摘要:

AbstractWettability plays an important role in a number of industrial applications. Often it becomes desirable to control contact angles (wettability). For this purpose, two techniques for altering the contact angles of glass beads are described. These involve chemisorption of Silicones or Hexamethyldisilazane (HMDS) on glass surfaces.The results of measured contact angles on treated glass beads indicate that by carefully controlling the treating procedure, it is possible to obtain the desired wettability.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530101

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe unsteady‐state behaviour of a reciprocating plate column in which adjacent plates move out of phase with each other has been studied experimentally by determining responses to step changes.The one‐dimensional, two‐parameter model developed, leading to a system of differential equations with time‐dependent coefficients, was simplified to allow parameter estimation in the Laplace domain. Special features of the experimental technique for obtaining instantaneous values of the tracer concentration which closely approximate to the average for a column cross section are described; the limitations of parameter estimation in the Laplace domain are di

ISSN:0008-4034    

DOI:10.1002/cjce.5450530102

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe results of a fluid‐particle heat and mass transfer study in air spouted beds of silica gel and activated coal particles, using a 9 cm I.D. column with a 30° and 90° conical base, are reported. The effects of gas velocity, particle size, bed depth and cone angle on the heat and mass transfer coefficients are discussed. Equations correlating heat and mass transfer coefficients have been established. The ratio (jn)s/(jD)8has been found to be dependent on the Reynolds number and the system of spout

ISSN:0008-4034    

DOI:10.1002/cjce.5450530103

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

年代:1975

数据来源: WILEY

摘要:

AbstractHeat transfer from a vertical grid jet within a 2 ft diameter and 4 ft deep fluidized bed of cracking catalyst was studied. The test nozzle diameter was varied from ¼ to 1 in. and the nozzle velocity from 50 to 250 ft /sec which is within the range of industrial practice. The axial temperature data have been related to a Froude, a Reynolds and a Nozzle number:In (δT/δTo) = –58.1 Fr−0.562No1.08Re−0.112A simple jet quenching model yielded heat transfer coefficients between the fluid bed and grid jet which ranged from 300 to 1200 Btu/

ISSN:0008-4034    

DOI:10.1002/cjce.5450530104

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

年代:1975

数据来源: WILEY

摘要:

AbstractMeasurements have been made of the rate of mass transfer of dissolved oxygen to the walls of 5 cm diameter horizontal pipes carrying aqueous slurries of sand and iron ore, in the concentration range 10 — 20 vol % at velocities up to twice the critical value for deposition. The results which show that the suspended particles greatly increase the rate of mass transfer are discussed in terms of the analogies and are compared with the results of previous workers for heat and momentum transfer. In the case of mass transfer in systems with high Schmidt numbers it appears that there is a specific effect of the solid particles relating to the disruption of the viscous sub‐la

ISSN:0008-4034    

DOI:10.1002/cjce.5450530105

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

年代:1975

数据来源: WILEY

摘要:

AbstractHorizontal and vertical mapping of the cathode mass transfer coefficient was used to compare the hydrodynamics of full height model electrowinning cells employing either natural convection or two methods of forced convection. The most sgnificant improvement in performance was achieved with uniform agitation resulting from sparging gas over the cathode surface.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530106

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

年代:1975

数据来源: WILEY

摘要:

AbstractIonic mass transfer coefficients between the wall of a 2.081 inch tube and liquid fluidized beds of lead glass, soda glass and lucite spheres have been measured using the diffusion‐controlled reduction of ferricyanide ion at a nickel cathode for porosities 0.90 to 0.45 and Schmidt numbers 580 to 2100.The developed fluidization mass transfer coefficient for 41

摘要:

AbstractSorptions of six pure hydrocarbons and five of their binary mixtures in low density polyethylene have been measured. Composition of the binary mixture sorbed has been determined experimentally by a direct method. Selectivity due to sorption has been shown to constitute a major portion of the permselectivity.Correlations have been developed to predict the quantity and composition of the binary mixture sorbed in the polymer at any temperature, when the pure compound sorptions at some temperature are known.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530108

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe purpose of this study is to obtain generalized drying curves which can be used in the prediction of drying times of porous solids in the falling‐rate period. The drying model introduced assumes that the movement of moisture in the solid body is by capillary motion, and that the major resistance to heat and mass transfer lies on the boundary layer at the solid surface. It has been applied to the drying of gypsum particles of various sizes in a rotary dryer at different feed rates and gas temperatures. The results show that the deviation between the experimental data and the ones predicted from theory is very small. The deviation increases at low moisture concentrations which may indicate that internal resistance to moisture flow starts to dominate the drying phenomen

ISSN:0008-4034    

DOI:10.1002/cjce.5450530109

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

年代:1975

数据来源: WILEY

摘要:

AbstractThis paper presents a resume of literature on theories and mathematical models for drying of rigid porous materials. Key work on drying by soil physicists has been neglected in the engineering drying literature. We have included these works here to bring this literature to the attention of engineers.A new and general model for moisture and energy transport in rigid porous media during drying is presented. It is demonstrated that under certain simplifying assumptions, the general model reduces to less general models which have previously been proposed.Experimental and simulation results are given for the drying of Valentine sand. Under the drying conditions studied, the drying rate during the falling rate period is controlled by the capillary flow of water to an evaporation zone in the porous media.The models simulated here are of varying complexity and rigor. The capabilities and limitations of these models are discussed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530110

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

年代:1975

数据来源: WILEY