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Intel ISEF 2013 Finalist Profile

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The Sortation of Granular Materials through Forced Convection: Comparing Simulation and Experiment

Seneca Velling
Zachary Collins

Watchung Hills Regional High School, Warren, NJ

Understanding of the transport of complex fluids, such as granular-gas or droplet-gas mixtures is important for the transport of materials and fuel in both normal and varied gravity environments. We combined a computer simulation and experiment to model the flow of a granular mixture in a pipe. The experimental system consisted of a transparent cylinder containing a mixture of 0.3 - 1.4 mm plastic beads and air. The beads were fluidised by air injected upward. The motion of the bead-air mixture was video recorded at varying air speeds in the range of 0.75 - 1.5 m/s. The air flow was laminar with visible wall drag as per video obtained using smoke sticks. The video analysis using Logger Pro showed distinct sorting by size with the beads in the top &#8531; portion of the mixture 1.4 ± 0.2 times larger than the beads in the lower portion of the container. The video showed the smaller beads circulating in the vertical plane while the top layer of the larger beads remained relatively steady. The tracking of individual beads showed small oscillations in vertical plane at a frequency of 2.4 ± 0.8 Hz. To understand the theoretical basis of the observed motion we ran a computational fluid-dynamics simulation using the GNU OpenFoam package, under Gnu Public License. Using C++ we were able to set airspeed as a variable and to enter the geometry of our experimental system. To be able to run this computationally intensive program in real time we created a computer cluster. The cluster was designed to distribute the processing in parallel through a series of slave nodes. Visualization Tool Kit was used to represent the output files. The results of our simulation support our experimental observations. The use of our simulation to model the pipe-constrained fluidization of grains allows us t

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