| Resumo: |
This project concerns the process of mass transfer from surfaces immersed in packed beds of granular inerts through which water flows. Our team pioneered the analysis of such processes in truly scientific terms (i.e. in terms of a realistic detailed physical model), which correspond to two papers distinguished for their quality, by the IChemE, in 1988. Our main interest at the time was in the combustion of carbon particles in fluidised beds and that problem was successfully tackled soon afterwards. We then progressed towards adapting the same methodology to the measurement of transverse dispersion coefficients in flow through packed beds and in certain limiting cases that leads to an interesting method for the measurement of the Molecular diffusion coefficient in liquids. The continuation of that line of work led us to the completion of an overall map of dispersion data for flow through packed beds, which is a very useful piece of information for chemical and environmental engineers as well as for geophysicists concerned with flow through porous ground.
In our most recent research we started turning our attention to what happens at a significant distance from the dissolving/reacting buried surface. This we did by solving nummericaly the equations for flow and diffusion/dispersion around a buried sphere, exposed to a uniform stream, so as to determine the concentration contour surfaces for each level of contaminant concentration. The results obtained are interesting, but the computational work requires now some form of experimental validation.
The purpose of the present project is partly to provide that experimental validation, but it is easier to work in the laboratory with geometries that deviate significantly from that of convection/diffusion from a sphere . A geometry which is much more easily tested in the laboratory is flow along a long prismatic granular bed, with rectangular cross section, with mass transfer from a rectangular piece of the pavement.  |
Resumo
This project concerns the process of mass transfer from surfaces immersed in packed beds of granular inerts through which water flows. Our team pioneered the analysis of such processes in truly scientific terms (i.e. in terms of a realistic detailed physical model), which correspond to two papers distinguished for their quality, by the IChemE, in 1988. Our main interest at the time was in the combustion of carbon particles in fluidised beds and that problem was successfully tackled soon afterwards. We then progressed towards adapting the same methodology to the measurement of transverse dispersion coefficients in flow through packed beds and in certain limiting cases that leads to an interesting method for the measurement of the Molecular diffusion coefficient in liquids. The continuation of that line of work led us to the completion of an overall map of dispersion data for flow through packed beds, which is a very useful piece of information for chemical and environmental engineers as well as for geophysicists concerned with flow through porous ground.
In our most recent research we started turning our attention to what happens at a significant distance from the dissolving/reacting buried surface. This we did by solving nummericaly the equations for flow and diffusion/dispersion around a buried sphere, exposed to a uniform stream, so as to determine the concentration contour surfaces for each level of contaminant concentration. The results obtained are interesting, but the computational work requires now some form of experimental validation.
The purpose of the present project is partly to provide that experimental validation, but it is easier to work in the laboratory with geometries that deviate significantly from that of convection/diffusion from a sphere . A geometry which is much more easily tested in the laboratory is flow along a long prismatic granular bed, with rectangular cross section, with mass transfer from a rectangular piece of the pavement. This is the work we plan to carry out in the lab, but it will be also necessary to adapt ( i. e., to do again) all the analytical/computational work for this geometry.
One additional feature of the project will be to start studying the applicability of our method to the analysis of the corrosion by acidic waters of buried limestone columns and walls. |