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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

INVESTIGATION OF MASS TRANSFER ON MACRO- AND MICROSCALE BETWEEN AN INJECTED DYES MIXTURE AND A BULK FLUID

Get access (open in a dialog) DOI: 10.1615/IHTC13.p10.70
11 pages

要約

Many exothermic homogeneous chemical reactions are performed in large volume vessels. Many of them have to be activated by homogeneous catalysis. In case of a runaway-reaction a reaction inhibitor has to be injected. In both cases small quantities of liquid must be homogeneously distributed throughout the whole large-volume vessel. A minimum concentration of the catalyst or of the inhibitor has to be guaranteed after a short time to be equally distributed inside the whole volume.
Experiments are performed in which small quantities of a liquid mixture of two dyes are introduced through a nozzle into a large liquid volume. The emerging concentration fields of the dyes on the bulk liquid are locally and temporally visualized by a tomographic measurement method. One dye is inert and serves as tracer for the mass transfer on the macroscopic scale, due to convection. The reaction can occur when the mass transfer on the microscopic scale by means of diffusion takes place. Through the visualisation of the discolouring reacting dye information on transport phenomena molecular scale is achieved. The applied measurement method is the tomographic two-wavelengths photometry. Two lasers are employed whose emitted lights wavelengths are differently absorbed by the two dyes. The two lasers beams are superimposed, divided in three beams and expanded to illuminate the vessel in three different directions. The beams leaving the vessel are conveyed to three CCD colour cameras, which grab the projections of the dyes concentrations.
The concentration fields of the dyes inside the vessel are tomographically measured and reconstructed by measurements of the laser light transmitted through the vessel and by application of the Lambert-Beer's law. Thanks to the illumination of the vessel in three directions, it is possible to calculate the spatial distribution of both dyes.
By comparing the concentration fields for different injection parameters like momentum of fluid flow and volume of the injected liquid, nozzle geometry and bulk liquid viscosity, the concentration fields between injected and bulk liquid are investigated on the macro- and microscale.