摘要:

AbstractA preliminary study is reported of the use of temperature gradients to accelerate the deposition of small particles from laminar air streams. It is shown that appreciable effects can be obtained even with small temperature gradients and particles as large as 30 μm. An empirical correlation is proposed for the thermophoretic force based on the present results and those published previously for smaller particles

ISSN:0008-4034    

DOI:10.1002/cjce.5450490501

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

年代:1971

数据来源: WILEY

摘要:

AbstractFour experimental aspects of momentum dissipation of grid jets in a gas fluidized bed of cracking catalyst are reported. First, an investigation was made into the radial distribution of axial momentum for air jets issuing from vertical long nozzles into a minimally fluidized bed. The theory of Abramovich was compared with these experimental results. Second, data on the distribution of axial momentum along the axis for vertical air jets issuing from single and multi‐hole grids were compared with previous work. Third, the axial dissipation of vertical air jets loaded with fluid cracking catalyst issuing into air and also into a fluid bed was studied. Finally, the shape of the boundary of a jet dissipating into a fluid bed was compared to that given by theor

ISSN:0008-4034    

DOI:10.1002/cjce.5450490502

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

年代:1971

数据来源: WILEY

摘要:

AbstractAn improved parametric method is presented for characterization of the flow geometry in the rectilinear flow of non‐Newtonian fluids in open and closed conduits of arbitrary crosssection and in purely viscous, inelastic flow of non‐Newtonian fluids through packed beds and porous media. In the new formulation, an infinite number of geometric parameters characterize the flow geometry. The actual number required in a particular application is shown to be determined by the fluid model equation representing the rheological behavior of the fluid. For Ostwald‐de‐Waele and Ellis fluids with flow behavior indices s = 1/n and α integers, the number of geometric parameters required to represent the relationship between flow rate and pressure drop is given by s + 1 and α + 1, respectively. The efficacy of the present method is demonstrated by comparisons with available results for various fluid models and flow g

ISSN:0008-4034    

DOI:10.1002/cjce.5450490503

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe discontinuity of terminal velocity versus bubble volume previously reported as taking place in viscoelastic liquids, was studied experimentally and theoretically. A comparison of terminal velocity data for gas bubbles and glass spheres in aqueous polymer (Separan‐AP30) solutions provides strong evidence that the discontinuity results from a change in interfacial conditions from “no‐slip” to free shear. A numerical solution of the creeping flow equations using an empirical curve fit for viscosity versus shear‐rate indicates that only a fraction of the experimentally observed velocity jump is due to the shear dependence of the viscosity alone (neglecting elastic effects). However, simple qualitative arguments seem to suggest that a relatively modest elastic contribution to the force balance on the bubble would be sufficient to account for the experimental obs

ISSN:0008-4034    

DOI:10.1002/cjce.5450490504

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe concept of the yield stress of a fluid is discussed and the principle methods which have been used to evaluate it are critically reviewed. It is shown that many factors can influence the determination of this parameter. Most of the existing methods determine some property near an interface or wall rather than the actual yield stress value which is a physical property of the fluid itself. A procedure and technique for measuring the actual yield stress of a substance is suggested which seems to eliminate most of the shortcomings of other methods.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490505

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe cylinder withdrawal theory for power‐law fluids proposed by Tallmadge has been compared with continuous withdrawal data in this work. Calculated withdrawal speeds differ greatly from measured values, although Tallmadge's gravity‐corrected theory for Newtonian fluids is in agreement with the present data on Newtonian fluids.Correlations similar to that of Goucher and Ward have been developed with the experimental data over a 400‐fold range of dimensionless withdrawal speeds. These correlations are applicable for prediction of non‐Newtonian liquid film thicknesses on vertical wires and also apparently for viscoelastic fluids like CMC solutions, but are not applicable for inelastic fluids like Carbo

ISSN:0008-4034    

DOI:10.1002/cjce.5450490506

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

年代:1971

数据来源: WILEY

摘要:

AbstractA study of the effect of liquid maldistribution on the performance of a gas absorber is reported. The experimental work was carried out using the carbon dioxide‐water system in a simulated packed column consisting of an ordered array of spheres. This device has been shown to closely approximate the behaviour of an actual column and permits the artificial manipulation of the liquid distribution. The results indicate that maldistribution causes only a small decrease in the mass transfer coefficient at low liquid flow rates, and has almost no effect at higher flows. A proposed iterative procedure for calculating the effect is presente

ISSN:0008-4034    

DOI:10.1002/cjce.5450490507

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe mass transfer characteristics of liquid‐liquid (horizontal) pipeline contactors were studied for the bubble and plug flow regimes. The contactors were operated co‐currently. The theory of mass transfer with chemical reaction was used to obtain values of physical mass transfer coefficient (kLa) and effective interfacial area(a)for a number of systems. In all the experiments the resistance to mass transfer was confined to the continuous phase. The effect of the flow rates and viscosities of the two phases, interfacial tension, contactor length, pipe diameter, the presence of solids,etc.on both,kLaandawas studied. The values ofkLaandawere found to vary from 1 to 50 × 10−3sec−1, and 0.4 to 25 cm−1, re

ISSN:0008-4034    

DOI:10.1002/cjce.5450490508

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

年代:1971

数据来源: WILEY

摘要:

AbstractOrganic sulphur compounds present in coal gas containing 15‐20% CO were effectively converted into H2S over a “Nimox” (nickel‐molybdenum) conversion catalyst. H2S was effectively removed by “Luxmasse”, a prepared iron oxide. The overall removal of organic sulphur depended upon the concentration of thiophene present. With only 10 ppm thiophene in the gas, the conversion of organic sulphur was 97% at 350°C after a single treatment. With six‐stage treatment at 350 psig, the final gas contained only 0.2 ppm total organic sulphur in the presence of 4

ISSN:0008-4034    

DOI:10.1002/cjce.5450490509

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of temperature on the rate of dissolution of gibbsite and boehmite in caustic soda solutions was studied in the temperature range 25‐100°C. The results fitted the Arrhenius rate equation and the activation energy was found to be 30.6 ± 0.9 k. cal/g‐mole for the gibbsite reaction and 29.4 ± 1.3 k. cal/g‐mole for the boehmite reaction. While the effect of temperature on the boehmite dissolution has not been reported before, the value of the activation energy for gibbsite was higher than previously reported values. Reasons for these differences are given and a consistent value of the activation energy was obtained which agreed both with experimental data for different gibbsite samples and with modified forms of the previously publis

ISSN:0008-4034    

DOI:10.1002/cjce.5450490510

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

年代:1971

数据来源: WILEY