摘要:

AbstractA review is performed to trace how fissured porous media arise in nature. It is found that packed beds resemble fissured porous media. The range of multiple flow time‐scales inherent in such media becomes larger as the particle size range becomes broader, resulting in flow nonuniformities. The status of experimental measurements of voidage and flow nonuniformities is assessed. Some of the difficulties associated with modeling of the multiple flow time‐scales are discussed, and a tentative model is propo

ISSN:0008-4034    

DOI:10.1002/cjce.5450600112

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

年代:1982

数据来源: WILEY

摘要:

AbstractMarker nephelometry was used to study the nozzle fluid concentration field of free swirling turbulent jets. Swirl was generated by guide vanes in a 7.14 cm diameter nozzle with swirl numbers of 0.22, 0.36, 0.61 and 0.68 as determined by direct measurement of the linear and angular momentum fluxes for the jets. The parameters measured include those describing the self‐preserving forms of the mean concentration field, the intensity and integral scale of the concentration fluctuations, and the intermittency for the jets without internal recirculation (swirl number<0.6). Results show that swirling jets without internal recirculation are very similar in structure. The data for the two jets with internal recirculation zones are given as contour maps describing the mean concentration and fluctuation intensity fields. The results as a whole describe jets with weak to moderate swirl and indicate trends to be expected for jets with strong swir

ISSN:0008-4034    

DOI:10.1002/cjce.5450600113

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

年代:1982

数据来源: WILEY

摘要:

AbstractIn horizontal dense‐phase slurry transport the pressure gradient is the sum of two components. The particle‐contact component, which was evaluated previously, is independent of flow velocity. It is now shown that the second component can be found in terms of a friction factor which depends on a Reynolds number based on flow velocity and particle diameter. The form of the dependence has been evaluated from theoretical considerations, and the results show a gratifying accord with the experimental data. In addition to dense‐phase flow, the findings should be applicable to other cases with a sliding bed of s

ISSN:0008-4034    

DOI:10.1002/cjce.5450600114

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe effect of interfacial tension gradients on creeping flow past a fluid sphere (bubble or drop) in a non‐Newtonian fluid is investigated. The drag force and the Sherwood number for contaminated fluid spheres moving in a non‐Newtonian fluid are obtained by an approximate solution of equations of motion in the creeping flow regime. It has been found that surface‐active agents decrease both the terminal velocity and the mass transfer rate. The influence of the flow index of the power‐law on both the drag coefficient and the Sherwood number is superimposed over the influence of the interfacial tension gradient.Comparisons between the present analysis and the available experimental data in the literature show reasonable agreement for the terminal velocity and the Sherwood

ISSN:0008-4034    

DOI:10.1002/cjce.5450600115

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

年代:1982

数据来源: WILEY

摘要:

AbstractA semitheoretical correlation based on an extension of the random length, random angle statistical model of Davidson (1959) is developed which predicts liquid film mass transfer coefficients in a column packed with partially wetted Raschig rings.The method takes into account the ring size and the mixing which occurs at the packing junctions and allows an estimation of the effective length of a packing piece for a particular liquid viscosity. Predicted values of mass transfer coefficients are in good agreement with the experimental values obtained for the carbon dioxide‐water and carbon dioxide‐aqueous glycerol systems at 25°C reported by Mangers and Ponter (1980b) and other systems reported by Sherwood and Holloway (1

ISSN:0008-4034    

DOI:10.1002/cjce.5450600116

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

年代:1982

数据来源: WILEY

摘要:

AbstractMass transport patterns in natural convection generated in non‐flow cells at horizontal electrodes have been studied by an electrochemical visualization technique. Sharp colour changes in the thymbol‐blue indicator during electrolysis, due to local pH‐variations occurring in the cathodic boundary layer allow direct tracing of the propagation of flow filaments into the electrolyte bulk. The results provide direct evidence for the enhancing effect of magnetic fields on electrolytic mass transport rates and for the existence of horizontal velocity components of appreciable size at the convective sur

ISSN:0008-4034    

DOI:10.1002/cjce.5450600117

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

年代:1982

数据来源: WILEY

摘要:

AbstractLes vitesses moyennes, les fluctuations de vitesse, la capacité de pompage, les intensités de turbulence du courant de refoulement d'une turbine à barreaux croisés dans une cellule de flottation ont été déterminés par anémométrie à film chaud à différentes vitesses de rotation. Les influences du nombre de barreaux de la turbine et de la viscosité du liquide ont

ISSN:0008-4034    

DOI:10.1002/cjce.5450600118

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

年代:1982

数据来源: WILEY

摘要:

AbstractLes influences du nombre de barreaux d'une turbine à barreaux croisés et de la viscosité du liquide sur les résultats de l'analyse spectrale du signal anémométrique dans une cellule de flottation ont été déterminées. Les spectres de fréquence et coefficients d'autocorrélation, les échelles intégrales temporelles et spatiales, le coefficient de diffusion turbulente, le taux de dissipation locale d'énergie et la microéchelle de turbulence ont été précisés et leurs caracté

ISSN:0008-4034    

DOI:10.1002/cjce.5450600119

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

年代:1982

数据来源: WILEY

摘要:

AbstractPolymers were used in the experiments to determine optimum type and dosage requited for effective treatment of an industrial effluent containing nitrocellulose fine particles. It was found that (a) contact flocculation filtration was not effective for treating the nitrocellulose‐manufacturing wastewater due to the high initial turbidity; (b) mixing, flocculation, and settling of the wastewater with cationic polyelectrolyte and bentonite clay gave greater than 95% turbidity removal; (c) with the same optimum chemical dosages, mixing, flocculation and centrifugation also gave about 97% turbidity removal; and (d) with the same optimum chemical dosages, mixing, flocculation, sedimentation and filtration removed 99.9% of the wastewater turbidit

ISSN:0008-4034    

DOI:10.1002/cjce.5450600120

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe transient behaviour of an internally‐recycled catalytic reactor has been studied accounting for the contributions from intraparticle diffusion, adsorption and surface reaction. Equations for the zeroth, first and second absolute moments of the break‐through curves are given in terms of the rate constants for the three elementary steps (first order processes are assumed throughout). The moments can be obtained from experimental break‐through curves and the rate parameters for adsorption and surface reaction then evaluated from such data. Simplified equations also are derived for the case of insignificant chemical reaction and this case is used to test the method experimentally. Values of the hydrogen adsorption equilibrium constant for γ‐alumina supported Co Mo‐Ni catalyst ar

ISSN:0008-4034    

DOI:10.1002/cjce.5450600121

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

年代:1982

数据来源: WILEY