摘要:

AbstractThe effect of secondary flows created by an internal spiral rib in an otherwise conventional smooth 2‐inch pipe on the transportability of “settling” suspensions of sand in water was investigated with emphasis on the effect of rib height.While the ribs were found to be a disadvantage at relatively high average mixture velocities because of increased pressure gradients, they were advantageous at low velocities. The deposit velocity and the pressure gradient at the deposit velocity in ribbed pipes of several pitch to diameter ratios and rib heights were correlated with respect to the corresponding smooth pipe values. These correlations are useful in pipeline design. The optimum rib geometry was estimated to be a pitch to diameter ratio of about 8 and a rib height in the range of 10–15% of the pipe diameter for the solid‐liquid mixtures inv

ISSN:0008-4034    

DOI:10.1002/cjce.5450540401

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

年代:1976

数据来源: WILEY

摘要:

AbstractWall mass transfer rates of dissolved oxygen have been measured in a vertical pipe, 5 cm. I.D., carrying aqueous slurries of 5, 10, and 15 vol%, 60–100 and 30–50 mesh sands at velocities in the range 1.2 to 3.35 m/s. The results show increases of up to 100% over those found with water, with the effect of the solids increasing with decreasing particle size and increasing with increasing concentration. The jDfactors decreased linearly with increasing Res, unlike the previous results with horizontal pipes where maxima were found relating to vertical concentration gradie

ISSN:0008-4034    

DOI:10.1002/cjce.5450540402

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

年代:1976

数据来源: WILEY

摘要:

AbstractSome beds contract and others expand when gas bubbles are introduced into the bottom of a liquid‐fluidized bed. A quantitative criterion for predicting which of these two events will occur in any particular case, derived in an earlier paper, is tested against experimental data from the literature and shown to predict all the observed trends with various process variables correctl

ISSN:0008-4034    

DOI:10.1002/cjce.5450540403

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe axial mixing of ion exchange resin and liquid in fluidized beds is modelled by a series of well‐mixed cells for the resin and an equal or larger number of mixed cells for the liquid. Concentration breakthrough curves are calculated using this mixing model, assuming finite mass transfer kinetics and irreversible equilibrium. The model is used to describe mixing patterns and kinetics in static fluidized beds (no resin flow); the information so obtained can be used to design continuous and periodic flow counter‐current fluidized bed ion exchange syst

ISSN:0008-4034    

DOI:10.1002/cjce.5450540404

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

年代:1976

数据来源: WILEY

摘要:

AbstractDrop/interface coalescence times measured at 293–343K are reported for three oil/water systems (benzene, paraffin oil and 1,1,2,2‐tetrabromoethane) with different interface ages. The anomalous coalescence behavior of water droplets is explained by considering the static electrical double‐layer residing at the interface which influences the film thinning and the film rupture processes.Analyses using simplified coalescence models reveal that the incorporation of temperature dependence on the physical properties such as density difference between phases, viscosity of the continuous medium and interfacial tension, does not produce satisfactory agreement with the measured coalescence times.The effect of mutual saturation in contrast to unsaturated systems on coalescence times is illustrated. The reproducibility of the drop/interface coalescence times is examined and explanations are offered, relating the method and the conditions of the experimentation.Finally the importance of both the coalescence time and the film thickness to drop stability analysis is demonst

ISSN:0008-4034    

DOI:10.1002/cjce.5450540405

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe Reynolds equation is extended to allow for the effects of shear and dilational surface viscosities on the axisymmetric drainage of planar films. It is shown that the number of immobile surfaces, n, may be expected to decrease with increasing film radius and bulk viscosity and with decreasing film thickness and surface viscosity, as observed experimentally. The predicted rate of film thinning agrees well with available experimental results.

ISSN:0008-4034    

DOI:10.1002/cjce.5450540406

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe work involved studying the potential of Na2SO4, NaCl, KCl, CaCl2and some eutectic mixtures of inorganic salt for storing thermal energy. Heat storage materials have wide application in devices such as “off‐peak” space heating furnaces. Data reveal Na2SO4to be a better heat storage material than other salts as well as conventional heat storage materials because of its dimorphic nature and high heat of transition. It is estimated that less than 0.29 m3of Na2SO4would be required for heating a normal sized house on the Canadian Pra

ISSN:0008-4034    

DOI:10.1002/cjce.5450540407

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe characterization of the evaporation rate of complex hydrocarbon mixtures, such as commercial oil fractions, under environmental conditions is discussed. It is shown that the relevant thermodynamic quantity is the total volume of vapour (per unit of initial oil mass) removed under isothermal differential distillation conditions (V m3/kg) as a function of the mass fraction of the oil remaining (F). Plots of F versus V for various isothermal conditions can be used to estimate evaporation rates since it is shown that V is equivalent to the group KsAsτs/Ms where Ksis the evaporation mass transfer coefficient (m/s), Asis the spill area (m2), τsis the evaporation time (s) and Msis the spill mass (kg). The basis of a methodology for estimating environmental evaporation rates is thus outlined. Methods of obtaining V versus F data are discussed, with calibrated wind tunnel evaporations being preferred. The estimation of evaporation rates under spreading and non‐isothermal conditions and the analogous dissolution process are discussed brie

ISSN:0008-4034    

DOI:10.1002/cjce.5450540408

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

年代:1976

数据来源: WILEY

摘要:

AbstractAn experimental investigation has been undertaken to determine the oxygen transfer rate of a rotating Couette flow oxygenator for low axial annular flow rates. The purpose of this study was to determine if such a device might provide a rational basis for the subsequent design of a blood oxygenator for respiratory support in clinical situations. Using oxygen and degassed water as an analog to oxygen and blood the Sherwood number was determined as a function of the axial Reynolds number and the Taylor number. Results show that oxygen transfer rates can be enhanced by at least ten times over that of the non‐rotating situation, the flow being laminar with vortex flow superposed. The present results were correlated as Sh vs. Ta/Tacover the range of parameters studie

ISSN:0008-4034    

DOI:10.1002/cjce.5450540409

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

年代:1976

数据来源: WILEY

摘要:

AbstractLocal mass transfer from a flat plate under the influence of an impinging laminar air jet, issuing from a square tube, has been studied using laser holographic interferometry. No angular variation in mass transfer was found to exist near the jet centre. However, in regions far from the jet centre a periodic angular variation in mass transfer was shown to exist. Regression equations for the local mass transfer coefficient are presented for Re = 710, 980, 1325 and 1810.

ISSN:0008-4034    

DOI:10.1002/cjce.5450540410

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

年代:1976

数据来源: WILEY