Dinal Perera will present his Master's Thesis Defense
- Monday, November 13, 2017 at 2:10pm
- Wilson Hall, Room 1-122 - view map
Heat Transfer and Flow in Packed Beds with Experimental NMR Microscopy and Computational Fluid Dynamics
Fluid flow and heat transfer characteristics in packed beds are studied extensively due to its importance in different fields. Packed beds are hollow vessels that are filled with packing material to form a porous medium, which are used in various industries ranging from the pharmaceutical industry to the energy industry. Experimental methods that study flow and heat transfer in packed beds use invasive techniques that perturb the flow and hence the heat transfer of the liquid and solid phase. In addition, model validation through numerical methods has been a challenging task. This thesis presents a novel method that utilizes NMR techniques to map the heat transfer processes and velocities within packed beds, non-invasively. The increase in signal intensities is captured by 1H imaging using a dual tune coil which is coupled with 19F imaging to map the velocity profile of a Fluorine-rich liquid phase. These experimental conditions inform CFD models generated by coupling Discrete Element Modelling (DEM) with CFD. DEM allows the generation of randomly packed beds that mimic packed beds used in experimental work.
Both experimental and CFD models yielded maximum velocities in the range of 6 mm/s to 8 mm/s, while showing important attributes such as intra-particle melt gradients, preferential flow pathways and channeling effect. Experimental work show a melt front of 60 mm in 41 minutes while models yielded a slower melt front. In modelling the beds, the effects of particle size and geometry on flow, heat transfer and pore structure are explored.
- Department of Mechanical & Industrial Engineering