TY - JOUR
T1 - Sound assisted fluidization of nanoparticle agglomerates
AU - Zhu, Chao
AU - Liu, Guangliang
AU - Yu, Qun
AU - Pfeffer, Robert
AU - Dave, Rajesh N.
AU - Nam, Caroline H.
N1 - Funding Information: We would like to acknowledge the National Science Foundation for financial support through Grant #0210400, NIRT-Collaborative Research: Experimental and Computational Investigations of Fluid Interactions/Transport in Nanodomains and Around Nanoparticles. We would also like to express our appreciation to Dr. Herbert Riemenschneider and Mr. Jonah Klein of Degussa-Huls for supplying us with nanoparticles.
PY - 2004/3/18
Y1 - 2004/3/18
N2 - This paper presents some preliminary observations on sound-assisted fluidization of hydrophobic fumed silica nanoparticles (Degussa Aerosil® R974, having a primary particle size of 12 nm) in the form of large 100-400 μm agglomerates. The effect of sound on the fluidization behavior of the nanoparticle agglomerates, including the fluidization regime, the minimum fluidization velocity, the bed pressure drop and the bed expansion has been investigated. It is shown that, with the aid of sound wave excitation at low frequencies, the bed of nanoparticle agglomerates can be readily fluidized and the minimum fluidization velocity is significantly reduced. For example, the minimum fluidization velocity is decreased from 0.14 cm/s in the absence of sound excitation to 0.054 cm/s with the assistance of the sound. In addition, under the influence of sound, channeling or slugging of the bed quickly disappears and the bed expands uniformly. Within a certain range of the sound frequency, typically from 200 to 600 Hz, bubbling fluidization occurs. Both the bed expansion and the bubble characteristics are strongly dependent on the sound frequency and sound pressure level. However, sound has almost no impact on the fluidization, when the sound frequency is extremely high, above 2000 Hz. A relatively high sound pressure level (such as 115 dB) is needed to initiate the fluidization.
AB - This paper presents some preliminary observations on sound-assisted fluidization of hydrophobic fumed silica nanoparticles (Degussa Aerosil® R974, having a primary particle size of 12 nm) in the form of large 100-400 μm agglomerates. The effect of sound on the fluidization behavior of the nanoparticle agglomerates, including the fluidization regime, the minimum fluidization velocity, the bed pressure drop and the bed expansion has been investigated. It is shown that, with the aid of sound wave excitation at low frequencies, the bed of nanoparticle agglomerates can be readily fluidized and the minimum fluidization velocity is significantly reduced. For example, the minimum fluidization velocity is decreased from 0.14 cm/s in the absence of sound excitation to 0.054 cm/s with the assistance of the sound. In addition, under the influence of sound, channeling or slugging of the bed quickly disappears and the bed expands uniformly. Within a certain range of the sound frequency, typically from 200 to 600 Hz, bubbling fluidization occurs. Both the bed expansion and the bubble characteristics are strongly dependent on the sound frequency and sound pressure level. However, sound has almost no impact on the fluidization, when the sound frequency is extremely high, above 2000 Hz. A relatively high sound pressure level (such as 115 dB) is needed to initiate the fluidization.
KW - Agglomerate
KW - Fluidization
KW - Nanoparticles
KW - Sound waves
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U2 - https://doi.org/10.1016/j.powtec.2004.01.023
DO - https://doi.org/10.1016/j.powtec.2004.01.023
M3 - Article
SN - 0032-5910
VL - 141
SP - 119
EP - 123
JO - Powder Technology
JF - Powder Technology
IS - 1-2
ER -