摘要:

AbstractCorrelations have been derived, by both geometrical arguments and empirical treatment of data, for the bulk void fraction in a fixed bed. The void fraction has been correlated as a function of particle‐to‐tube diameter ratio for packings of spheres and equilateral solid cylinders. Prediction of void fraction for equilateral hollow cylinders can be made from the solid cylinder correlation, provided a correction factor is included that allows for internal voidage and interpenetration of packi

ISSN:0008-4034    

DOI:10.1002/cjce.5450660501

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

年代:1988

数据来源: WILEY

摘要:

AbstractRheological measurements of polyisobutylene solutions are presented. A mineral oil of low viscosity has been used as solvent. The combined effects of concentration, molecular weight and temperature were studied. It is found that the rheological data, when plotted as N1λE/(η‐ηs) versus λEγ fall on a master curve over several decades of the dimensionless shear rate, irrespective of temperature, polymer concentration and molecular weight. The findings of this work can be used to address the problem of hydrodynamic lubrication of a journal bearing using a viscoelastic lub

ISSN:0008-4034    

DOI:10.1002/cjce.5450660502

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe entry length for horizontal slurry pipeline flows has been determined experimentally using a pipeline of diameter 50 mm. Concentration and velocity distributions have been measured in the vertical direction at positions 6, 50 and 185 diameters downstream of the entrance.The measurements show that the entry length is of the order of 50 pipe diameters for sand slurries. High particle settling velocities give somewhat shorter lengths than intermediate settling velocities. With lower density polystyrene particles for which dispersive effects are important, the entry length is significantly greater than 50 diameters. The velocity distributions show that the velocity profiles develop concurrently with the concentration profiles. For sand slurries, a two‐dimensional simulation gives a satisfactory representation of the developing concentration profile

ISSN:0008-4034    

DOI:10.1002/cjce.5450660503

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe force‐balance model, originally developed for coarse‐particle slurries, has now been extended to slurries of finer particles susceptible to turbulent suspension. The analysis involves a turbulent dispersive force — an equivalent body force between the fluid and solid phases. The use of this force, together with the intergranular stresses for contact‐load particles, allows the calculation of concentration and velocity profiles which vary continuously with height. The calculated profiles are found to be in generally good agreement with experimental data from the Saskatchewan Research

ISSN:0008-4034    

DOI:10.1002/cjce.5450660504

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

年代:1988

数据来源: WILEY

摘要:

AbstractFlocculation experiments have been carried out using cationic polymers and kaolin suspensions. The effects of polymer dosage, kaolin concentration, pH, agitation, molecular weight and charge density of polymer, concentration of polymer solution, and addition of inorganic salt were systematically examined. It was found that two optimal points of polymer dosage exist between 0 to 8 × 10−3kg/kg‐kaolin. The flocs formed at each optimal dosage are different from each other in shape and in size. It is concluded that these two kinds of flocculation are respectively caused by the neutralization of the surface charge of the particles due to the adsorption of free polymer and by the incomplete neutralization owing to the presence of polymer drop

ISSN:0008-4034    

DOI:10.1002/cjce.5450660505

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

年代:1988

数据来源: WILEY

摘要:

AbstractNew expressions for the maximum spoutable height and spout pressure drop ratio are developed for fine particles spouted in water. The maximum spoutable height in both water and air systems is found to be dependent upon two dimensionless parameters, β and ALim. For fine particles spouted with water, the dimensionless pressure drop ratio depends only upon the voidage, ϵ at the bottom of the spou

ISSN:0008-4034    

DOI:10.1002/cjce.5450660506

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

年代:1988

数据来源: WILEY

摘要:

AbstractGood grid design is essential for the satisfactory performance of large gas fluidized beds and requires the accurate prediction of the grid pressure drop. Experiments conducted with various perforated plate distributors in a 0.6 m I.D. fluidized bed column showed that the presence of fluidized solids could increase the grid pressure drop by more than 100%. This increase was around 25% for a grid pressure drop to bed pressure drop ratio of 0.4. It was greatly affected by the bed height. An investigation of various possible causes for this increase demonstrated that it is primarily caused by the backflow of fluidized solids into the grid holes under the influence of waves at the bed surface.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660507

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe trajectory of clusters ejected in the freeboard by gas bubbles bursting at the surface of fluidized beds is used to propose a new way to determine the transport disengaging height (TDH). As the effect of the drag force is negligible for the largest clusters, the maximum height they reach in the freeboard is directly proportional to the square of their ejection velocity. The maximum heights thus calculated are in good agreement with experimentalTDHvalues from the literature. A procedure is given to compute theTDHfrom this simple expression.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660508

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

年代:1988

数据来源: WILEY

摘要:

AbstractThrough the exact number of contact points between the two components of a solids system, the reactivity of the solids is expressed in terms of the molar ratio, the particle size ratio and the nature of the reacting system. The theory is confirmed by existing experimental data, revealing that the contact points play an important role for wide ranges of reactivity of solids.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660509

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

年代:1988

数据来源: WILEY

摘要:

AbstractAnalysis of mass and energy balance equations for gas‐solid reactions are of particular importance in the interpretation of micro scale thermo‐gravimetric analysers, laboratory scale drop tube reactor data, and in the modeling of industrial scale reactors. In the present work we investigate the solutions of mass and energy balance equations for highly porous fine particle gas‐solid reactions in a relatively slow chemical reaction regime (chemical reaction control). Linearization of balance equations around the steady‐states does not provide a satisfactory approximation of the phenomena under consideration, implying that higher order terms are needed for a more accurate description of the

ISSN:0008-4034    

DOI:10.1002/cjce.5450660510

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

年代:1988

数据来源: WILEY