces to surface forces. Only β need be specified to solve these equations; viscosity enters only as a scaling factor on time. The equations were simplified to ordinary differential equations by assuming that the rate of change of shape was small relative to the change in position. Numerical soliitions were obtained from β = .15 to 10−3using an iterative Runge‐Kutta procedure at each s

ISSN:0008-4034    

DOI:10.1002/cjce.5450500502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThis article considers possible erxors in experiment or analysis and alternative methods of data treatment for a falling coaxial cylinder viscometer. The viscometer uses a weighted rod falling into a polymer melt contained in a closed end concentric cylinder. Flow relations can be solved for non‐Newtonian fluid response in steady, simple shearing flow. Although the rod fall is found not to be steady, as assumed, this produces negligible error in the computed flow curves. Consistent flow curves which were independent of apparatus geometry were obtained by a method in which instantaneous rod velocities were estimated graphically from raw data and an end correction was taken into accoun

ISSN:0008-4034    

DOI:10.1002/cjce.5450500503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThe flow behavior of polymeric fluids in tubes can be determined from measurements of the radial stress profile in the flow direction. This subject, the focus of our research, will be examined in Part II of this communication.Part I describes a research designed to test the accuracy of stress measurement with pressure transducers in a variety of recess mount geometries.No mountgeometry errors were detected for the fluids used in this work over a shear rate range of 1 to 2000 sec−1. Part I also contains a survey of the literature and theoretical considerations pertinent to the entire wor

ISSN:0008-4034    

DOI:10.1002/cjce.5450500504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractExtensive pressure profile data were compiled for a 16.5% polyisobutylene solution in mineral spirits. Values of stored elastic energy obtained from these data compare favorably with those ascertained from die swell and from entrance correction methods. The viscometric normal stress differences were significantly larger than the shear stress and, particularly, the second normal stress rose to a maximum where it was an order of magnitude larger than the first normal stress difference. Time constants calculated from swell decay and entrance‐borne elastic stress relaxation are essentially the same and show an approximate inverse relation to the shear rat

ISSN:0008-4034    

DOI:10.1002/cjce.5450500505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractA new semi‐continuous dilatometer which does not have the major drawbacks of the previous model was designed, constructed and tested, using the systems benzene‐cyclohexane and cyclohexane‐ethanol. The volumes of mixing of five systems made of n‐alcohols and cyclohexanc: were determined

ISSN:0008-4034    

DOI:10.1002/cjce.5450500506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractA model is developed of gas liquid contactors in which packing pieces are maintained in the fluidized state. The model proposes that the column can exist in either of two modes, namely fluidisation without flooding and fluidisation due to incipient flooding. The mode of operation established depends primarily on the packing density and to a lesser extent on the packing size, liquid flow and liquid properties. Equations predicting the transition from one mode to the next are developed. The inherent advantages of operating in the “incipient flooding” mode are stressed. It is argued that the pressure build up associated with flooding will be sufficient to support the weight of packing pieces and the liquid in the column. At this stage, rather than reject counter current flow (true flooding) the bed expands to maintain a state of incipient flooding. In this way counter current flow can be maintained in a situation well above the normal flooding point. This explains the high performance of such un

ISSN:0008-4034    

DOI:10.1002/cjce.5450500507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractElutriation can be used as a convenient method for classification of particles. However, it has been observed that complete elutriation is not possible. Elutriation stops when the concentration of the elutriating component in the bed reaches an equilibrium value. The rate equation for elutriation has been found to be analogous to that of a first order reversible chemical reaction.In this paper two correlations—one for evaluating the equilibrium bed concentration and the other for the elutriation rate constant have been proposed by relating these quantities with the relevant system parameter

ISSN:0008-4034    

DOI:10.1002/cjce.5450500508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThe problem of physical separation of solids from liquids in very dilute concentrations by hydrocyclone concentration is considered in two parts. First, the effect of feed concentration, volume split, feed flowrate, cone angle, inlet diameter and vortex finder length on separation efficiency and energy loss are investigated. The relationship between the separation efficiency; and the energy loss is also studied.Secondly, the effect of three different designs of body shape on the separation efficiency and energy loss is investigated.In this study statistical concepts are used extensively in the design of experiments and the analysis of experimental results.

ISSN:0008-4034    

DOI:10.1002/cjce.5450500509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractAn analytical solution and method of calculation is presented for a cascade of N perfectly mixed batch extractors operating counter‐currently, for spherical solid particles, with parameters which may vary for each extractor.The results for the case of constant and equal parameters along the complete cascade are presented in dimensionless plots; N varies from 1 through 10.The practical interest of these diagrams lies in their use in design and/or in foreseeing the behavior of a cascade when its parameters undergo variations.A sample calculation is include

ISSN:0008-4034    

DOI:10.1002/cjce.5450500510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY