摘要:

AbstractThe dispersing action of a mass of slowly moving fluid is modelled by a stochastic partial differential equation. The separate components of the fluid velocity are represented as stochastic processes and appear as coefficients in that equation. These processes can take one of two forms: Markov processes with finite state‐space, or independent Ornstein‐Uhlenbeck processes.To confirm the predictions of the model they were compared with the mean response to a pulse‐like injection of tracer and with the observed cross‐correlation between tracer concentration at two points in the fluid. The statistical properties of the velocity processes, as estimated from these tracer studies, were confirmed by direct measurement with a hot‐film anemome

ISSN:0008-4034    

DOI:10.1002/cjce.5450500102

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

年代:1972

数据来源: WILEY

摘要:

AbstractA formulation is developed for the flow of an incompressible fluid through a two dimensional packed bed having a spatially variable void fraction, through the statement of the Ergun Equation in a two dimensional system.Computed results are presented for particular spatially distributed void fractions in the bed, which indicate that a lateral variation in the resistance to flow may cause appreciable flow maldistribution and “cross flow” effects.This work is thought to be a first, necessary step in the quantitative understanding of channeling and by‐pass phenomena in packed bed rea

ISSN:0008-4034    

DOI:10.1002/cjce.5450500103

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

年代:1972

数据来源: WILEY

摘要:

AbstractVelocity profiles were measured in a stirred tank with a turbine impeller using a three‐dimensional, pitot tube probe. A tangential jet model was used to describe the flow in the region of the impeller, and two‐dimensional potential flow models and a circular jet were used to describe the flow in the rest of the tank. The tangential jet model accurately predicted the measurements from this work and comparable measurements reported in the literature for water and air, for varying impeller diameter and speeds and for different tank diameters. In the rest of the tank a three‐dimensional, low velocity, flow field exists; and the center of circulation is not a true stagnation point. The flow at this point is tangential. The two‐dimensional models only qualitatively described the flow in this region, and a three‐dimensional model would be required. It was experimentally and theoretically confirmed that standard practice of using 10% baffles effectively controls the flow in

ISSN:0008-4034    

DOI:10.1002/cjce.5450500104

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

年代:1972

数据来源: WILEY

摘要:

AbstractIn the first part of the work, the authors have experimentally studied the fall rate of single drops of chlorobenzene with different diameters into a water column subjected to strictly sinusoidal pulsations. It has been shown that there is always a retarding effect and that, in certain cases, the average speed in a pulsated medium may be much lower than the one measured in a motionless medium.In the second part of the work, the authors have made a theoretical analysis of the motion of a drop in a pulsated medium. An equation is suggested for describing that motion, which results from the analysis of the forces in which the drag coefficient is modified in order to take into account the dynamic effects. The aforesaid equation has been systematically solved by means of analog and digital computers and the results, which have been compared with the experimental data, agreed very well with the latter, the deviation being less than 1.18%.

ISSN:0008-4034    

DOI:10.1002/cjce.5450500105

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

年代:1972

数据来源: WILEY

摘要:

AbstractEntry lengths and contraction losses have been determined for 0.01, 0.2 and 0.6% aqueous solutions of Separan AP‐30. The Reynolds numbers ranged between 102and 105in 1/2‐in. and 2‐in. tubes. At Reynolds numbers in excess of 2100, the entry lengths and contraction losses for the polymer solutions are significantly larger than those for Newtonian fluids. These effects are shown to be related to the transitional flow phenomena which occur with drag reducing polymer solutions.At low Reynolds number the contraction loss data show expected trends but are in quantitative disagreement with predictions based on recent studies in capillary tubes. These indicate that the analyses based on small tubes are less general than antici

ISSN:0008-4034    

DOI:10.1002/cjce.5450500106

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

年代:1972

数据来源: WILEY

摘要:

AbstractTerminal velocities of drops of organic liquids of diameter 0.0726 to 0.7256 cm in polymer solutions are determined. The Reynolds number range covered is 0.1 to 103. Visual observations on the shapes and oscillations of drops are reported. A correlation for the terminal velocity data is presented.

ISSN:0008-4034    

DOI:10.1002/cjce.5450500107

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

年代:1972

数据来源: WILEY

摘要:

AbstractDrop volume studies were made by forming non‐Newtonian pseudoplastic drops in a continuous toluene phase and chlorobenzene drops in non‐Newtonian continuous phases. Combination of results for these cases enabled development of a correlation for the prediction of non‐Newtonian drop volume in a non‐Newtonian continuous phase. The development is confined to power law fluids and provides expressions for both long and short nozzles in terms of a two‐stage drop formation process. Variables included nozzle size, formation time, and rheological properties from eight non‐Newtonian systems in a program

ISSN:0008-4034    

DOI:10.1002/cjce.5450500108

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

年代:1972

数据来源: WILEY

摘要:

AbstractAn experimental study of heat transfer from a horizontal tube to a fluidized bed was carried out in the presence of nearby unheated tubes. The effect of the number of tubes, their size, configuration, and the type of fluidized materials was studied. Certain configurations caused as much as a 56% reduction in heat transfer over the most favorable case. The top of the tube was covered by stagnant solids, the bottom partially by a gas film, and the sides by a small region of vigorously agitated solids. Most of the heat transfer occurred in the side region. An overall heat transfer coefficient of 35 Btu/hr‐ft2‐°F. was found at the best condit

ISSN:0008-4034    

DOI:10.1002/cjce.5450500109

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

年代:1972

数据来源: WILEY

摘要:

AbstractGases covering a wide solubility range were used to measure absorption rates from single bubbles rising freely in water. Absorption rates were not sensitive to any power of the diffusion coefficient and solubility alone proved to be an adequate correlating parameter.Experiments with bubbles containing inert and soluble gas mixtures yielded no evidence for a gas‐film resistance, confirming published theory.Results for the absorption of CO2by NaOH solutions correlated well with the theory for pseudo‐first‐order fast reactions, provided allowance was made for a decreasing “physical” solubility of CO2with increasing ionic strength of the

ISSN:0008-4034    

DOI:10.1002/cjce.5450500110

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

年代:1972

数据来源: WILEY

摘要:

AbstractA mechanism for grinding disperse dyes in a sand mill is discussed which is supported by experimental data. Experimental data with disk, cylinder and vibrator agitators are examined from the point of view of dimensional analysis. All rotors exhibited fluid slip and decreased efficiencies at high rotor speeds. Cylinder rotors provided higher rates of energy input to the milling paste, and shorter grinding times, relative to disk and vibrator agitators.

ISSN:0008-4034    

DOI:10.1002/cjce.5450500111

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

年代:1972

数据来源: WILEY