ISSN:0001-1541    

DOI:10.1002/aic.690150102

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA dye tracer technique was utilized to measure the residence time distribution of the drops in a spray column, operating with a dispersed or a dense packing of drops, for a wide range of flow rates, in a 15 cm.in diameter, 150 to 160 cm. long column proper.For dispersed packing of drops and for flow rates below the onset of coalescence, the flow of the drops was approximately plug flow, with a variance of the residence time distribution of 0.095. For flow rates above the onset of coalescence within the column, the variance increased sharply to 0.55 and decreased at higher flow rates.For dense packing of drops the variance of the residence time distribution was in the range of 0.1 to 0.5. This variance is attributed to the effect of bypassing water and kerosene near the wall of the column. A mathematical model based on this effect showed reasonable fit with the experimental results. This model predicts an approach to plug flow of the drops for large diameter columns.

ISSN:0001-1541    

DOI:10.1002/aic.690150107

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe use of heuristic structuring strategies in the development of computer programs for the synthesis of process designs is examined. By the employment of selection weights which are adjusted as experience is gained from past successes and failures, the computer is able to learn the sequence of structuring decisions which leads toward the optimal process design. The computer can develop competence in the synthesis of systems in a limited area of technology.

ISSN:0001-1541    

DOI:10.1002/aic.690150108

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractEffects of pore diffusion in the catalytic oxidation of ethylene on copper oxide‐alumina have been studied by varying the catalyst size and maintaining constant the ratio of the tube to the pellet diameter. Hydrocarbon analysis was determined with a flame ionization detector; infrared analyzers were used to determine carbon monoxide and carbon dioxide concentrations. Other reaction products were analyzed with a gas chromatograph. Curvature of the Arrhenius plots and increase in reaction order with temperature indicated a transition region between kinetic control at lower temperatures and pore diffusion control at higher temperatures. A calculation procedure which was developed to predict the conversion considering pore diffusion effects provided satisfactorily agreement between calculated and experimental result

ISSN:0001-1541    

DOI:10.1002/aic.690150109

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe success enjoyed by a laminar flow stability parameter that I previously developed as a generalization of the critical Reynolds number of laminar turbulent transition has occasioned considerable interest in the phenomenological theory underlying the parameter. In this paper an analysis of laminar flow stability is presented which leads naturally to the parameter in a much different manner than originally proposed. The stability parameter is seen to represent the coupling ratio between the rate of change of angular momentum of a deforming fluid element and its rate of loss of momentum by frictional drag. At a certain critical value of this coupling ratio, the element becomes unstable to rotational disturbances. If such disturbances are present, the basic nonlinearity of the momentum transfer process guarantees rapid amplification and generation of a turbulent eddy. The consequnces of the theory are examined for two special fixed boundary classes of motion. The physical interpretation of the parameter is compared with conventional interpretations of the Reynolds number and found to be more fundamentally sound. The application of the theory to moving boundary flows, such as the Couette viscometer, is also discussed and an important physical difference is pointed out.

ISSN:0001-1541    

DOI:10.1002/aic.690150110

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractSimple graphical methods are given for predicting the effectiveness factors of single reactions in particles of various shapes. A collocation procedure is used for small particles, and the known asymptotic solution is used for large particles. Multiple steady states and variable fluid properties can be handled directly. Examples are given for several nonlinear reaction rate laws.

ISSN:0001-1541    

DOI:10.1002/aic.690150111

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe rate of attrition of a catalyst sample, of a single particle size, can be expressed by a simple function of initial diameter and time. The initial rate is a function of initial diameter, whereas the decrease in attrition rate of a catalyst of a given size as it ages depends only on time.The attrition equation for a single size of particles is introduced into the particle size distribution function and, through mathematical analyses, yields a relationship for the attrition of a full size‐range catalyst. The form of this relationship, which includes terms for attritability and severity of attrition conditions, is verified by laboratory and commercial attrition data on two full‐range catalysts. The size distribution of an attrited sample is not expressible in simple analytical form, but is readily obtained by numerical analy

ISSN:0001-1541    

DOI:10.1002/aic.690150112

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractAn approximate solution is presented for the countercurrent parallel plate exchanger with laminar flow. With the use of the integral method, the problem is reduced to one of solving a pair of first‐order differential equations in a straightforward manner. Comparisons between the results of this work and those obtained from a more elaborate orthogonal expansion technique are found to be excellen

ISSN:0001-1541    

DOI:10.1002/aic.690150113

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractThe evaporation ofn‐decane into air from the surface of Celite particles, has been used for the establishment of mass transfer factors for both packed and fluidized bed systems. For these calculations log mean partial pressure differences were used. Actual concentration profiles of the transferable component were also experimentally measured by monitoring, at different bed heights, the concentration ofn‐decane vapor present in air used as the carrier gas. This was made possible through the use of an extremely sensitive hydrocarbon analyzer. The resulting profiles were used to obtain, by graphical integration, the actual driving force prevailing for each run. A nearly one‐to‐one correspondence was found to exist between the actual driving force and the corresponding log‐mean value for both packed and fluidized

ISSN:0001-1541    

DOI:10.1002/aic.690150114

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY

摘要:

AbstractA knowledge of liquid‐film flow rates is important for design purposes when accurate predictions are required of the conditions under which dryout heat flux occurs in nuclear reactors and boilers. Liquid‐film flow rates were measured for a steam‐water mixture in cocurrent, upward annular flow in a tube at a pressure of 1,000 lb./sq.in.abs. Sinters located at the test section exit were used to extract the liquid film after the method of the Harwell group. Sinter lengths of 2, 1, and 1/2 in. were employed to investigate the effect of length on the extracted liquid flow rates. The test section was a stainless steel pipe of inside diameter 0.493 in., approximately 200 diam. in length. The total mass flux ranged from 0.2 to 0.7 × 106lb.m/hr.sq.ft. and the quality varied from 0.3 to 0.92.The experimental film flow rates were found to increase with decreasing quality. In the range of parameters investigated, the curves of film flow rate at constant quality vs. mass flux showed a maximum at a fixed value of steam velocity. At the same total mass flux and quality the film flow from the 1/2 in. sinter was lowest, suggesting that the crests of high amplitude roll waves overshot the sinter. Film flow rates were consistently higher than the theoretical predictions using Levy/s model. About one‐third of the measured flow rates were twice as high as p

ISSN:0001-1541    

DOI:10.1002/aic.690150115

出版商:American Institute of Chemical Engineers    

年代:1969

数据来源: WILEY