ISSN:0001-1541    

DOI:10.1002/aic.690080103

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690080105

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractNumerical and graphical methods are presented for estimating the temperatures and partial pressures at the surfaces of catalyst particles for gaseous reactions in flow systems. The errors resulting in the interpretation of catalytic reaction‐rate data, where surface conditions are assumed to be those of the ambient gas stream, are presented. A numerical method of evaluating the reaction model with nonisothermal surface conditions is indicate

ISSN:0001-1541    

DOI:10.1002/aic.690080106

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractAn analysis of radiant interchange is made which takes account of possible surface variations in incident radiation flux, heat transfer, and leaving radiant flux. This represents a generalization of standard calculation methods which postulate that the radiant fluxes and heat transfer are uniformly distributed on a surface. Consideration is given to pairs of simply‐arranged surfaces having different emissivities, one of which is essentially black. The surface temperatures may be arbitrarily different. The generalized analysis reveals that there may be significant variations in the local heat transfer along a surface, and this stands in contrast to the results of standard (and more approximate) calculation methods. The over‐all heat transfer results are also compared with those predicted by the standard calculation procedure. For the surface which is essentially black the errors arising in the standard procedure are found to be tolerable as long as the net over‐all heat transfer exceeds 20% of the radiant emission. For the nonblack surface the two methods are in agre

ISSN:0001-1541    

DOI:10.1002/aic.690080107

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractData on pressure drop in two‐phase, single‐component fluid flow, both with and without heat transfer, are presented in terms of the Lockhart and Martinelli correlation parameters. The fluids used were trichloromonofluoromethane and hydrogen.The results are compared with the correlation curve recommended by Martinelli and Nelson and give frictional pressure drops that are about 40% lower than the curve. The reasons for the deviations are discussed in terms of the effects of friction factors, the existence of metastable equilibrium, accuracy of data and instrumentation, and calculation procedures.It is concluded that the Martinelli and Nelson correlation and a simple momentum pressure drop computation can be superposed to predict roughly the total pressure drop in tubes containing steady state, two‐phase, single‐component fluid flow with appreciable vapor

ISSN:0001-1541    

DOI:10.1002/aic.690080108

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractMain stream velocity profiles have been obtained by means of impact probes for the steady, isothermal flow of water in three smooth, concentric annuli having widely different diameter ratios. The point of maximum local velocity has been determined, thus permitting the ratio of skin frictions at the inner and outer boundaries to be calculated. Previously published data on pressure drop have been used to obtain separate friction factor correlations for the two surfaces. Attention has been centered on the transition range, where the position of maximum velocity is a function of both the diameter ratio and the Reynolds number.

ISSN:0001-1541    

DOI:10.1002/aic.690080109

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractTurbulent heat transfer coefficients have been measured at the surface of single bubbles formed by injecting steam into a subcooled water stream at atmospheric pressure. Depending upon the steam flow rate (0.4 to 1.5 g./min), the water temperature (80° to 180°F.), and the water velocity (0.9 to 7.2 ft./sec.) the bubbles ranged from small, smooth, ellipsoidal bubbles, similar to those observed in highly subcooled nucleate boiling, to large, irregular bubbles which oscillated in size. The bubble frequencies were in the range 200 to 2,500 cycles/sec. and the surface heat transfer coefficients 13,000 to 320,000 B.t.u./(hr.) (sq. ft.) (°F.). Because of these exceptionally high heat transfer coefficients a significant fraction of the total heat flow in Gunther's subcooled boiling experiments is estimated to be attributable to latent heat transpo

ISSN:0001-1541    

DOI:10.1002/aic.690080110

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractThe transfer of mass, heat, and momentum past a single sphere, 2.02 in. in diameter, was experimentally investigated for the turbulent flow of air betweenNRe= 1,750 andNRe= 8,922. The data resulting for the vaporization of water from the spherical surface verify the existence of the analogy between mass and heat transfer.Measurements were made to account for the total drag and form drag of the sphere. The total drag was obtained by directly accounting for the force exerted, while the form drag was determined from static pressure measurements around the surface of the sphere. The resulting friction factors for total dragfand for form dragfpwere found to be of the same order of magnitude, thus making it impossible to account for the friction factor due to shear drag at these Reynolds numbers. Consequently it is not possible to determine if the analogy between mass and heat transfer can be extended to include the transfer of momentum for flow past single spheres at these conditions, although the results of this study cast considerable doubt on such an extension of this analogy.

ISSN:0001-1541    

DOI:10.1002/aic.690080111

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractEquimolal countercurrent diffusions runs were made in a two bulb diffusion cell with the system hydrogen, nitrogen, and carbon dioxide. The initial bulb compositions were chosen so that various types of ternary interactions occurred. These interactions were well‐described by the Maxwell‐Stefan equations. The average deviation of the experimental mole fractions for all runs from those predicted by the Maxwell‐Stefan equations was 0.45 m

ISSN:0001-1541    

DOI:10.1002/aic.690080112

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY

摘要:

AbstractA new method for measuring isothermal rates of heterogeneously catalyzed gas reactions is described. The method involves a differential reactor incorporated in a recycling system and affords ease of control, accuracy, and many rate measurements in one run.The results for the reaction system investigated show that four reactions are important: the dehydration of ethanol to ethylene, the reaction of ethanol to form diethyl ether, the dehydration of diethyl ether to ethylene, and the reaction of diethyl ether to form ethanol.It is also shown that the rate controlling steps are the monomolecular surface reactions for the two dehydrations and for the formation of ethanol from diethyl ether, and the bimolecular surface reaction for the formation of diethyl ether from ethanol.The values and the temperature dependence of all pertinent rate and adsorption constants are determined and reported, and they are shown to correlate very well the data up to 80% conversion.

ISSN:0001-1541    

DOI:10.1002/aic.690080113

出版商:American Institute of Chemical Engineers    

年代:1962

数据来源: WILEY