摘要:

AbstractIn a recently published paper(1), it has been demonstrated that the drag coefficient—Reynolds number relationship for a single spherical solid particle may be applied to multi‐particle systems as well, provided that modified definitions of the drag coefficient and Reynolds number incorporating suitable functions of the particles volume fraction are used.This generalised approach is now extended to include the case of a fluid dispersed phase. This done by incorporating a function of the ratio of the phase viscosities, based on theoretical derivations due to Hadamard—Rybczinski and Taylor in the modified definition of Reynolds number.All available experimental data (88 points from 3 sources, on 12 different liquid‐liquid systems) were recalculated and correlated on thi

ISSN:0008-4034    

DOI:10.1002/cjce.5450530501

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe effects of fluid viscosity, pipe length, radius and pressure wave celerity are examined by solving the equations of fluid motion numerically for impulsively started flows. Velocities are obtained in terms of axial and radial positions and time. Pressures are obtained as a function of axial position and time using an averaging process. The dimensionless group\documentclass{article}\pagestyle{empty}\begin{document}$\frac{{\rho a{\rm R}^2}}{{\mu {\rm L}}}$\end{document}is shown to determine the development of these profiles.At low values of this group, a significant axial variation in the velocity profiles occurs. The pressure fluctuations accompanying startup however are progressiveely more damped as this group decreases. Such fluctuations are shown theoretically and experimentally to disappear when the aforementioned group falls to about 1.6. The numerical method used is capable of being applied to other transient pipe flows.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530502

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

年代:1975

数据来源: WILEY

摘要:

AbstractUsing pulse‐input technique, axial dispersion coefficients were determined for polystyrene in tetrahydrofuran, in toluene and in a toluene/methanol mixture flowing in a long capillary tube under conditions such that the Reynolds number was less than 500. Low polydispersity polystyrene materials with nominal molecular weights ranging from 900 to 1.8 × 106were used. For the system studied and for fixed Reynolds numbers, the coefficient, on log‐log scales, was found to be a linear function of the product of the intrinsic viscosity and the molecular weight. An empirical equation relating this coefficient to the Reynolds number and to [η]M was obtained. This equation predicted results which agreed well with experimentally determined v

ISSN:0008-4034    

DOI:10.1002/cjce.5450530503

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

年代:1975

数据来源: WILEY

摘要:

AbstractFlotation rates of glass beads and of latex particles have been measured as a function of particle size using very small bubbles. With glass beads the observed rate versus size relationship agreed quite well with the prediction of a simple hydrodynamic collision model, but that found with latex particles did not. It is suggested that electrical forces may have to be taken into account when the particles have a significant zeta potential. With both types of particle, the relationship between flotation rates measured at two different bubble sizes is consistent with the model's predictions.

ISSN:0008-4034    

DOI:10.1002/cjce.5450530504

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe vaporization times of small (12 mg.) drops of a binary liquid on a flat plate were measured in the maximum (critical) heat flux region of boiling heat transfer. The binary system studied was water‐1‐pentanol, the mixture previously shown by other workers to exhibit the most pronounced concentration effect on critical heat flux. Evaporation curves are reported in the critical region for pure water, pure pentanol and a number of mixtures in the concentration range 1.0 to 2.5 weight % pentanol in water.It was confirmed that drop lifetimes can be obtained in the critical heat flux region by comparatively simple techniques and that there is a concentration effect on drop lifetime that is very similar to that observed during critical heat flux boiling studies. A minimum drop lifetime is observed at 1.8 weight % pentanol in water, the same concentration at which maximum critical heat fluxes were obtained in pool boiling studies at one atmosphere by S. J. D. Van Stralen and co‐wo

ISSN:0008-4034    

DOI:10.1002/cjce.5450530505

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

年代:1975

数据来源: WILEY

摘要:

AbstractAn experimental study of natural convection heat transfer conducted with water and thirteen aqueous polymer solutions obeying the power‐law model, varying in flow behavior index from 0.3 to 0.99, and consistency index between 10 and 5 × 103, showed that the behavior of these solutions justifies the theoretical treatment of this phenomenon proposed by Acrivos(10). The heat source was an internally electrically heated copper sphere, 5 inches in diameter, and designed to provide an isothermal surfa

ISSN:0008-4034    

DOI:10.1002/cjce.5450530506

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe effects of angle of cylinder orientation and cylinder length on mass transfer rates were studied for Reynolds numbers ranging from 6,000 to 18,000. Orientations (ϕ) varied from 0° to 90° for cylinders whose L/D's ranged from 5.26 to 21.04.The relation jm= m(N Re)nfit the data for a given orientation and L/D. Both jmand NNu, data compared favorably to literature values for transverse and parallel flow. Sherwood numbers were shown to be [1] a function of (N Re × sin ϕ) [2]to correlate with Consin's “cosine law” and [3] to be a function of L and ϕ.Peak mass transfer occurred between 45

ISSN:0008-4034    

DOI:10.1002/cjce.5450530507

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

年代:1975

数据来源: WILEY

摘要:

AbstractMechanical erosion from two crystalline coating materials, naphthalene and trans‐cinnamic acid, in submerged turbulent impinging jets of water has been studied. In the absence of diffusion, the observed erosion rates in the wall jet region vary linearly with wall shear stress. Threshold shear stress values below which erosion may be neglected have been defined for both coating materials. Erosion rates in the impingement region also depend on the shear stress which, depending on the crystalline grain size, may interact with pressure force

ISSN:0008-4034    

DOI:10.1002/cjce.5450530508

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe theory of gas absorption with chemical reaction was used to obtain values of effective interfacial area,a, liquid‐side mass‐transfer coefficient,kLa, and gas‐side mass transfer coefficient,kGa, in a venturi scrubber for the Wet‐Approach mode of operation. Some data were also obtained for the Pease‐Anthony mode of operation in order to make a rational comparison between the two modes of operation. The hydrodynamic characteristics of the venturi scrubber were studied for the two modes of operation over a wide range of gas and liquid flow rates. Further, the effect of the viscosity of the liquid and the surface tension on effective interfacial area was inv

ISSN:0008-4034    

DOI:10.1002/cjce.5450530509

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe damped turbulence model has been applied to the problem of absorption with a first order chemical reaction through a gas‐liquid interface into a turbulently flowing liquid. An analytical solution has been obtained in terms of Gauss hypergeometric functions. A further investigation has shown that the solution is fairly insensitive to the boundary condition inside the liquid phase. A simpler solution has also been obtained with a negligible loss of accurac

ISSN:0008-4034    

DOI:10.1002/cjce.5450530510

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

年代:1975

数据来源: WILEY