摘要:

AbstractNew data on flow pattern transition for gas liquid flow in small diameter tubes (4 to 12 mm) is presented. The experimental results are compared with previously published models for horizontal and vertical flows considered to be valid for medium and large diameter pipes. The effect of surface tension which might be expected to be important in small diameter pipe flow has been found to affect only the stratified‐slug transition in horizontal flow. A modification to the model to include this effect is propose

ISSN:0008-4034    

DOI:10.1002/cjce.5450610501

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

年代:1983

数据来源: WILEY

摘要:

AbstractFilm thickness in horizontal annular flow in small diameter pipes (8‐12 mm) was measured as a function of circumferential position. In addition a simple analytical model for the prediction of the film thickness at the top and bottom of the pipe is propose

ISSN:0008-4034    

DOI:10.1002/cjce.5450610502

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

年代:1983

数据来源: WILEY

摘要:

AbstractMathematical models of heat transfer processes are usually studied using formulation that is unique in the mathematical sense. For example, in solving initial‐boundary value problems in conduction heat transfer, the mathematical model consists of the governing equation and initial and boundary conditions. An extension of such an approach by introducing the supplementary information (or data) concerning the process has been proposed here as a method for verifying the accuracy of the model equations. This means that the mathematical model consists of more equations than unknowns which leads in consequence to a finite set of probable solutions. A criterion for choosing the most probable solution has been proposed. Special attention has been paid to numerical formulation. Computational methods have been derived using the Lagrange multipliers. Theoretical considerations have been illustrated by computing the temperature distribution inside a laboratory combustion chambe

ISSN:0008-4034    

DOI:10.1002/cjce.5450610503

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

年代:1983

数据来源: WILEY

摘要:

AbstractA cocurrent flow of pure gaseous SO2and liquid H2O was used to fluidize particulate zinc in order to produce industrial concentrations of zinc hydrosulphite, ZnS2O4. Based on transport phenomena and reaction kinetics, measured concentration profiles of both absorbed SO2and reacted Zn, as well as mean solid holdups, were best predicted by a combined bubble‐wake and axially dispersed plug flow mode

ISSN:0008-4034    

DOI:10.1002/cjce.5450610504

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

年代:1983

数据来源: WILEY

摘要:

AbstractHeat transfer rates were measured to a commercial paraffin wax undergoing freezing and melting in vertical cylindrical containers. Circular, square and axially‐partitioned cylinders were used. Natural convective motions were followed using tracer particles in a visual study of melting. Freezing fluxes were well predicted by a quasi‐steady conduction model. Melting fluxes were enhanced by natural convection. A melting model employing an effective thermal conductivity predicted melting fluxes satisfactor

ISSN:0008-4034    

DOI:10.1002/cjce.5450610505

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

年代:1983

数据来源: WILEY

摘要:

AbstractBubble formation on the grid in a three‐dimensional fluidized bed was studied by means of a mini‐capacitance probe coupled with the on‐line correlation technique. Experiments were carried out in fluidized beds with relatively shallow bed heights of 50, 80 and 100 mm. The present study has confirmed the well‐known observation that bubbles detach from the end of a jet with a formation frequency of about 19 Hz. The stochastic process proposed, more specifically, a renewal counting process corresponding to the gamma distributed inter‐arrival times, has been found to describe the process of bubble forma

ISSN:0008-4034    

DOI:10.1002/cjce.5450610506

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn a variety of catalytic processes dealing with porous catalysts, bidisperse solids arc used. In such systems, it is important to know the adsorption rate together with the diffusion rate in the macro and micropores of the porous solid. In this work, the Dog'u‐Smith (1975) single pellet pulse response method has been used for the simultaneous evaluation of the adsorption and the macro and micropore diffusion parameters in bidisperse porous catalysts. It has been shown that the method succesfully can be applied for fast and accurate evaluation of these parameters. Equations relating the adsorption and diffusion parameters to the measurable properties of the response peak have been derived for a bidisperse pellet.The method experimentally was tested for ethylene adsorption on α‐alumina at 45°C and atmospheric pressure. For a pellet of total porosity 0.73 and macroporosity 0.32, the effective macro and micropore diffusivities and the adsorption equilibrium constant were determined as 0.0334 cm2/s, 8.9×106cm2/s and 25 cm3/g, respec

ISSN:0008-4034    

DOI:10.1002/cjce.5450610507

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

年代:1983

数据来源: WILEY

摘要:

AbstractA simple reliable method to measure Residual Adsorption Capacity (RAC) of charcoal adsorbers on which a gas is physisorbed has been developed. The method consists of passing a pulse of weakly adsorbed gas(es) through the adsorption filter(s) and measuring the retention time. This retention time is then correlated to the residual adsorption capacity. In order to predict the retention time‐RAC relationship for filters with various configurations and bulk densities, this pulse test was mathematically modeled. The numerical solution of the model involved estimating the transport rate parameters, using existing correlations and the moment technique. A perturbation analysis indicated that the accuracy of the model is closely associated with the estimates of adsorption equilibrium constant and the intraparticle diffusion coefficient of the test gas. The model is shown to be accurate in predicting the RAC of an adsorber under dry and humid conditions from a limited data se

ISSN:0008-4034    

DOI:10.1002/cjce.5450610508

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

年代:1983

数据来源: WILEY

摘要:

AbstractFor oil sand extractions with microemulsions it is important to disperse large quantities of light hydrocarbons in an aqueous medium. Fundamental studies on the properties of 2‐butoxyethanol (BE) and diethylmethylamine (Et2McN) in water suggest that these two liquids could be more effective cosurfactants than the usual alcohols used for this purpose. The phase diagrams of microemulsions using BE and Et2MeN as cosurfactants, combined with typical ionic and non‐ionic surfactants and typical aliphatic and aromatic hydrocarbons, were therefore investigated and compared with microemulsions based on n‐butanol. Although the phase diagrams depend significantly on the nature of the surfactant and of the oil, the monophasic region generally increases with the cosurfactant in the order n‐butanol

ISSN:0008-4034    

DOI:10.1002/cjce.5450610509

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

年代:1983

数据来源: WILEY

摘要:

AbstractAqueous solutions containing the active components of microemulsions, i.e. surfactants and polar cosurfactants, are not effective in dissolving bitumen and consequently in extracting tar sands. On the other hand, if a light hydrocarbon such as benzene, toluene or cyclohexane is added to the active components, the microemulsion becomes a very effective extractant. To investigate this phenomenon, phase diagrams of pseudo‐ternary systems (active mixture‐hydrocarbon‐bitumen) were determined at 25°C and in some cases in the temperature range 25 to 80°C. In most experiments, the cosurfactant was taken as 2‐butoxyethanol and the hydrocarbon as toluene. Three surfactants were examined: cetyltrimethylammonium bromide, aerosol OT and sodium dodecylbenzenesulfonate. Various regions can be identified on the phase diagrams: suspensions of solid surfactants, microemulsions, stable and unstable emulsions. The extent of the various regions depends significantly on the relative concentrations of the various components. In general, the extent of the dispersed bitumen region increases with te

ISSN:0008-4034    

DOI:10.1002/cjce.5450610510

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

年代:1983

数据来源: WILEY