Hysteresis in cloud heights during solid suspension in stirred tank reactor: Experiments and CFD simulations

Madhavi V. Sardeshpande, Vinay A. Juvekar, Vivek V. Ranade*

*Corresponding author for this work

Research output: Contribution to journalArticle

21 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2795-2804
Number of pages10
JournalAIChE Journal
Issue number11
Publication statusPublished - Nov 2010
Externally publishedYes


  • CFD
  • Hysteresis in cloud height
  • Solid velocity profiles

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Biotechnology
  • Environmental Engineering

Fingerprint Dive into the research topics of 'Hysteresis in cloud heights during solid suspension in stirred tank reactor: Experiments and CFD simulations'. Together they form a unique fingerprint.

Cite this