TY - JOUR
T1 - Hysteresis in cloud heights during solid suspension in stirred tank reactor
T2 - Experiments and CFD simulations
AU - Sardeshpande, Madhavi V.
AU - Juvekar, Vinay A.
AU - Ranade, Vivek V.
PY - 2010/11
Y1 - 2010/11
N2 - Solid suspension in stirred tank reactor is widely used in process industries for catalytic reactions, dissolution of solids, crystallization, and so on. Suspension quality is a key issue in design and operation of stirred reactor and its determination is not straight forward. Cloud height measurements of solid suspension provide a relatively simple way to quantify quality of suspension. In this work, experiments were carried out to quantify variation of cloud heights with impeller speed and particle characteristics. These measurements were carried out using visual observations, image analysis, and ultrasound velocity profiler techniques. The obtained data demonstrated the existence of hysteresis in cloud heights with respect to impeller speed. Apart from possible applications in reducing power required for achieving desired solid suspension quality, the existence of hysteresis also provides a new way to evaluate computational fluid dynamics (CFD) simulations of solid-liquid flows in stirred vessels. An attempt was made to capture observed hysteresis in cloud heights in CFD simulations. The simulated results were compared with the experimental data. The presented models and results (experimental and computational) will be useful for simulating complex solid-liquid flows in stirred reactors.
AB - Solid suspension in stirred tank reactor is widely used in process industries for catalytic reactions, dissolution of solids, crystallization, and so on. Suspension quality is a key issue in design and operation of stirred reactor and its determination is not straight forward. Cloud height measurements of solid suspension provide a relatively simple way to quantify quality of suspension. In this work, experiments were carried out to quantify variation of cloud heights with impeller speed and particle characteristics. These measurements were carried out using visual observations, image analysis, and ultrasound velocity profiler techniques. The obtained data demonstrated the existence of hysteresis in cloud heights with respect to impeller speed. Apart from possible applications in reducing power required for achieving desired solid suspension quality, the existence of hysteresis also provides a new way to evaluate computational fluid dynamics (CFD) simulations of solid-liquid flows in stirred vessels. An attempt was made to capture observed hysteresis in cloud heights in CFD simulations. The simulated results were compared with the experimental data. The presented models and results (experimental and computational) will be useful for simulating complex solid-liquid flows in stirred reactors.
KW - CFD
KW - Hysteresis in cloud height
KW - Solid velocity profiles
UR - http://www.scopus.com/inward/record.url?scp=78650331431&partnerID=8YFLogxK
U2 - 10.1002/aic.12191
DO - 10.1002/aic.12191
M3 - Article
AN - SCOPUS:78650331431
SN - 0001-1541
VL - 56
SP - 2795
EP - 2804
JO - AIChE Journal
JF - AIChE Journal
IS - 11
ER -