ISSN:0001-1541    

DOI:10.1002/aic.690070102

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractViscous fluids are frequently agitated by multiple impellers and in vessels only slightly larger than the impeller. This paper presents data for both Newtonian and non‐Newtonian fluids agitated under such conditions. The large decreases in power requirements (at a given level of mixing rate in the non‐Newtonian system) which are possible by use of low tank diameter, impeller diameter ratios and/or two impellers, have been quantitatively studied.The types of impellers used in the non‐Newtonian work and the ranges of conditions over which power requirement correlations were developed are summarized as follows:TextDT/DnNReMarine propeller0.42‐1.01.4 ‐4.80.16‐1.00.67‐1320Fan turbine0.33‐0.671.3 ‐3.00.21‐1.46.6 ‐160Flat‐Bladed turbine: one impeller0.17‐0.671.3 ‐5.50.20‐1.52.0 ‐1800two impellers per shaft0.33‐1.001.023‐3.50.14‐1.000.15‐620The results generally confirm an approach developed earlier, for the broader ranges of variables listed above. For the non‐Newtonian fluids of primary interest in this study, that is purely viscous materials having flow behavior indexes of less than unity (pseudoplastics, Bingham plastics), the prediction of power requirements has been developed to nearly the same le

ISSN:0001-1541    

DOI:10.1002/aic.690070103

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690070143

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractRates of diffusion of helium, nitrogen, and carbon dioxide through alumina pellets were measured at atmospheric pressure and room temperature. The cylindrical pellets, ¾ in. diameter and ⅜ in. in length, were prepared from α‐alumina particles with a mean pore radius of 65 Å. Surface area and pore volume data indicated that the corresponding mean pore radius of the micro and macropores in the whole pellet was 96 Å.The results showed that Knudsen type of diffusion was the controlling transport process despite the large fraction of void volume in the macropores. Carbon dioxide diffused more rapidly than expected, suggesting the possibility of migration of physically adsorbed molecules along the pore walls.The diffusion rates were about 16% higher than predicted, with a mean pore radius (Wheeler model) based upon the void volume of both micro and macropores used. However there is no logical basis for using this mean pore radius for a pellet having widely separated, micro and macropore size distri

ISSN:0001-1541    

DOI:10.1002/aic.690070104

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractThe phase‐equilibria data of the propane‐hydrogen sulfide system has been previously investigated from 32°F. to the critical locus. Since this represents about one‐half of the phase data, the primary purposes of the present study were to complete the data to the solid‐liquid‐vapor region which starts about —125°F. and to verify the results of other investigators at the higher temperatures.Five mixtures of propane‐hydrogen sulfide were studied, ranging from 8.6 to 78.3% propane, with the dew‐ and bubble‐point method. A temperature‐composition diagram for six isobars from 400 to 20 lb./sq. in. abs. presents most of the essential data. Vaporization equilibrium constants are tabulated together with thex‐ydata for these isobars. The data of Kay and Rambosek (3) and Steckel (4) were verified to within 2% except near the vicinity of the azeotrope.A new method was used to fix the temperature of the azeotrope for two of the five mixtures and a sixth mixture. The determination of the azeotropic temperatures was made by a graphical method in which the differences between the dew‐ and the bubble‐point pressures for each mixture were plotted against the temperature. The minimum value of the curve corresponds to the temperature of the azeotrope. The application of this method to the data of Kay and Rambosek (3) gave results which were in agreement with this study, while the original results by these authors as determined by an indirect method were in poor agreement.A measure of the reliability of the composition, temperature, and pressure data of the solid‐liquid‐vapor region was indicated when checks within 5% were found with Da

ISSN:0001-1541    

DOI:10.1002/aic.690070105

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractThe problem of defining an average diffusion coefficient of a gas arises in the application of the film resistance model for mass transfer to systems involving multicomponent mixtures of simultaneously diffusing gases and in the application of mass, momentum, and heat transfer analogies in such systems. It is shown that, in some cases, integration of the diffusion equation with an average value of the diffusion coefficient will not be valid. An approximate solution of the diffusion equation is obtained with the concentration dependence of the diffusion coefficient taken into account. Some numerical examples are constructed for comparison of this method and several methods for defining an average diffusion coefficient with an exact solution of the Stefan‐Maxwell relation

ISSN:0001-1541    

DOI:10.1002/aic.690070106

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractDrag coefficients were determined at low Reynolds numbers for cylinders (0.1 ⩽Re⩽ 1.0) and flat plates (0.05 ⩽Re⩽ 2.0) moving through a viscous medium. The drag coefficient was calculated from the force required to move the immersed body through the fluid, and preliminary work on spheres was used to calibrate the apparatus. For all bodies studied the drag coefficient was inversely proportional to the Reynolds number. The data were analyzed by a least‐squares method to obtain the relationship between drag coefficient and Reynolds number.The diameter of the tank containing the viscous fluid had a very definite effect upon the drag coefficient of the various cylinders and flat plates studied. In the range ofDT/D(tank diameter/cylinder diameter) studied the relationships recommended by White involving the wall effect and the end correction agree with experimental data for values ofL/D(cylinder length/cylinder diameter) greater than 16. AtL/Dratios less than this drag coefficients are lower than those predicted by White's equations, and the experimental curves are recommended for these ratios.For flat plates in perpendicular flow no effect of theW/L(plate width/plate length) was detected in the range studied. The tank diameter however had a considerable effect, and a curve is proposed to predict drag coefficients for flat plates in perpendicular flow in the range of experimental condition

ISSN:0001-1541    

DOI:10.1002/aic.690070107

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractThis study deals with boundary‐layer flow on continuous solid surfaces. Flow of this type represents a new class of boundary‐layer problems, with solutions substantially different from those for boundary‐layer flow on surfaces of finite length. In this paper the boundary‐layer behavior on continuous surfaces is examined, and the basic differential and integral momentum equations of boundary‐layer theory are derived for such surfaces. In subsequent papers these equations will be solved for the boundary layer on a moving continuous flat surface and a moving continuous cylindrical surface, for both laminar and turbulent flow in the bound

ISSN:0001-1541    

DOI:10.1002/aic.690070108

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractExperimental heat transfer studies were carried out in beds of unconsolidated glass beads and sand through which fluids were flowing. The scope of the measurements included four fluids, helium, air, carbon dioxide, and water liquid at atmospheric pressure in beds packed with four sizes of glass beads, 110, 370, 570, and 1,020 μ and with two sizes of sand, 110 and 240 μ. Flow rates ranged form 1 to 26 lb./(hr. sq.ft.) in a direction parallel and countercurrent to energy flow.The data were interpreted in terms of apparent, effective thermal conductivities of the bed. The values ofkeincrease significantly with mass velocity of fluid.By considering the mechanism of heat transfer in porous media a relationship was developed betweenkeand the heat transfer coefficient between fluid and particle. Treatment of the experimental data in this fashion, combined with available information for larger particles, results in a correlation of Nusselt and Reynolds numbers for air that covers the rangeN Re m= 10−

ISSN:0001-1541    

DOI:10.1002/aic.690070109

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY

摘要:

AbstractThe influence of the concentration gradient on the density gradient in a thermal‐diffusion column is called theforgotten effect. A modification of the theory developed by Furry, Jones, and Onsager is proposed to include the effect of the horizontal concentration gradient. A sample calculation with the system toluene‐cyclohexane shows that the equations predict the proper behavior for a forgotten‐effect s

ISSN:0001-1541    

DOI:10.1002/aic.690070110

出版商:American Institute of Chemical Engineers    

年代:1961

数据来源: WILEY