摘要:

AbstractCapital cost correlations are given for heat exchangers and furnaces. Correlations available in the literature and current data are compared on a consistent basis. Forty‐six graphs show the relative magnitude of the different correlations and the recommended correlation for each type of equipment is summarized in a table. Some data on the costs of installing heat exchange equipment are give

ISSN:0008-4034    

DOI:10.1002/cjce.5450540601

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

年代:1976

数据来源: WILEY

摘要:

AbstractVelocity profiles, turbulence intensities and Reynolds stresses were determined in pipes containing three helical ribs equally spaced on the pipe wall. Pitch to diameter ratios of 8 and 11 were used. The fluid considered was air and measurements were made with X wire probes calibrated for pitch and yaw effects.The ribs appeared to affect the axial flow via the tangential component which reached a maximum below the ribs in most cases. Evidence of increases in mixing length near the wall and decreases in the central core was obtained. These are in agreement with recent theoretical predictions of other workers. Turbulence intensities were not significantly altered when normalized with the usual friction velocity.

ISSN:0008-4034    

DOI:10.1002/cjce.5450540602

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

年代:1976

数据来源: WILEY

摘要:

AbstractTwo simple methods are presented for the characterization of inelastic power law fluids from falling sphere data. The methods involve the application of shear rate or shear stress correction factors which have been derived theoretically using Slattery's solution for creeping flow about spheres. Flow curves obtained using these methods are in excellent agreement with those measured on a Weissenberg rheogoniometer for 0.83 ≤ n ≤ 1.0.The experimentally determined drag coefficients are found to be in good agreement with the predictions of Slattery's creeping flow first approximation solution.The wall correction factors of Faxen and Francis appear to be valid for inelastic non‐Newtonian fluids up to a diameter ratio of at least

ISSN:0008-4034    

DOI:10.1002/cjce.5450540603

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

年代:1976

数据来源: WILEY

摘要:

AbstractNew correlations have been proposed for estimation of gas phase holdup, characteristic velocity, interfacial area for mass transfer and mean bubble size of bubble swarms under dispersed and fluidized operation of bubble columns employing single — and multi‐orifice distributors. The analysis of results include available literature data of other investigat

ISSN:0008-4034    

DOI:10.1002/cjce.5450540604

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

年代:1976

数据来源: WILEY

摘要:

AbstractPrevious theories which evaluated the stagnation depth of bubbles in a vertically oscillating liquid column are reviewed, and it is pointed out that they used an insufficient criterion for determining stagnation. The correct condition, which states that stagnation means zero mean velocity rather than acceleration, necessitates the solution of the equation of motion of the bubble, and thus viscous drag has to be included. It is shown, in accordance with available experimental data, that the value of the dimensionless group M = ω4A2ρh/2gPo(which gives the stagnation depth h) is not in general a constant, but is dependent on four other dimensionless groups. Although there is no reliable information concerning the drag coefficient curve for such a situation, it is suggested, on the basis of comparison between different drag coefficient curves, that the high values of M reported in the literature and not accounted for by theory are due to bubble shape deviations from sphericity in viscous flo

ISSN:0008-4034    

DOI:10.1002/cjce.5450540605

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe viscous and elastic properties of fluid interfaces play an important role in the stability of foams and emulsions as well as in the selection of surfactants for tertiary oil recovery. These properties were determined for aqueous solutions of surfactant, polymer, and polymer plus surfactant systems using a deep channel surface viscometer. The surface rheology of the adsorbed film was represented in terms of the two‐parameter Maxwell model. Depending on the system investigated, the films were found to be either viscoelastic, purely viscous, neither viscous nor elastic, or rigi

ISSN:0008-4034    

DOI:10.1002/cjce.5450540606

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

年代:1976

数据来源: WILEY

摘要:

AbstractThis paper presents results of an experimental investigation on the onset of longitudinal columnar vortices due to buoyant forces in the thermal entrance region of a horizontal parallel‐plate channel heated from below. Channels with width 30 cm and heights h = 2, 3 and 4.5 cm were employed in the experiment. The instability of the convective motion is caused by the effects of temperature gradients in both longitudinal and vertical directions and was observed by a direct flow‐visualization technique using smoke. Photographs of the front and top views of the vortex rolls are presented. Experimental results indicate that the wave number of vortex rolls remains constant along the flow direction and tends to approach the theoretical value as the channel width‐height ratio increases. It was also observed that the critical Rayleigh number from flow visualization is 1.4 to 10 times higher than the critical value from linear t

ISSN:0008-4034    

DOI:10.1002/cjce.5450540607

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe problem of low‐Peclet‐number thermal entry heat transfer for plane Poiseuille flow in parallel‐plate channels with uniform but unequal wall temperatures is approached by the eigenfunction expansion method utilizing the Gram‐Schmidt orthonormalization procedure. The formulation considers axial heat conduction and allows upstream heat penetration through the thermal entrance. Numerical results are obtained for the case with entrance condition parameter θ0= 1 and Peclet number Pe = 1, 5, 10 and 50. The effect of Peclet number on temperature distributions in both upstream and downstream regions is studied. At Pe = 50, the concept of thermal boundary layer is applicable and the present series solution does not yield physically reasonable temperature distribution locally near the upper plate at the thermal entrance. The difficulty may be attributed to the nature of thermal boundary conditions at the thermal entrance and the transition from elliptic problem to parabolic problem with the increase of Pecle

ISSN:0008-4034    

DOI:10.1002/cjce.5450540608

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

年代:1976

数据来源: WILEY

摘要:

AbstractRelative oscillatory motion between solid particles and a fluid increases the rate of interphase mass transfer due to the establishment of secondary flows (acoustic streaming). A critical survey of published data shows that mass transfer is well correlated by a theoretically founded dimensionless relation of the form\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar {N_{ah}} = K N_{Re}^{a}(A/D)^{b}N_{Sc}^{d} $$\end{document}where K, a, b and d depend on the Schmidt number. The equation successfully correlates experimental data for both gases and liquids over a range of frequencies F<1 Hz to F ∼ 106Hz, provided the amplitude to diameter ratio A/D is below 0.75. At higher values of this parameter,\documentclass{article}\pagestyle{empty}\begin{document}$ \bar N_{Sh} $\end{document}is better predicted by a quasi‐steady model which no longer depends on

ISSN:0008-4034    

DOI:10.1002/cjce.5450540609

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe batch neutralization of dilute hydrochloric acid by ammonia in a 10.16 cm i.d. bubble column has been examined. Experimental results agree with a diffusion‐type mixing model when 5.08 cm disc baffles are present, but agreement is only approximate with 7.62 cm diameter baffles. Axial dispersion coefficients have been determined and compared with published data. A simple batchwise procedure for evaluating bubble columns is suggeste

ISSN:0008-4034    

DOI:10.1002/cjce.5450540610

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

年代:1976

数据来源: WILEY