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An experimental study of pulsing flow in trickle beds is presented, based on data from two measuring techniques. New evidence on pulse arrangement and propagation in the bed, and data on basic pulse characteristics (frequency, celerity,... more
An experimental study of pulsing flow in trickle beds is presented, based on data from two measuring techniques. New evidence on pulse arrangement and propagation in the bed, and data on basic pulse characteristics (frequency, celerity, length, duration) as well as liquid holdup and pressure drop measurements are included. Some of these data, such as the length of the liquid-rich zone of pulses, are not currently available. Two flow regions exhibit different trends of pulse characteristics, “mild” and “wild” pulsing for relatively small and large liquid flow rates, respectively. New findings are compared with previously available data and correlations. An effort to develop new or modify existing generalized correlations is made for the aforementioned quantities.
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Experimental results are reported on simulataneous heat transfer and gas dissolution during the direct-contact condensation of steam on water in the presence of CO2. A column filled with structured packing is used as condenser with the... more
Experimental results are reported on simulataneous heat transfer and gas dissolution during the direct-contact condensation of steam on water in the presence of CO2. A column filled with structured packing is used as condenser with the water in counterflow with the steam/CO2 mixture. The region along the column where the bulk of condensation takes place is controllable by suitable choice of the steam/water ratio. Measured local heat-transfer coefficients change by roughly an order of magnitude from the bottom to the top of the column. The extent of CO2 dissolution in the water/condensate under most conditions is unexpectedly high and depends strongly on the exit liquid temperature. A driving force based on the interfacial CO2 concentration, not the overall concentration difference used in conventional absorption operations, is suggested as more appropriate to describe the phenomenon. The data are complemented with preliminary results from a computational model based on the integration along the column of local heat- and mass-transfer rates.
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The quest for advanced models to realistically simulate various processes involving populations of “particles” (aerosols, dispersions of all kinds, minerals, cultures of microorganisms) necessitates the extension of the classical... more
The quest for advanced models to realistically simulate various processes involving populations of “particles” (aerosols, dispersions of all kinds, minerals, cultures of microorganisms) necessitates the extension of the classical population balance formulation, which is of zero dimension (lumped) in external and one-dimensional (1-D) (single particle-characterization variable) in internal coordinate space, to more dimensions in both spaces. In order to contribute in this direction, this work is focused on a spatially distributed fragmentation equation, the spatial nonuniformity being governed by a diffusion mechanism and by deposition of particles on solid boundaries. The combined effect of diffusion and fragmentation on the particle-size distribution is of interest here. The linear form of the fragmentation-diffusion equation allows a convenient analytical manipulation, based on decomposition of solutions in spatial and temporal modes. Generalized solutions are derived for the above equation for arbitrary spatial domains, fragmentation functions, deposition rates and particle sources. The above approach can be combined with the well-known approaches for the numerical solution of the lumped fragmentation equation to derive solutions for the fragmentation-diffusion equation under arbitrary conditions. This study, as a first step, is restricted to obtaining explicit results for some rather simple cases, for example, power law fragmentation and deposition rates, fragmentation in equal sizes and simple shapes of the domain under consideration. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1746–1759, 2004
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Research Interests: Food Engineering, Food, Scanning Electron Microscopy, Atomic Force Microscopy, Silica, and 19 moreDiamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer(Diamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer)
(Diamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer)
Research Interests: Food Engineering, Food, Scanning Electron Microscopy, Atomic Force Microscopy, Silica, and 19 moreDiamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer(Diamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer)
(Diamond Like Carbon, Stainless Steel, Surface topography, Contact angle, Ion Implantation, Calcium Phosphate, Bacillus subtilis, Surface Tension, Surface Properties, Dairy Products, Bacillus Cereus, Surface characterization, Food Sciences, Whey Protein, Chemical Composition, X Ray Photoelectron Spectroscopy, Aqueous Solution, Bacterial Adhesion, and Thin Layer)