Effect of interparticle forces on the hydrodynamic behaviour of fluidized aerogels

Enhanced fluidization of nanoparticles in an oscillating magnetic field

“…The sieving process serves to separate very large agglomerates, which may have been generated during packing, storage, and transportation. The selection of a mesh opening of 500 m is based on previous experimental findings that the typical size of fluidized nanoparticle agglomerates is between 100 to 400 m [1,2,6,7,12]. The size range of the fluidized nanoparticle agglomerates is measured by analyzing digital images of the fluidized agglomerates with the help of a laser source (Laser Physics Reliant 1000m), a CCD camera (LaVision FlowMaster 3S), and an image processing system (Dual Xeon CPU).…”

“…Models to predict agglomerate size have been proposed for cohesive fine particles 29 and for nanoparticles. 1,5,6,9,14 In vitro measurement of agglomerate sizes by use of SEM and/or particle counters can result in significant errors if the agglomerates are fragile and break easily when they are removed from the fluidized bed and during sample preparation. In a previous article, 6 we proposed an in situ method to measure agglomerate size on the fluidized bed surface by use of an optical system consisting of a laser source, a CCD camera, and an image processing system.…”

“…It has been found that nanoparticles form relatively large agglomerates in order for them to fluidize, [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and the minimum fluidization velocity is relatively high (about several orders of magnitude higher than the minimum fluidization velocity of primary nanoparticles, 1,2,3,4 For certain types of nanoparticles, very smooth fluidization occurs with extremely high-bed expansion, practically no bubbles are observed, and the velocity as a function of voidage around the fluidizing agglomerates obeys the Richardson-Zaki equation. 4,5 This type of fluidization has been called agglomerate particulate fluidization (APF) by Wang et al, 4 and has recently been comprehensively studied by Zhu et al 6 For other types of nanoparticles, fluidization results in a very limited bed expansion, and large bubbles rise up very quickly through the bed.…”

Effect of Temperature on the Nanoparticles Agglomerates Fluidization

“…Two general approaches are represented in the literature, one of them is based on force balance and the other one is based on energy balance. Chaouki et al [6] and Morooka et al [7] were the pioneers of these two categories.…”

Gas Fluidisation of Nano-particle Assemblies: Modified Geldart classification to account for multiple-scale fluidisation of agglomerates and clusters

“…Chaouki et.al. 20) assumes that the drag force due to gas flow, which is approximately equal to gravity force acting on the agglomerate, is equal to the van der Waals force of attraction between the primary particles. Morooka et.al.…”