摘要:

AbstractA numerical method has been described for the solution of the general equations which depict solidification in the cylindrical coordinate system. The method has been outlined for cooling and solidification of a moving filament of molten polymer. The solution is given in terms of six dimensionless variables: αl/αs,kl/ks,hR/kR,L/[Cps(To−Tc)],To/Tc, and σϵpR(To−Tc)3/kR. Plots are shown for the solution of the heat transfer equations and associated boundary conditions for several values of the dimensionless variables. The method describes the process of cooling and freezing liquids when convective and/or radiative energy losses are considered. The form of the theoretical equation compares very favorably with experiment

ISSN:0001-1541    

DOI:10.1002/aic.690160113

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractNormal pentane and isopentane were evaporated into nitrogen in laminar, concurrent flow in a rectangular channel. Composition profiles within the gas phase were measured, and the evaporation rates were compared with theoretical predictions with satisfactory agreement. The interfacial mole fraction of the evaporating species in the gas phase ranged as high as 0.74. A solution is reported for the Leveque problem under high flux conditions.

ISSN:0001-1541    

DOI:10.1002/aic.690160114

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractAn approach has been developed for predicting rates of interphase mass transfer under conditions of high flux and high concentration level. A rectangular channel device has been used to measure rates of evaporation of four solutes, carbon disulfide,n‐pentane, cyclopentane, and ethyl ether, fromn‐tridecane into flowing nitrogen. The evaporation rate of carbon disulfide agreed with the prediction of the interphase theory up to a carbon disulfide mole fraction of 0.30 in the bulk liquid. For the other three systems, a concentration gradient induced, surface tension driven cellular convection served to increase liquid‐phase coefficients substantially. A correlation was obtained for the effect of this cellular motion on the liquid‐phase mass transfer coef

ISSN:0001-1541    

DOI:10.1002/aic.690160115

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractExperimental results have been obtained for heat transfer to melting ice spheres by measuring the rate of change of apparent weight. It is found that the traditional correlation format of Nusselt number against Rayleigh number is satisfactory only for bulk temperatures above 7°C. Average Nusselt numbers obtained from the sphere experiments are closely related to previous theoretical work with vertical flat plates

ISSN:0001-1541    

DOI:10.1002/aic.690160116

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractA theoretical solution for the impingement flow of a jet with a parabolic velocity distribution is given. Viscous generation and diffusion of vorticity in the jet were neglected. Experimental velocity and pressure distributions measured in an impinging jet of air originating with Poiseuille flow compare well with theory, thus justifying the assumption of inviscid flow. Pressure distributions on the deflecting surface were independent of nozzle height in the range 1 to 12 nozzle radii. For lower nozzle heights the effect of the constriction of flow between the nozzle and the surface followed the predicted behavior.

ISSN:0001-1541    

DOI:10.1002/aic.690160117

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractExact solutions of the boundary layer equations were used to calculate the local mass transfer coefficients for an impinging jet with a parabolic velocity distribution. Boundary conditions were obtained from an inviscid flow solution and also from experimental pressure distributions. Experimental data for the air/naphthalene system were in good agreement with theoretical results. Mass transfer from the impingement surface was independent of nozzle height in the range 0.5 to 12 nozzle radii. For lower nozzle heights the effect of the constriction of flow between the nozzle and the surface led to increased transfer rates near the nozzle wall; data followed the predicted behavior.

ISSN:0001-1541    

DOI:10.1002/aic.690160118

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractPhase equilibria data are presented for the helium‐carbon dioxide system at 253°, 273°, and 293°K. and pressures to 139 atm. Equilibrium is established under flow followed by nonflow conditions, and liquid and vapor samples are isolated without disturbing equilibrium. Liquid‐and vapor‐phase compositions are monitored with miniaturized capacitors, and compressibility factors are computed from resulting dielectric constants. The data are internally consistent and compare favorably with available literatur

ISSN:0001-1541    

DOI:10.1002/aic.690160119

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractA hemispherical bubble, attached to a plate, is surrounded by an initially quiescent and isothermal liquid. By suddenly heating the plate, a thermal gradient over the bubble surface results. Because surface tension is temperature dependent, tangential stresses arise at the bubble surface. The liquid is viscous, and motion in the liquid phase begins. Such motion is an example of thermocapillary flow. This problem, besides being of interest from a fundamental point of view, is of possible concern in the design of space vehicles capable of storing cryogenic fluids for long periods of time in a weightless condition.Solutions to the problem are developed by numerical treatment of the governing equations. Flow and temperature fields, which depend upon the Prandtl and Marangoni numbers, were obtained for Prandtl numbers 1 and 5 and Marangoni numbers from 0 to 100,000.Results show that liquid is pulled toward the intersection of the bubble and the plate, then flows around the bubble surface, and leaves the bubble as a jet. The extent of the jet increases with increasing Marangoni number and decreases with increasing Prandtl number.Thermocapillary flow increases heat transfer (Nusselt number) over that obtained from conduction, but the increase is modest. The Nusselt number increases with the Marangoni number and is insensitive to the Prandtl number. At a Marangoni number of 40,000, the local Nusselt number was increased by a factor of 2. In order for thermocapillary flow to become a dominant heat transfer mechanism, the Marangoni number must exceed 100,000.

ISSN:0001-1541    

DOI:10.1002/aic.690160120

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractTray efficiencies were measured for desorbing ammonia from water by air in a small sieve‐tray column operated in the cycling mode, that is, with alternate flow of vapor and liquid. The actual efficiency improvement obtained was compared with that theoretically possible assuming the liquid flows without mixing when dropped. A mixing model was proposed and the mixing parameter evaluated from the experimental dat

ISSN:0001-1541    

DOI:10.1002/aic.690160121

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY

摘要:

AbstractA modified Redlich‐Kwong equation has been applied to the calculation of phase equilibria in multicomponent systems. The two parameters of the Redlich‐Kwong equation are treated as temperature functions. They are obtained for each pure component from experimental vapor pressures and liquid densities with the help of a generalized fugacity coefficient correlation for saturated vapors. The need to submit coefficients for pure components is thus eliminated. At least one experimental vapor‐liquid equilibrium point is required to establish an interaction constant for each binary system. Applications have been made to binary and multicomponent systems containing hydrocarbons, hydrogen, carbon dioxide, and hydrogen su

ISSN:0001-1541    

DOI:10.1002/aic.690160122

出版商:American Institute of Chemical Engineers    

年代:1970

数据来源: WILEY