摘要:

AbstractThis paper presents the results of an experimental study on the gas holdup and the liquid phase axial dispersion coefficient in a narrow packed and unpacked rectangular bubble column. In both cases the gas and liquid flow rates were varied and the data were obtained by employing standard tracer technique. The gas holdup and the axial dispersion coefficient for both the packed and unpacked columns were found to be dependent on the gas and liquid flow rates. For given gas and liquid velocities and a given packing size in the case of the packed column, the rectangular column gave significantly higher dispersion coefficients than a cylindrical column of the equivalent cross sectional area. This result agrees very well with the one predicted by the velocity distribution model. The correlations for the Peclet number, the axial dispersion coefficient, and the fluid holdup for both the unpacked and packed bubble columns are presented.

ISSN:0008-4034    

DOI:10.1002/cjce.5450550102

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

年代:1977

数据来源: WILEY

摘要:

AbstractAn air bubble that passes through a horizontal interface from a lower layer of Freon‐113 to an upper layer of aqueous glycerol forms a two‐phase bubble in the upper layer as a result of entrainment of a certain volume of Freon‐113 from the lower layer. The volume of entrained Freon‐113 and the rise velocity of such a two‐phase bubble have been measured. The former increases with an increase of the bubble size irrespective of the viscosity of the upper liquid. The latter is somewhat lower than that of a normal air bubble of the

ISSN:0008-4034    

DOI:10.1002/cjce.5450550103

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

年代:1977

数据来源: WILEY

摘要:

AbstractInterfacial areas were determined for gas‐liquid systems in a column with transparent walls by the chemical and two physical methods: photography and light attenuation. The advantages of the different methods are discussed and improvements in the physical methods are described. By using a Data Tablet Digitizer, the photographic technique provides additional information on the gas dispersion without increasing the amount of work needed for analysis of the photographs. Use of the light attenuation technique is extended to conditions when multiple scattering and stray light must be taken into account; it can then be used up to values of optical path densities equal to 8

ISSN:0008-4034    

DOI:10.1002/cjce.5450550104

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe formation of ring vortices under water has been studied at orifices of diameter 2.54 to 6.35 cm and formation times from 0.04 to 0.68 s, with orifice Reynolds number between 3 × 104and 3 × 105. Ciné photographs of the formation process were taken, and the initial velocity of the vortices was found in general to be one half of the velocity of flow through the orifice. The translational momentum of the vortex rings was measured by a surge‐tube method. It was concluded that the formation process is most efficient when the length of the impulsive jet is not more than two orifice diame

ISSN:0008-4034    

DOI:10.1002/cjce.5450550105

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe equations of motion and energy for Newtonian fully developed fluid flow in an internally finned helical coil were solved numerically for the case of uniform heat flux with peripherally uniform temperature for low Reynolds numbers. Plots for the axial velocity, secondary stream function and fluid temperature are given. For a given fin geometry, it was found that fRe is both a function of Dean number and radius of curvature, whereas the average Nusselt number is a function of Dean number only. For a given fluid at a constant pressure drop, a finned coil gave lower values for the average Nusselt number than a finless tube with the same inside diameter and radius of curvature.

ISSN:0008-4034    

DOI:10.1002/cjce.5450550106

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

年代:1977

数据来源: WILEY

摘要:

AbstractFlow boiling and saturated pool trailing were studied in water, and in ethylene glycol and aqueous antifreeze solutions. Boiling took place from an electrically heated cast iron surface at pressures close to atmospheric. In the flow boiling tests, velocities and subcoolings were varied up to 3 m/s and 36°C respectively, and effects of changes in flow passage geometry were examined. In 50 weight percent antifreeze mixtures the pool boiling critical heat flux increased relative to pure ethylene glycol in aqueous solution. Both critical heat flux and heat transfer coefficients decreased as percent water in the mixtures tested was reduced

ISSN:0008-4034    

DOI:10.1002/cjce.5450550107

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

年代:1977

数据来源: WILEY

摘要:

AbstractAn unsteady, three dimensional diffusion equation has been solved for the dispersion of pollutants, with or without chemical reaction, from an instantaneous point source in a semi‐bounded water under the influence of a vertical shear.The solution, which has been shown to be valid for two limiting cases: unbounded waters and large diffusion time, shows that the concentration ellipsoids would elongate themselves under the influence of a vertical shear, although the degree of elongation would also depend on diffusion coefficient and diffusion time. The effect of chemical reactions is to reduce the concentration level around the moving center of mass. The boundary affects profoundly the concentration distribution when the source is close to the shor

ISSN:0008-4034    

DOI:10.1002/cjce.5450550108

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

年代:1977

数据来源: WILEY

摘要:

AbstractA transient analysis of a fluid‐solid pyrolysis system in which a solid is pytolyzed to form a fluid product and a solid product is presented. The analysis, based on utilization of the so‐called volume reaction model, takes into account the simultaneous heat and mass transfer phenomena in the particle being pyrolyzed. Variations of physical parameters with respect to temperature and/or solid concentration are not neglected. Effects of the Lewis number on the solid conversion, the fluid and solid concentration distributions, and the temperature profile in the particle are examined. The results are graphically presented and interpre

ISSN:0008-4034    

DOI:10.1002/cjce.5450550109

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

年代:1977

数据来源: WILEY

摘要:

AbstractCorrosion of out‐core piping in the primary circuit of nuclear power reactors adds both dissolved and particulate metals and their oxides to the water coolant. The particles deposit on the fuel sheaths and pressure tubes in the reactor core and are irradiated there while they dissolve in the heated water. Transport of now‐radioactive solute around the circuit makes the out‐core surfaces radioactive, which increases radiation exposure to operators and maintainers.A mathematical model has been developed to describe these processes of deposition, irradiation and release of corrosion products on the fuel bundles and pressure tubes of CANDU pressurized water reactors. The model's predictions compare well with data from in‐reactor loop fuel, and data from fuel and pressure tubes from Pickering Generating Station. The model suggests ways to control the growth of out‐core radiation fields and keep them at the current low levels of Pickering. Hot filtration of the reactor water and an increase in water pH are two solutions analyzed with

ISSN:0008-4034    

DOI:10.1002/cjce.5450550110

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

年代:1977

数据来源: WILEY

摘要:

AbstractA new apparatus is proposed which allows the fractionation of protein mixtures by convective electrophoresis. The cell is arranged as a stack of elementary units, each of which consists of two compartments bounded by semi‐permeable membranes and separated by a permeable cotton diaphragm. The solutions are circulated by forced convection, either co‐current or eounter‐current. The development of transport equations has made it possible to define which parameters control separation. An experimental study has been carried out to show the effect of these parameters (potential difference, rate of convection, number of elementary units) on the concentration of proteins from dilute solutions and on the fractionation of binary mixtures. Finally, predictive calculations are attempted in order to define the optimum operating conditions, and in order to scale‐up the apparat

ISSN:0008-4034    

DOI:10.1002/cjce.5450550111

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

年代:1977

数据来源: WILEY