摘要:

AbstractAn experimental investigation of the combined natural and forced convective effects was carried out which involved the measurement of the rate of evaporation of water from porous stationary spheres (1/4, 3/8 and 1/2‐in. in diameter) under steady conditions in an electrically‐heated stainless steel chamber. The spheres were suspended in a stream of super‐heated steam at atmospheres ranging from 50 to 1000°K. Both the opposing and aiding flow cases were investigated. The Reynolds number varied from 0 to 1489 and the turbulence intensity was less than 1%. The parameter [(Gr)/(Re2)] was found to be of fundamental importance in correlating the results. The rates of heat transfer in the mixed flow region for the opposing flow case was higher than for aiding flow. The transition between the two mechanisms was found to be gradual but very complex in the case of opposin

ISSN:0008-4034    

DOI:10.1002/cjce.5450450401

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

年代:1967

数据来源: WILEY

摘要:

AbstractMass transfer coefficients were determined for 1/8 inch diameter spherical particles suspended in stirred aqueous iodine solutions. Particle density was adjusted to within 5% of the liquid density. For these particles, suspended in a covered and fully baffled vessel, the effect of impeller speed (200‐600 rpm), system Schmidt number (770‐11, 300) and impeller type (fan disk turbine, propeller and 45° paddle and turbine) on the mass transfer coefficient, was examined.A dimensionless group correlation using the impeller blade tip velocity represent the data with an average deviation of 8% and a maximum deviation of 27%.Nsh= 2 + 0.109\documentclass{article}\pagestyle{empty}\begin{document}$$ N_{sh} = 2 + 0.109\left({N_{Rc} *} \right)^{0.38} \left({N_{Sc} } \right)^{0.50} $$\end{document}Because the particles used in the present study are considerably different from the tablets, beads and crystals that have been used previously, the coefficients of this study are a strict test of existing correlations. Partial agreement of coefficients and recent correlations was observed, but no single correlation can be recommended. Considerable discussion of the many aspects of Harriott's method of correlation also is prese

ISSN:0008-4034    

DOI:10.1002/cjce.5450450402

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

年代:1967

数据来源: WILEY

摘要:

AbstractThe pumping capacities for the propeller and turbine type impellers were derived analytically. The velocity and angle profiles along the blade width of a turbine impeller were also obtained.The applications of the pumping capacities in the simulation of a stirred tank reactor, in the derivation of the power consumption and intensity of segregation, and in the correlation of the heat transfer in a stirred tank, have beer given.

ISSN:0008-4034    

DOI:10.1002/cjce.5450450403

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

年代:1967

数据来源: WILEY

摘要:

AbstractA common problem in the design of mixing and blending equipment is the estimation of the size of the equipment needed to achieve a certain specification. If the statistical properties of the non‐uniformities in the production lots to be blended are known one can calculate by known methods(1)the reduction in the variance of the product properties. Specifications however are normally given not in terms of a variance but in terms of limits. These can be estimated from the variance by assuming a Gaussian distribution. In this paper a methodis discussed whichallows one to calculate these limits directly for some blending problems in which the source of the nonuniformity is due to the production of an off‐grade lot. This not only allows more accurate design procedures, but also gives some insights as to the magnitude of the error made by assuming a Gaussian distribut

ISSN:0008-4034    

DOI:10.1002/cjce.5450450404

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

年代:1967

数据来源: WILEY

摘要:

AbstractA cine‐photographic technique was used to study the evaporation of single droplets of furan, cyclopentane and isopentane rising in water. Measurements were possible over a range from zero to 10% evaporation. The best correlation of the data for the three systems over the measurable range of parameters was:\documentclass{article}\pagestyle{empty}\begin{document}$$ Nu = 0.0505\left({Pe'} \right)^{0.417} \left({\frac{{\rho c}}{\rho }} \right)^{1.25} $$\end{document}All the data was fitted by this equation to within ± 20%.A second correlation with a slightly larger variance\documentclass{article}\pagestyle{empty}\begin{document}$$ Nu = 0.5\left({Pe'} \right)^{0.445} \left({\frac{{\rho c - \rho }}{{\rho c}}} \right)^{1.81} $$\end{document}because of the manner in which the density ratio term varies with % evaporation, was recommended for extrapolation to higher percentage evaporatio

ISSN:0008-4034    

DOI:10.1002/cjce.5450450405

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

年代:1967

数据来源: WILEY

摘要:

AbstractA dilatometric technique was used to determine the total evaporation time of individual drops of furan, isopentane and cyclopentane as they rose in water.The values of total evaporation time were predicted reasonably well for each system by a different equation than was used to correlate the evaporative data for the initial 10% of the evaporative process as reported in Part I of this study. The total evaporation time data were also compared with the correlations given by Klipstein(1), by Sideman and Taitel(2)and with the correlation which was found by the authors to best fit the total evaporative data for the three systems.In agreement with Klipstein(1), the correlation for the overall heat transfer coefficient was found to be one of the form,qA=Cd12.0δt.The rate of rise of an evaporating drop for the conditions used in this study was found to be nearly equal to the instantaneous terminal velocity

ISSN:0008-4034    

DOI:10.1002/cjce.5450450406

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

年代:1967

数据来源: WILEY

摘要:

AbstractA feedforward control system for a CSTR has been constructed and studied theoretically and experimentally.The critical frequency of this control system is greater than the one for a feedback system. For all types of variations, the control of the reactor is improved. At low frequencies, the advantages of this type of control over the feedback system becomes rather negligible.

ISSN:0008-4034    

DOI:10.1002/cjce.5450450407

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

年代:1967

数据来源: WILEY

摘要:

AbstractThe work of Part I on the optimal design of a tubular reactor, in which a second‐order reversible exothermic reaction is being conducted, with recycle of unconverted reactant, is here extended to the cases where either the residence time (reactor length) or the recycle ratio is not specified in advance. Bounds are imposed on the control variable, which is here the local heat transfer conductance from the cooling jacket to the reactor. A gradient technique in control space, accompanied by a search for the optimal switch points, was again effective. With this combined technique singular control arcs were located by the appearance of rapid oscillations of the switching variabl

ISSN:0008-4034    

DOI:10.1002/cjce.5450450408

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

年代:1967

数据来源: WILEY

摘要:

AbstractStarting from the Clapeyron equation and making use of the equivalent expression for the reference state for latent heat of vaporization of pure liquids, namely at 0°K., a new vapor pressure equation is derived as follows:\documentclass{article}\pagestyle{empty}\begin{document}$$ - ln \, Pr = \beta \cdot \chi \left({T_r } \right) $$\end{document}χ(Tr) has been tabulated forTrvalues in the range 0.50

ISSN:0008-4034    

DOI:10.1002/cjce.5450450409

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

年代:1967

数据来源: WILEY

摘要:

AbstractA long‐term program was undertaken in 1960 at the Saskatchewan Research Council to study the feasibility of solution mining potash ore. Appropriate scientific and engineering data for such a study were not available in the technical literature. Consequently laboratory studies were carried out to determine the dissolution rates of potash ore under conditions of natural convection mass transfer from vertical surfaces. The paper summarizes the methods used and the data obtained for the dissolution of potash ore. Both theory and data on the dissolution rates of soluble salts under natural convection conditions are inadequate for industrial purposes and areas of additional research are indicate

ISSN:0008-4034    

DOI:10.1002/cjce.5450450410

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

年代:1967

数据来源: WILEY