ISSN:0001-1541    

DOI:10.1002/aic.690040224

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690040225

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690040202

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractNearly 900 values of local heat transfer coefficients were correlated for water flowing through long annuli 1/8, 1/4, and 3/8 in. wide, electrically heated at their inner surfaces and containing three spacer ribs. Both cosine and uniform lengthwise heat‐flux distributions were employed. All heat transfer coefficients were computed for positions corresponding to (L/De) ratios larger than 150. Several methods of correlation were attempted and compared, especially with respect to the method of evaluating physical properties. The proportionality of the Colburnjfactor to the Prandtl and Reynolds numbers with their usual exponents was verified, and the dependence ofjuponD2/D1was analyzed. There was no significant effect of cosine heat‐flux distribution on the heat transfer coefficients. Evaluating physical properties at the usual film temperature gave the best correlation. A simplified dimensional equation for water at moderate temperatures and pressures was also develo

ISSN:0001-1541    

DOI:10.1002/aic.690040203

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractAn equivalent Poiseuille's Law is derived for a homogeneous isotropic turbulent field. The derivation is based on an analogy between momentum transfer and heat and mass transfer, three coefficients being used to characterize the exchange process: (1) the molecular viscosity µ, (2) an intensity parameter to characterize the magnitude of the turbulent velocity fluctuationsν2, and (3) a scale parameter to characterize the scale of the turbulence

ISSN:0001-1541    

DOI:10.1002/aic.690040204

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractA corresponding‐states correlation of low‐density binary‐ and self‐diffusion coefficients is presented. The equations are simple to use, are sufficiently accurate for most calculations, and correlate those data used in their derivation somewhat better than calculations based on the Lennard‐Jones potential if potential parameters have to be estimated from the critical properties. The Enskog kinetic theory of dense gases is used in modified form to obtain an expression for the high‐density diffusion coefficient for isotopic mixtures in terms of the viscosity and compressibility of the gas. Generalized viscosity and compressibility charts are then used to construct a graph for predicting a reduced self‐diffusion coefficient as a function of reduced temperatureTr=T/Tcand reduced pressurepr=p/pc. The effect of the pressure on the Schmidt number, Sc = μ/ρ

ISSN:0001-1541    

DOI:10.1002/aic.690040205

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractIn this study a radioactive tracer technique was used to determine the kinetic reaction rate constants in the CO2NaHCO3Na2CO3H2O system at temperatures of 32, 50, and 68°F., and at various values ofpH ranging from 5.6 to 7.6. By operating with this system at chemical equilibrium but at isotopic disequilibrium, it was possible to divorce the influence of the diffusion of CO2into and out of the aqueous solution from the kinetic effects of the chemical reaction. Radioactive carbon‐14 in the form of CO2was analyzed by means of the Bernstein‐Ballentine technique in order to measure the rates of reaction.By this treatment, without using intricate equipment, reaction rate constants were computed from simple, integrated first‐order equations. Results showed that values for the forward rate constant of the reaction CO2+ H2O ⇌ HCO3−+ H+agreed well with the values published by previous investigators. On the other hand, the forward rate constants of the reaction CO2+ OH−⇌ HCO3−were about 100 times as large as previously reported values. This difference is believed due to the complete elimination of any mass transfer effects in this study. In addition, values for the rate constants of the reverse reactions were measured for the first time, and the calculated values of the equilibrium constants for the two reactions agreed within 6% on the average with those given by Harned and Owen. The technique used, with its variations, is expected to have numerous applications in the study of the kinetics of

ISSN:0001-1541    

DOI:10.1002/aic.690040206

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractMeasurements were made of the rate of fall of drops of five organic liquids through an aqueous phase contained in eight vertical cylinders of various diameters. Newton's equation for the wall proximity effect for rigid spheres or cylinders predicts values somewhat in excess of the observed. A correction factor equation with the more convenient equivalent spherical diameter is presented. Its use is limited tod/Dratios less than one half. The ultimate velocity of a drop of specific size in an infinite medium can be calculated from that measured in a small tube by multiplying the latter by the ratio of the tube cross‐sectional area to the area of the annular space between tube wall and dro

ISSN:0001-1541    

DOI:10.1002/aic.690040207

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

摘要:

AbstractEquations were derived by Nusselt for condensation on a vertical bank of horizontal tubes employing several questionable assumptions. His theoretical results indicate that the average condensing coefficient for a tube in ann‐tube vertical bank should ben−1/4times the single‐tube coefficient. An empirical modification for turbulence previously suggested by the present author changed the factor ton−1/6. To facilitate further experimental studies and design calculations, precise equations are developed for condensate loading for the different common tube layouts bounded by a circle. These equations use a generalized factorn−1/swhere a value of s/4>1.0 becomes an index of t

ISSN:0001-1541    

DOI:10.1002/aic.690040208

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690040209

出版商:American Institute of Chemical Engineers    

年代:1958

数据来源: WILEY