Hartig, J. H., Hannah C.; Stelmach, Tanner J.; Weimer, Alan W. "DEM modeling of fine powder convection in a continuous vibrating bed reactor," Powder Technology Vol. 386, 2021, pp. 209-220. https://doi.org/10.1016/j.powtec.2021.03.038. (https://www.sciencedirect.com/science/article/pii/S0032591021002291)
Abstract: Continuous vibrating spatial particle ALD reactors were developed to achieve high powder throughput while minimizing reactor footprint. Unlike fluidized bed reactors, continuous vibrating spatial particle ALD reactors operate below fluidization, using linear vibration to convey particles through alternating regions of precursor gas. Fine powder convection in these vibrating bed reactors is still not well understood, so cohesive discrete-element-method (DEM) simulations were performed to investigate the solids flow behavior. Using a Fast Fourier Transform (FFT) algorithm, we constructed a sum-of-sines model for the reactor kinematics based on accelerometer data. Accelerometer results and DEM simulations revealed the role of high-frequency excitations and need for backsliding and sticking avoidance in horizontal conveyors at low-g accelerations. From these observations, we propose a novel sawtooth excitation to enable convection of cohesive fine powders at low flow velocities. The model results were compared to data from an in-house continuous vibrating spatial particle ALD reactor.
Keywords: Cohesive powders; Discrete element simulation; Atomic layer deposition; Fast fourier transform; Vibrating system