摘要:

AbstractCapital cost correlations are given for liquid moving equipment. Correlations available in the literature and current data from suppliers, contractors, consultants and industry are compared on a consistent basis. Forty‐three graphs show the relative magnitudes of the different correlations, and the recommended correlation for each type of equipment is given. Some factors are given on the costs of installing liquid moving equipmen

ISSN:0008-4034    

DOI:10.1002/cjce.5450570401

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

年代:1979

数据来源: WILEY

摘要:

AbstractMeasurement of response curves to an imperfect pulse signal were carried out in a liquid flowing cocurrently with a gas at two positions in a packed bed. Three types of ceramic packing were investigated, viz. spheres, solid cylinders and Raschig rings, all of nominal size 6 mm. The liquids used were water and a corn sugar solution of viscosity 9.13 mPa·s. The curves were analyzed by means of two models: the axially dispersed plug flow model and the Markov chain model; the latter was solved for this purpose. Empirical correlations for the model parameters were obtained

ISSN:0008-4034    

DOI:10.1002/cjce.5450570402

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

年代:1979

数据来源: WILEY

摘要:

AbstractVortex rings have been formed in water by impulsive flow through an orifice, and mixing effects due to the lings have been measured. Laboratory tests on the mixing of stratified layers of salt solution by vortex rings formed at a 6.35 cm diameter orifice have indicated that Froude number is an important factor in determining the energy efficiency of mixing. Field tests using a 25.4 cm orifice in Hamilton Harbour (18 m depth of water) have shown a small mixing effect. Further experiments with a 25.4 cm orifice in a test tank have shown that the vortex rings have a range of at least 30 m.

ISSN:0008-4034    

DOI:10.1002/cjce.5450570403

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

年代:1979

数据来源: WILEY

摘要:

AbstractA numerical approach for the modeling of thermal effects in turbulent mixing of large flows with uniform eddy viscosities and eddy diffusivities is presented. The distinctive features of this approach are the simultaneous compliance of mass and momentum equations, and accurate predictions of the surface waves and pressure distribution in flow fields with arbitrary bottom geometry. The numerical approach employs centered three‐point finite difference expressions for the first and second spatial derivatives with unequal mesh size and a forward time integration. Numerical stability analysis of the governing equations is utilized to select optimum space and time increments for numerical integratio

ISSN:0008-4034    

DOI:10.1002/cjce.5450570404

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

年代:1979

数据来源: WILEY

摘要:

AbstractAn experimental study of convective heat transfer from hot air to the solid charge and walls in a non‐fired rotary kiln is reported. Ottawa sand was heated by passing it counter‐current to a flow of preheated air in a 2.5 m × 0.19 m I.D. rotary kiln. Axial temperature profiles of gas, wall and solids were measured. Local and average convective heat transfer coefficients from gas to solids and from gas to wall were determined assuming plug flow of gas and solids. Solid feed rates to 1750 kg/m2h and air rates to 3300 kg/m2h were investigated at rotational speeds to 6 r/min, holdup ratios to 17% and gas temperatures from 350–590 K. The gas/solids convective coefficient was found to depend on the gas through‐put and to a lesser extent on solids holdup and rotational speed. Over the range tested, the angle of kiln inclination, solids throughput and particle size showed no significant effect on heat transfer. Gas/wall coefficients were about a factor of ten below gas/solid coefficients. Heat transfer results are compared to the limited data available in the literature, and to commonly used equations. Correlations of the experimental data on gas/solids, and gas/wall coefficients are presented; data from the literature on the wall/solids heat transfer coefficient are su

ISSN:0008-4034    

DOI:10.1002/cjce.5450570405

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

年代:1979

数据来源: WILEY

摘要:

AbstractConjugated heat transfer in steady state was studied, assuming the interfacial reaction to be instantaneous and the flow to be a fully‐developed laminar condition. The thermal boundary condition at the outer surface of the duct wall is specified as the first kind or the third kind. Influences of the interfacial reaction, the conductance of the wall and the external convection on the heat transfer characteristics were found to be substantial through calculated numerical results of the interfacial temperature and the local Nusselt number. Cases with uniform interfacial heat source and without it were also examined under the third kind boundary conditio

ISSN:0008-4034    

DOI:10.1002/cjce.5450570406

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

年代:1979

数据来源: WILEY

摘要:

AbstractDropwise condensation of different steam‐air mixtures on three substrate materials (copper, aluminium and nickel) is studied. For each steam‐air mixture, the heat flux, the heat transfer coefficient and the surface temperature are observed to be highest on copper and lowest on nickel substrates for the same identical test conditions. The above heat transfer variables are related to the bulk properties of the substrate.It is concluded that the presence of non‐condensable gases is an inhibiting influence on the heat transfer performance in the condensation of steam. The normalized variables\documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{h_i \left(\eta \right)}}{{h_i \left(o \right)}} $\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{T_{si} \left(\eta \right)}}{{T_{si} \left(o \right)}} $\end{document}are found to be functions of the air concentration

ISSN:0008-4034    

DOI:10.1002/cjce.5450570407

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

年代:1979

数据来源: WILEY

摘要:

AbstractA mathematical model has been developed from the kinetic theory of gases. The model accounts for the heat transfer performance during dropwise condensation of different steam‐air mixtures on surfaces of various materials. In the development of the analytical model, the droplet surface is assumed to be in equilibrium or very near to equilibrium conditions with the fluid in contact, whereas the steam at the liquid‐vapour interface is visualized to be in the saturated state. It is concluded that a minute fraction of the part of the substrate surface covered by liquid droplets (the minute fraction is referred to as the effective area) is most effective for the flow of heat and also it is concluded that the contribution to the heat transfer by the bare area is negligible. In the investigation it is deduced that the effective area may consist of: a) droplets with very small radii, and b) tiny portions of the liquid surfaces of large droplets. The tiny portion of the liquid surface can be visualized to lie in the vicinity of the droplet perimeter. The effective area is found to vary from one surface to another according to the substrate material. Concerning the influence of the presence of non‐condensable gases, the effective area is found to decrease rapidly with the increase of the air concentr

ISSN:0008-4034    

DOI:10.1002/cjce.5450570408

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe hydrodynamics of liquid‐liquid slug flow have been studied for several organic components in water, in vertical tubes of diameters between 4.08 and 18.99 mm. Under conditions such that the slug flow is laminar and stable, mass transfer of sparingly soluble organic components (n‐butanol, n‐pentanol and methyl i‐butyl ketone) to water has been measured by observing the shrinkage rates of slugs. The observations are compared with predictions based upon the Higbie penetration model and the calculated velocity profile due to slug flow. It is concluded that the slug flow technique could be useful in studying the rates of reaction‐accompanied e

ISSN:0008-4034    

DOI:10.1002/cjce.5450570409

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

年代:1979

数据来源: WILEY

摘要:

AbstractConcentration multiplicity and stability for autocatalytic reactions of the type A + R → R + R with overall rate expression\documentclass{article}\pagestyle{empty}\begin{document}$ -{\rm r}_A = {\rm kC}_A^m {\rm C}_R^n $\end{document}in a continuous stirred‐tank reactor (CSTR) is analyzed in a rigorous way in this paper. Important parameters for multiplicity criteria are reaction orders m and n, dimensionless space time Θ, and the ratio P of feed concentration of R to that of A. Necessary conditions for the system to have multiple exit concentrations (conversions) are defined in the (m, n, P) space. Multiplicity is guaranteed by limiting the dimensionless space time in a proper range in addition to the necessary conditions. Stability analysis shows that there is no periodic oscillation for the system. The upper and lower steady states of multiple solutions are both asymptotically stable. A unique steady state is globally st

ISSN:0008-4034    

DOI:10.1002/cjce.5450570410

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

年代:1979

数据来源: WILEY