Farzaneh Jalalinejad, Xiaotao T. Bi, John R. Grace, Comparison of theory with experiment for single bubbles in charged fluidized particles, Powder Technology, Available online 17 December 2015, ISSN 0032-5910, http://dx.doi.org/10.1016/j.powtec.2015.12.014.
Abstract: Previous numerical studies, focused on single bubbles, predicted that electrostatics can cause bubble elongation in gas-fluidized beds. However, there was a lack of experimental evidence to test the numerical predictions. This study compares experimental bubble size and shape in beds with two levels of charging. The results indicate that single bubbles are smaller and more elongated in a bed with higher charge density. Instability of bubble roofs for particles of high electrostatic charge density was also observed. The experimental results are in agreement with the previous simulation results, with uniform particle charge density in the lower part of the bed and differences in the upper part. New simulations allowing for spatial variation of charge density show that bubble shape and stability are functions of the particle charge density distribution. Differences between simulation and experimental results are likely due to non-uniform distribution of charge on particles.
Keywords: Electrostatics; Fluidization; Single bubbles; Two fluid model; Computational fluid dynamics