ISSN:0008-4034    

DOI:10.1002/cjce.5450690601

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe complete equations of motion and continuity have been solved numerically using the finite element method for the flow of power law liquids through assemblages of rigid spherical particles. The inter‐particle interactions have been simulated using the free surface cell model. Extensive results on drag coefficients have been obtained under a wide range of physical and operating conditions (0.9999 ≥ 0.3), 1 ≥n≥ 0.4 and 20 ≥Re≥ 1. The observed dependence of drag coefficient on voidage and non‐Newtonian flow behaviour index have been explained qualitatively with the aid of order of magnitude considerations. Finally, the theoretical predictions have been validated using suitable experimental data available in t

ISSN:0008-4034    

DOI:10.1002/cjce.5450690602

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

年代:1991

数据来源: WILEY

摘要:

AbstractA quantitative criterion distinguishing stable from unstable transitional packed bed flow in standpipes is presented. This criterion can be used as an working guideline in actual standpipe operation. A fundamental and simple model based on stress free surface (SFS) theory has been developed. This model also provides a quantitative prediction method for the standpipe voidage.

ISSN:0008-4034    

DOI:10.1002/cjce.5450690603

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe flow structure of the dispersed gas phase within an aerated stirred tank reactor of pilot scale (600L) has been investigated by means of a new ultrasound reflection technique. A compact implementation of the new measuring technique is described in this article. It allows the investigation the flow structure of the dispersed gas phase in real multiphase flows within arbitrary large reaction vessels. Measurements have successfuly been performed even in complex biotechnological and chemical production systems. The measuring device exploits the Doppler–shift of ultrasound pulses upon reflections at the surfaces of moving bubbles. Only a single measuring probe needs to be introduced into the dispersion. Bubble velocity distributions can be obtained within a few minutes, even during production processes in highly viscous media. The device is simple to use, since it is fully automized by means of integrated microprocessor

ISSN:0008-4034    

DOI:10.1002/cjce.5450690604

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

年代:1991

数据来源: WILEY

摘要:

AbstractGas holdup and liquid circulation time were measured in a down flow jet loop reactor for air–water system. It was observed that the circulation time decreases with an increase in nozzle diameter, draft tube to column diameter ratio and liquid velocity. Th gas holdup increases with an increase in gas and liquid velocities. The optimum draft tube to column diameter ratio was found to be 0.438. Correlations for gas holdup and circulation time involving operational and geometrical variables are presente

ISSN:0008-4034    

DOI:10.1002/cjce.5450690605

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

年代:1991

数据来源: WILEY

摘要:

AbstractAnalytical solutions are presented for temperature and moisture distributions in a cylindrical capillary‐porous body using Luikov's model and employing a solution technique based on the decoupling of the simultaneous heat and mass diffusion problems. The relative importance of the dimensionless parameters governing drying is presented and a comparison of temperature and moisture profiles for the cylinder and the slab is give

ISSN:0008-4034    

DOI:10.1002/cjce.5450690606

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe present paper deals with the investigation of thermocapillary and natural convection by applying a white light‐sheet technique for the simultaneous determination of the velocity and the temperature field. The oscillatory Marangoni convection has been visualized with differential interferometry. Streamlines, velocity profiles and isotherms are presented and discussed. A complete separation of a surface tension driven convection roll of hot fluid in the boundary layer and a buoyancy driven convection roll of colder fluid in the liquid volume was discovered. For large driving forces (large Marangoni number) inertia becomes effective and the interface becomes the source of localized eruption

ISSN:0008-4034    

DOI:10.1002/cjce.5450690607

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

年代:1991

数据来源: WILEY

摘要:

AbstractA detailed numerical study has been performed to examine the heat transfer enhancement through latent heat transport, in conjunction with the evaporation of a liquid film, in laminar mixed convection channel flows. Results for Nusselt numbers are presented for the air–water and air–ethanol systems under various conditions. Considerable augmentation in heat transfer due to the exchange of latent heat during the evaporation process was clearly demonstrated. The results show that the heat transfer is dominated by the transport of latent heat excha

ISSN:0008-4034    

DOI:10.1002/cjce.5450690608

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe predictions of two commonly used fouling monitoring devices, namely a heated rod in an annulus and a coiled wire in cross‐flow are compared. As fouling fluids, heptane with dissolved styrene (to simulate chemical reaction fouling), heptane with suspended particles (to simulate particulate fouling) and Kraft pulp black liquor (where both the above fouling mechanisms may occur) have been use

ISSN:0008-4034    

DOI:10.1002/cjce.5450690609

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe solvent extraction area is perceived by some chemical engineers as being mature and fully developed. The present review shows that this is not the case. Many chemical engineering problems must be solved before equipment can be confidently designed from first principles. The review also outlines progress in extraction process chemistry, and in new techniques such as membrane extraction.

ISSN:0008-4034    

DOI:10.1002/cjce.5450690610

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

年代:1991

数据来源: WILEY