摘要:

AbstractDrag reduction in turbulent pipe flow by means of boundary and centerline injection of long hair‐like asbestos fibers has been investigated. Pressure drop and mean velocity profiles were measured at various Reynolds numbers and injection rates in order to study some mechanistic aspects of drag reduction in water‐fiber and polymer‐fiber systems. Drag reduction in a water‐fiber system is attributed to a decrease in the momentum transfer in the turbulent‐core region, whereas synergism has been found to be a wall p

ISSN:0008-4034    

DOI:10.1002/cjce.5450590101

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

年代:1981

数据来源: WILEY

摘要:

AbstractA study of the air flow characteristics is reported for a vortex chamber 122 cm in diameter consisting of an upper cylindrical section 61 cm high and of a lower conical section 108 cm high. Measurements were made with a five‐channel pressure probe of the radial profiles of tangential and axial velocities, with varying inlet air velocity and axial distance from the top of the chamber. Measurements of the static pressure profiles were made simultaneously. Finally, the angle of flow of the air entering through the single tangential inlet could be adjusted, and its effects on the flow recorded.From these results and from a theoretical analysis, generalized expressions for the tangential velocity profiles were obtained for the two regions of flow, forced‐vortex and quasi‐free vortex, which prevail in a confined vortex chamber, as a function of the entrance air velocity and of the radius at the point considered only. The angle of entering air was found to have no effect on the tangential velocity and only a minor effect on the static pressure distribution. The outlet diameter of the chamber was found to have a large effect on the profile of the axial velocities, reflecting the influence of the chamber static pressure on the l

ISSN:0008-4034    

DOI:10.1002/cjce.5450590102

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

年代:1981

数据来源: WILEY

摘要:

AbstractA study, both analytical and experimental, has been made on the natural convection induced by an isothermal vertical plate immersed in a large volume of water at a temperature which was close to its freezing point. A particular attention has been paid to the effects resulting from the non‐linearity existing between the density of water and its temperature. when the latter was close to 4°C. The plate temperature (Tw) was in the range from 8.0°C to 27.2°C. while the water temperature (Ti) varied between 0°C and 22.2°C. The Prandtl numbers for the flow were in the range from 6.4 to 13.7. An excellent agreement between the theoretical solution and the experimental data has been ob

ISSN:0008-4034    

DOI:10.1002/cjce.5450590103

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

年代:1981

数据来源: WILEY

摘要:

AbstractExperimental data are reported on velocities of entrainment in liquid fluidized beds. Single as well as multicomponent mixtures of solids varying in size and/or density have been investigated. By drawing an analogy with partially fluidized bed systems, phase equilibrium diagrams of binary and ternary mixtures have been constructed and presented. Correlations have been developed for the prediction of velocities related to the beginning of entrainment, minimum entrainment and complete entrainment.

ISSN:0008-4034    

DOI:10.1002/cjce.5450590104

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn a recent article(1), it has been postulated that the air‐lift principle may be applied to the raising of liquids or suspensions possessing shear‐thinning Theological behaviour, in order that significant reductions in power requirement may be made compared with conventional mechanical pumping. Using a 41 mm i.d. riser, an experimental study of the raising of highly flocculated kaolin suspensions, at volumetric concentrations ranging from 8.1 to 18.4%, has confirmed that power savings are possible, provided that the isothermal efficiency of the compressor for air injection is substantially greater than mechanical pump efficiencies. Such power savings appear limited to a range of superficial air velocity in the air‐lift riser of 0.25 to 1.25 m.s.−1, and to suspensions containing a relatively high volumetric fraction of flocculated

ISSN:0008-4034    

DOI:10.1002/cjce.5450590105

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe electrochemical oxidation of phenol for waste water treatment applications was investigated on lead dioxide packed‐bed anodes. Cells were operated in both batch and continuous modes with feed streams up to 1100 nig/1 phenol dissolved in aqueous solutions of Na2SO4and H2SO4or NaOH. All the phenol in solution could be readily oxidized but complete total organic carbon (T.O.C.) removal was more difficult. The percent phenol oxidized increased with increasing current density, and decreased as initial phenol concentration, electrolyte flow rate, pH and anode particle size were increased. Results are compared to simple mathematical model

ISSN:0008-4034    

DOI:10.1002/cjce.5450590106

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

年代:1981

数据来源: WILEY

摘要:

AbstractBased on the results of an earlier paper, a model is developed to include the homogeneous reaction in the external boundary layer. It is assumed, consistent with those results, that there is no homogeneous reaction within the particle. A feasibility region is constructed using limiting cases along the lines described there. Under some conditions, the model predicted up to five steady states for a given set of ambient conditions. For large particles, a flame develops in the boundary layer and the main product is CO2. Under such conditions, the reaction locus coincides with the double film model. While for small particles, no flame develops and the major product is CO. The solution is sensitive to the type of radiative interaction which obtains. The combustion rate increases with increase in particle temperature until a certain point, then decreases with further increase in temperature, and eventually turns back and increases again. Such behavior has been observed in some rate measurement experiments.

ISSN:0008-4034    

DOI:10.1002/cjce.5450590107

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

年代:1981

数据来源: WILEY

摘要:

AbstractFluid bed retorting of oil sands is a viable method of extracting oil from mined oil sands. The process is based on a direct heating concept in which one vessel is utilized for the pyrolysis and vaporization of the bitumen contained in the oil sand and for the burning of the residuals which remain with the sand.Experimental results show that a significantly upgraded liquid hydrocarbon product can be obtained. Oil yields can exceed eighty per cent of the bitumen present in the feed material. The sulfur content of the produced oil is reduced. Gas produced can have a significant heating value and contains sulfur mainly in the form of hydrogen sulfide. Refluxing of the overhead product increases liquid yields and reduces the sulfur content of the oil. Water injection and the use of enriched air has a beneficial effect on the process. Thermal efficiencies in excess of eighty per cent can be achieved without recovering the heat from the expended sand.

ISSN:0008-4034    

DOI:10.1002/cjce.5450590108

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

年代:1981

数据来源: WILEY

摘要:

AbstractFor molten polymers, each theological property provides a different basis for comparison and characterization. This point is illustrated by reference to the results of an extensive testing program involving a series of four commercial blow molding resins, each produced by a different Canadian manufacturer. Three high density polyethylenes were studied at 170°C, while a polypropylene was studied at 190°C. Properties measured included viscosity, first normal stress difference, dynamic viscosity, storage modulus, extrudate swell as a function of time and shear rate, and stress growth functions for both shear and uniaxial elongatio

ISSN:0008-4034    

DOI:10.1002/cjce.5450590109

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe adsorption isotherms of the three main types of surfactant have been plotted against various pH's and temperatures. It has thus been possible to propose new ways of insuring adsorption and determining the importance of the ionic links and hydrophobic interactions involved in the various‐medium conditions considered. The presentations by Lauginuir and Freundlich have permitted to develop the adsorption equations corresponding to each case. Finally, the isotherm plotting in a series of low concentrations has permitted to predict the maximum volume of an effluent purified per kilogram of substrate, in the case of the concentrations frequently found in the waste water

ISSN:0008-4034    

DOI:10.1002/cjce.5450590110

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

年代:1981

数据来源: WILEY