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Droplet process modeling

Theoretical Calculations and Numerical Modeling of Droplet Processes... [Pg.315]

As for normal liquids, modeling of droplet processes of melts provides tremendous opportunities to improve the understanding of the fundamental phenomena and underlying physics in the processes. It also provides basic guidelines for optimization and on-line control of the processes. This section is devoted to a comprehensive review of process models, computational methods, and numerical modeling results of the droplet processes of melts. The emphasis of this section will be placed on the droplet processes in spray atomization for metal powder production, and spray forming for near-net shape materials synthesis and manufacturing. Details of these processes have been described in Ref. 3. [Pg.349]

The fundamental issues to be addressed in the process modeling include spray enthalpy, gas consumption, spray mass distribution, microstructure of solidified droplets, and droplet-substrate interactions. The effects of atomization gas chemistry, alloy composition and operation conditions on the resultant droplet properties are also to be investigated in the process modeling. [Pg.349]

Numerous 2-D models have been developed to simulate droplet deformation processes during impact on a smooth surface. Most of these models assumed axi symmetric deformation of a spherical or cylindrical droplet. The models may be conveniently divided into two groups, i.e., compressible and incompressible. [Pg.381]

There have been books on droplet-related processes. However, the present book is probably the first one that encompasses the fundamental phenomena, principles and processes of discrete droplets of both normal liquids and melts. The author has attempted to correlate many diverse mechanisms and effects in a single and common framework in an effort to provide the reader with a new perspective of the identical basic physics and the inherent relationship between normal liquid and melt droplet processes. Another distinct and unique feature of this book is the comprehensive review of the empirical correlations, analytical and numerical models and computer simulations of droplet processes. These not only provide practical and handy approaches for engineering calculations, analyses and designs, but also form a useful basis for future in-depth research. Therefore, the present book covers the fundamental aspects of engineering applications and scientific research in the area. [Pg.534]

In keeping with the assumptions of the classical quasi-steady droplet combustion models by Spalding (I) and Godsave (2), the combustion process is assumed for this investigation to take place instantaneously at a fiame surface where the fuel and oxygen react stoichiometrically and completely. Then the rate at which fuel is reacted at a fiame surface located at r = b can be expressed in terms of the delta function by ... [Pg.35]

The second stage of process modeling consists in applying a reliable correlation between atomization parameters, liquid properties, and droplet size. Numerous experimental studies have been carried out, and several equations have been proposed to relate droplet size to nozzle design, atomization energy, and physical and flow properties of the gas and liquids employed. Although some published models have proved... [Pg.276]

The batch suspension polymerization system considered in the present study, is schematically shown in Figure 1. It consists of a well mixed jacketed vessel. In the suspension polymerization process, liquid styrene is dispersed in the continuous aqueous phase by the combined action of stirring and the use of suspending agents. The reaction takes place in the monomer droplets. For modelling purposes, each droplet can be treated as a small batch bulk polymerization reactor. The heat of polymerization is transferred from the dispersed droplets to the aqueous phase and then to the coolant flowing through the reactor s jacket. [Pg.174]

Multi-purpose CFD codes are nowadays a frequently used and well accepted tool in academia and industry. Already the available standard codes must be regarded as powerful tools that can be successfully applied to various technical disciplines including combustion processes. In this field at present the real value in CFD calculations lies in predicting trends that occur when operational conditions are changed. This statement is true for the above presented ash deposition predictions as well as for the NO emission predictions and is validated for both cases with experimental data. However, in the future the real power of CFD codes lays in the possibility to extend and adjust them with process specific data to tailor-made tools applicable to address individual technical problems and specific questions. The successfully developed and validated simplified black liquor droplet combustion model presented in this paper proves this assessment. [Pg.814]

The varied interfacial tensions in the microflow processes we discussed above have to be measured online using fluid dynamic models. In recent years, a series of methods have been developed to determine the dynamic interfacial tension, basing on the measurements of droplet size, droplet deformation, and the pressure drop across the droplet. Using the average diameters of droplets generated from joint channels, such as T-junction and cross-junction microchannels, the interfacial tension at the droplet pinch-off moment was obtained. This method should be based on a reliable droplet size model, which contains interfacial tension. In the previous study, the dynamic interfacial tension between Hquids at the droplet pinch-off... [Pg.179]

The integral spray-process modelling will take account of three sub-processes, that is liquid sheet fragmentation, droplet spray, and particle formation. In the CFD-based modelling approach, the liquid fragmentation will be modelled based on a modified volume of fluid (VOF) approach, while the droplet spray and particle... [Pg.682]


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See also in sourсe #XX -- [ Pg.349 ]




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