Hydrodynamics future research

To provide the pr equisite knowledge for designing the three-phase fluidized-bed reactors with new modes, the hydrodynamics such as phase holdup, mixing and bubble properties and heat and mass transfer characteristics in the reactors have to be determined. Thus, in this study, the hydrodynamics and heat and mass transfer characteristics in the inverse and circulating three-phase fluidized-bed reactors for wastewater treatment in the present and previous studies have been summarized. Correlations for the hydrod3aiamics as well as mass and heat transfer coefficients are proposed. The areas wherein future research should be undertaken to improve... 

In the section on bubble column reactors, the hydrodynamic parameters needed for scale-up are presented along with models for reaction and heat transfer. The mixing characteristics of colunms are described as are the directions for future research work on bubble column reactors. 

The nature of these transitions and consequences in terms of electronic and hydrodynamical properties are presently discussed controversially (1-3). Thirdly, a rather large number of soluble PDA has now become available, so that substituent effects such as H-bonding may be separated from the properties of the "pure" PDA backbone in addition substituent effects as such can now be easily studied. It is convenient to discuss the problems of present and possible future research following an e3q>erimental classification due to the lack of theoretical understanding. 

Another hydrodynamic device that could be adapted for future catalytic research is the wall j et which was first described by Glauert [74] and developed mainly by Albery [75-77], Here the mixed solution would be forced through a jet so as to impinge normally on to the centre of a stationary catalytic disc. As the vertical flow lines in Fig. 8 show, only fresh solution that has just come through the jet can reach the disc surface [75,76]. The average thickness of the diffusion layer has been shown to be [77, 78]... 

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