TY - JOUR
T1 - Experimental investigation on air bubble dynamics during fine powder discharge in a silo
AU - Sheng, Li Tsung
AU - Hsiau, Shu San
AU - Wen, Chun Yu
N1 - Publisher Copyright:
© 2021 The Society of Powder Technology Japan
PY - 2021/1
Y1 - 2021/1
N2 - An unstable discharge rate occurs during dry fine powder discharge from a silo due to significant two–phase solid/gas interactions that occur in powder flows. In addition, the air bubble phenomenon may occur in a silo during fine powder discharge. The bubble dynamics seriously influence the fine powder discharge stability in the silo. Therefore, for some industrial applications with silo discharge of fine material, it is important to understand it. In this study, we experimentally investigate the effect of air bubbles on fine powder discharge behavior, including the discharge mass flow rate and variation in pressure inside the silo. An initial collapse of the powder bed in the silo is observed at the beginning of the discharge process, causing the pressure to change rapidly. Moreover, the dependence of the bubble size, bubble rising velocity, number of bubbles, and frequency of bubble generation on the size of the fine powder are analyzed in detail. The air–loss index for different particle sizes is calculated to investigate the proportion of the air flowing into the silo that disperses into the voids between the powders and does not become part of a bubble. The bubble properties in the experimental cases that use different particle sizes are consistent with the Geldart particle classification of the used powders. The results of this study successfully illustrate the bubble dynamics and the discharge behavior of fine powder.
AB - An unstable discharge rate occurs during dry fine powder discharge from a silo due to significant two–phase solid/gas interactions that occur in powder flows. In addition, the air bubble phenomenon may occur in a silo during fine powder discharge. The bubble dynamics seriously influence the fine powder discharge stability in the silo. Therefore, for some industrial applications with silo discharge of fine material, it is important to understand it. In this study, we experimentally investigate the effect of air bubbles on fine powder discharge behavior, including the discharge mass flow rate and variation in pressure inside the silo. An initial collapse of the powder bed in the silo is observed at the beginning of the discharge process, causing the pressure to change rapidly. Moreover, the dependence of the bubble size, bubble rising velocity, number of bubbles, and frequency of bubble generation on the size of the fine powder are analyzed in detail. The air–loss index for different particle sizes is calculated to investigate the proportion of the air flowing into the silo that disperses into the voids between the powders and does not become part of a bubble. The bubble properties in the experimental cases that use different particle sizes are consistent with the Geldart particle classification of the used powders. The results of this study successfully illustrate the bubble dynamics and the discharge behavior of fine powder.
KW - Air bubble
KW - Fine powder discharge
KW - Silo
UR - http://www.scopus.com/inward/record.url?scp=85097463131&partnerID=8YFLogxK
U2 - 10.1016/j.apt.2020.11.021
DO - 10.1016/j.apt.2020.11.021
M3 - 期刊論文
AN - SCOPUS:85097463131
SN - 0921-8831
VL - 32
SP - 106
EP - 120
JO - Advanced Powder Technology
JF - Advanced Powder Technology
IS - 1
ER -