ISSN:0008-4034    

DOI:10.1002/cjce.5450640101

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe rheological behaviour of concentrated oil‐in‐water emulsions has been investigated using the Weissenberg Rheogoniometer. The oil concentration has been varied from 40 to 95 volume percent. The effects of shear rate and oil concentration on the viscosity have been determined. From the rheological data, the maximum attainable oil concentration in the emulsion has been estimated and is introduced as a parameter in the relationship between relative viscosity and oil concentration to account for certain variations in the emulsion characteristics. Empirical equations have been obtained which correlate zero shear rate viscosity and infinite shear viscosity as a function of reduced oil concentration. Comparison has been made between the emulsion viscosity and the solid‐liquid suspension viscosity at high dispersed phase concentration. Estimated maximum attainable oil concentration is found to be in close agreement with the actual maximum concentration that could be achieved experimen

ISSN:0008-4034    

DOI:10.1002/cjce.5450640102

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe variation in film thicknesshwith timetfor the approach of an infinite sphere to a plane horizontal surface (β = 1) or of two infinite spheres (β = 2) is given by:\documentclass[article]\pagestyle[empty]\begin[document]$$ t = (3\pi n^2 \mu a^2 /2\beta ^2 f)\ln (h_o /h)...............................(a) $$\end[document]For finite spherical caps with edge radiusrfthe variation is much more complicated and also involves the parameter S = βr2f/2aho. Fortunately, the gradient\documentclass[article]\pagestyle[empty]\begin[document]$$ - d(\ln h(/dt = (3\pi n^2 \mu a^2 /2\beta ^2 f)..........................(b) $$\end[document]is the same in both cases, providingtis large enough (the critical value oftincreases with decreasingS). A similar result is obtained if the spherical cap is approximated by a parabolic cap with apex curvature 1/aequal to that of the sphere. In both cases the variation in dynamic pressure close to the centre of the draining film is identical and independent of the radial position where the dynamic pressure falls to zero when the film thickness is small.MacKay and Mason (1961) measured the film thickness beneath a sphere of finite size approaching a horizontal plane and experimentally verified Equation (b). This does not however, as they assumed, prove the correctness of Equation (a), which only applies to infinite spheres. The more complicated equations describing the approach of finite spheres and parabolic caps are presented in this pap

ISSN:0008-4034    

DOI:10.1002/cjce.5450640103

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe hydrodynamic behavior of a bubble column has been studied for various Newtonian and non‐Newtonian liquids (water, glycerol, carboxymethylcellulose and polyacrylamide solutions). The mixing time, the power consumption, the circulation time and the gas hold‐up have been measured in a cylindrical column (diameter: 0.254 m, height: 0.9 m) for three air sparger plates with different numbers and distributions of 1 mm diameter orifices. It is shown that the mixing efficiency decreases as the viscosity or the shear‐thinning and elastic properties of the liquid increase. The viscosity of the liquid has little influence on the gas hold‐up which is, however, strongly affected by the sparger plate characteristics and increases as the liquid phase becomes more elastic. A model for predicting gas hold‐up is

ISSN:0008-4034    

DOI:10.1002/cjce.5450640104

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

年代:1986

数据来源: WILEY

摘要:

AbstractExperimental results on the discharge characteristics of concentric orifice meters placed in circular pipes carrying sediment‐laden flow in homogeneous and heterogeneous regimes are reported. The experiments were carried out using water as the carrying medium and sand and coal as the sediments. The data cover a range of concentration from 0.5% to 7.0% by volume. The analysis of the data has resulted in graphical predictors which enable determination of the discharge to fairly good accurac

ISSN:0008-4034    

DOI:10.1002/cjce.5450640105

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

年代:1986

数据来源: WILEY

摘要:

AbstractTwo‐phase pressure drop in a 93 mm diameter reciprocating plate column (RPC) was studied for the air‐water system, and to a lesser extent for air‐kerosene. Amplitudes (strokes) in the range 14 to 63.5 mm and frequencies from 0.75 to 4.0 Hz were investigated for between 2 and 10 brass plates with hole diameters from 3 to 8 mm and free flow area between 0.09 and 0.306. Continuous phase velocity was varied from 1.24 to 3.72 cm s−1and dispersed phase velocity varied from 0.04 to 5.10 cm s−1. The measured pressure head was subjected to a static head correction based on the measured holdup of the dispersed phase and densities of the phases. The data were correlated by regression analysis as a friction factor expressed in terms of loading ratio, Reynolds number and Froude number; they were also compared with an earlier theoretical prediction by Noh and Baird for single phase flow in a RPC. The two‐phase pressure drop was found to increase with agitation both in the mixer‐settler and emulsion regions and reached a maximum at vibrating speeds around 10 cm s−1. Beyond this point, it decreased in the unstable region preceding flooding. It was concluded that the RPC could be effectively used in the emulsion region for opti

ISSN:0008-4034    

DOI:10.1002/cjce.5450640106

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

年代:1986

数据来源: WILEY

摘要:

AbstractA 0.27 m diameter fluidized bed reactor has been designed to allow experimental measurement of the axial and radial mixing behaviour of the solids.A unique method has been developed which permits the continuous determination of solid tracer concentration with time at different radial and axial positions within the fluidized bed.Solids mixing has been described by a model in which vertical mixing is instantaneous and lateral mixing occurs by dispersion.The lateral solids dispersion coefficients have been evaluated at various operating conditions from the experimental results of tracer concentration versus time. Based on the results, a modification of an existing correlation is proposed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450640107

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

年代:1986

数据来源: WILEY

摘要:

AbstractAn airlift three‐phase reactor in which solid particles are fluidized in the riser by the recirculating liquid was developed. Three particle types of 1.7–8.6 mm in diam., porous and nonporous, spheres and cylinders, were studied in the water–air system. Little effect of the alumina porous particles (apparent density 1.47 × 103kg/m3) on the gas holdup and liquid superficial velocity was found. On the other hand, the heavier, nonporous ceramic particles (density 2.4 × 103kg/m3) had a significant effect on both design parameters. The axial distribution of particles was also a function of the particle density and liquid superficial v

ISSN:0008-4034    

DOI:10.1002/cjce.5450640108

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe Girdler–Sulfide (GS) heavy water production process has traditionally used tray columns because of their large size. In recent years, the chemical industry has extended the use of packing to larger columns because of economic and performance advantages. A pilot scale study was thus initiated to compare the hydraulic, mass transfer and heat transfer performance of an ordered bed packing (Mellapak) with sieve trays operating under GS process conditions. Mellapak offered lower pressure drops, higher throughputs and improved heat transfer over sieve trays. However, benefits to deuterium mass transfer were only marginal in large diameter column

ISSN:0008-4034    

DOI:10.1002/cjce.5450640109

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

年代:1986

数据来源: WILEY

摘要:

AbstractA theoretical model for deuterium exchange in the H2S/H2O system was derived to describe mass transfer in the bubble formation, bubble displacement and bubble breakup regions above a single‐hole tray in an 8 cm diameter transparent column. The model was applied to data measured at 31°C in the pressure range of 790 to 2000 kPa and in a wide range of gas and liquid flows. High speed cinematography was used to measure bubble diameters, bubble formation times and bubble contact times in the liquid, all of which are parameters in the mass transfer models.Results show that for single‐hole trays and the major part of mass transfer occurs in the upper surface of the froth where bubbles disengage from the liquid. However, when the same model is applied to pilot plant sieve trays, it is shown that the bulk of mass transfer takes place in the region where bubbles are ascending in the froth. The tray efficiencies predicted by the model agree well with measured va

ISSN:0008-4034    

DOI:10.1002/cjce.5450640110

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

年代:1986

数据来源: WILEY