摘要:

A review is presented of the parameters influencing the nucleation of scale from natural waters on a heat transfer surface and its prevention. Little is known about this phenomenon in comparison to subsequent scale growth. The importance of variations in pressure and temperature, which directly change the saturation limit of the scaling species, are emphasized. The influence of fluid motion, the type of heat transfer surface material and its condition, on scale nucleation, is also discussed. Both chemical and physical methods of water treatment used to prevent nucleation and growth of scale are reviewed.

ISSN:0098-6445    

DOI:10.1080/00986447808960458

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The effect of the gas and liquid flow rates on the mass transfer rate in laminar gas streams in wetted-wall columns with countercurrent gas-liquid flow was studied. An approximate analytical solution was obtained for the average gas-phase Sherwood number as a function of the gas-phase Graetz number and the dimensionless interfacial gas velocity. Experiments were carried out on the absorption of ammonia into aqueous sulfuric acid solution and of methanol vapor into water, using two columns of different lengths. The agreement between the experimental and the predicted effects of both gas and liquid flow rates on the gas-phase mass transfer rate was found to be fairly good.

ISSN:0098-6445    

DOI:10.1080/00986447808960459

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Mass transfer to the wall and a homogeneous first-order chemical reaction are considered separately for laminar Axial dispersion coefficients for steady-state systems computed from exact solutions for the concentration profiles are shown to be strong functions of axial position. For the homogeneous first-order reaction case, the axial dispersion coefficient is a function of the reaction rate constant.

ISSN:0098-6445    

DOI:10.1080/00986447808960460

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0098-6445    

DOI:10.1080/00986447808960461

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0098-6445    

DOI:10.1080/00986447808960462

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The usual models for predicting the effect of liquid mixing assume a diffusion model as is reasonable for the foam and froth regimes. Here a one-dimensional spray regime model is developed with finite spray “throw,” allowing for inlet and outlet conditions and the effect of spray mixing on tray efficiency is evaluated. The extension to less restricted models is indicated.

ISSN:0098-6445    

DOI:10.1080/00986447808960463

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

This work presents a complete theoretical study of the process of convective diffusion from a non-uniformly distributed source in a non-Newtonian fluid flowing through a straight tube. The influence of the governing parameters on the dispersion process is studied and the results are examined in terms of the interaction of rheology, fluid mechanics and diffusion. Experimental studies have been conducted to obtain the diffusivity values of NaOH in aqueous polymer solutions and provide the first test of the potential of this technique for diffusivity measurement in difficult systems.

ISSN:0098-6445    

DOI:10.1080/00986447808960464

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Fick's first law is compared with the Stefan-Maxwell equation indescribing the compositon of a constant evaporating mixture. The maximum deviation between the two predictions varies with the system: 17% for toluene-ethanol solutions evaporating in air, 8.5% for benzene-methanol solutions in air.

ISSN:0098-6445    

DOI:10.1080/00986447808960465

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor