摘要:

AbstractCurrent status of crystallizer design. This paper surveys current knowledge in designing large scale crystallizers. The volume of a crystallizer depends on the desired mean crystal size, the suspended magma density and the permissible supersaturation, the latter determining the growth velocity and the nucleation rate. Different techniques for measuring the rate of crystal growth are outlined, as are also the methods used in its calculation, which are based upon various models of crystal growth. In designing a large scale crystallizer the phenomena of fluid dynamics and heat transfer must be taken into consideration. The paper deals with these two areas in detail and discusses problems associated with the control of population balance in the slurry.

ISSN:0009-286X    

DOI:10.1002/cite.330500202

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractUse of holographic interferometry for nondestructive testing of materials and components. Holographic interferometry represents a useful tool for measurement of deformations over large surface areas of any constructional or plant components. Application of the stresses encountered in operation reveal weak spots endangering the component owing to improper production methods or to material defects. Furthermore, particularly small material defects can be detected on generation of waves by an impact loading; interference at cracks is clearly displayed in the holographically stored interference picture.

ISSN:0009-286X    

DOI:10.1002/cite.330500203

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractMethods of measuring convective mass transfer. The principal methods of measuring convective transfer of momentum, heat, and mass are surveyed on the basis of the three‐fold analogy existing between the transfer of momentum, heat, and mass. The most simple and most sensitive method is the mass transfer technique based on the principle of absorption with chemical reaction and coupled colour reaction. It is shown by selected examples that this measuring technique is already developed to the point where it serves adequately for the solution of most complex problems met with in practice. It is distinguished by its high accuracy of measurement, simple application, high local resolution, and its utilizability both for developable as well as for undevelopable surfaces. By way of the local mass transfer observable as colour‐intensity distribution it also affords a simple and illustrative means of making flow processes on solid surfaces visible. The quantitative evaluation is accomplished by reflectance photometry; quantitative image processing methods are available for complex distributions. In addition, it is shown that the mass transfer technique is also suitable for practical utilization as a method for measuring turbulence. The measuring principle is based on the extremely high dependence of the length of transitional separation bubbles in the nose section of flat plates of finite thickness in longitudinal flow on the turbulence intens

ISSN:0009-286X    

DOI:10.1002/cite.330500204

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractAxial mixing in liquid/liquid countercurrent extractors. Methods are considered for the determination of longitudinal mixing in many countercurrent extractors. It is found that only the single phase mixing of the continuous phase can be accurately determined; with certain reservations this also applies to the disperse phase. In the case of RDC and ARD in particular, correlations are available which permit calculation of Bodenstein numbers for both phases. Such scale‐up calculations are not recommended for many extractors. It is very important to establish adequate correlations for calculation of mixing of the disperse phase in order to obtain exact dispersion heights in connection with those of the continuous phas

ISSN:0009-286X    

DOI:10.1002/cite.330500205

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractHeat transfer with change of phase in chemical engineering processes. Heat transfer with change of phase in multicomponent fluid systems depends on whether the liquid is homogeneous or consists of several phases. In condensation of vapours where a homogeneous liquid is formed, the temperature of the interface may change considerably, an effect which is mostly neglected in heat transfer calculations. In cases where the liquid consists of several phases heat transfer coefficients may be evaluated to a good approximation. However, an additional heat resistance must be taken into account when the vapour condenses at an immiscible liquid interface. Heat transfer coefficients for boiling of homogeneous liquid mixtures may be derived from those of the pure components and an additional term allowing for the different composition of liquid and vapour. For multicomponent mixtures this term may be evaluated from the terms of the corresponding binary systems. Heat transfer in boiling of immiscible liquid mixtures is mainly governed by the physical properties of the liquid phase adjacent to the heating wall.

ISSN:0009-286X    

DOI:10.1002/cite.330500206

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractAdvances in Process Research by Radionuclide Techniques. Modifications and transformations of materials and their technical implementation in process systems require movement of materials. Radionuclide techniques can greatly help in understanding and describing these mechanisms. Their advantage lies in the contactless measurement of radioactively labeled flows of materials by the radiation emitted even through thick walls of equipment. Even under rigorous process conditions (high pressures, high temperatures), for instance, residence time distribution functions can be determined at any point in a process system without interfering with the system. This specialized measuring technique is demonstrated by three examples selected from various fields of process technology. Radioactive tracer studies performed on a rotary kiln helped, inter alia, to establish a subdivision into process zones and to pinpoint areas of dust generation. Mixing and feeding actions were studied in a twin screw extruder equipped with a special screw and mixer disk arrangement. Tracer experiments conducted in two secondary settling basins indicate the differences in the mechanisms of movement of the aqueous phase if the mean residence time and the residence time distribution may be influenced not only by hydraulic loads, but also by design variants of the overflow flumes.

ISSN:0009-286X    

DOI:10.1002/cite.330500207

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500208

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500209

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500210

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500211

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY