Theoretical and experimental study of the fluid- particles interaction on the turbulence in dispersed fluid-particles flows (DSF.4996)

Turbulent fluid flows with particles are encountered in a wide variety of industrial applications. Examples are: spray drying, pneumatic transport, slurry transport, abrasive water-jet cutting, pulverized-coal fired furnaces, catalytic cracker riser reactor, etc. An accurate computation method for such flows is important in order to be able to interpret and correlate experimental data and to support process development and scaling-up of applications. For that reason much interest has been devoted to dispersed multiphase flows, and in particular to the possibility of modeling such flows. There have been significant advances in the past few years because of enhanced computational capabilities. The field is evolving from one in which empiricism played a major role to one in which analysis and modeling can now be used. Still, the technology is far from mature and many challenges remain.

One of these challenges is a realistic description of the influence of the fluid-particles interaction on the turbulence of the fluid and of the particles in the fluid-particles mixture, in particular at higher particle concentrations (say 10 % by volume or higher). At such concentrations influence of the particles on the turbulence of the fluid and the particles of the mixture may no longer be neglected, and has to be incorporated in the modeling to make realistic predictions for fluid-particles flows possible. Therefore, Felderhof and Ooms (1989, 1990), Felderhof and Jansen (1991), Ooms and Schinkel (1998a, 1998b), and Jansen and Ooms (1998) developed a theory (based on a "microscopiC model for the dynamics of particles in an incompressible fluid) for the fluid-particles interaction in turbulent, dispersed flows. Also the hydrodynamic interaction between the particles is included. With this theory the influence of relevant particle parameters (concentration, diameter, density) and fluid parameters (turbulence intensity, length scales, density) on the turbulence properties of the fluid and the particles of the mixture can be investigated. First results show that this influence can be significant.

The aim of the project is to validate the theoretical predictions by accurate laboratory experiments. Particular attention will be paid to the influence of the relevant parameters on the turbulence intensity of the fluid and of the particles of the mixture and on the dispersion of the particles. In the theory some simplifying assumptions have been made. Therefore it will be extended, so that it will be more generally applicable.
Finally, the theory will be included in an existing computer program for the calculation of turbulent, dispersed fluid-particles flows to study the influence of fluid-particles interaction on the turbulence and other flow properties for some practical flows.

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Er zijn drie bedrijven en twee onderzoeksinstellingen bij dit project betrokken.

Prof.dr.ir. G. Ooms
J.M. Burgerscentrum
Rotterdamseweg 145
2628 AL Delft

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