(83a) An Experimental and Computational Study of Vortex Formation in Stirred Tanks
AIChE Spring Meeting and Global Congress on Process Safety
2017
2017 Spring Meeting and 13th Global Congress on Process Safety
20th Topical Conference on Refinery Processing
Advances in Plant Simulation and Design II
Tuesday, March 28, 2017 - 10:15am to 10:45am
In stirred tanks operating under unbaffled conditions, a surface depression, referred to as a âvortexâ, may develop in the stirred medium. It is often of interest to estimate, a priori, the vortex depth as too deep a vortex can lead to issues such as air bubble entrainment into the process fluid, mechanical vibrations of the equipment, and noisy operation. While it is common to characterize vortex depth in terms of an impeller based Froude number alone (Nagata, Mixing: Principles and Applications, 1975), some attempts with limited success have also been made to correlate vortex depth with fluid viscosity. In the present work, we first investigate the Nagataâs inviscid theory and outline the key requirements for a simple Froude number dependence to hold. Specifically, it is shown that the key feature needed for a simple Froude number dependence is presence of a tangential flow and absence of radial and axial flow. Using multiphase flow simulations based on a volume of fluid method in OpenFOAM, we show that precisely this requirement is violated at relatively low Reynolds numbers (Re<104). Experiments are then used to build a new correlation for vortex depth in terms of Froude number, Reynolds number and impeller submergence. Scalability of the correlation is then successfully tested using additional experiments and computer simulations.
Topics
Checkout
This paper has an Extended Abstract file available; you must purchase the conference proceedings to access it.
Do you already own this?
Log In for instructions on accessing this content.
Pricing
Individuals
2017 Spring Meeting and 13th Global Congress on Process Safety
AIChE Pro Members | $150.00 |
AIChE Graduate Student Members | Free |
AIChE Undergraduate Student Members | Free |
AIChE Explorer Members | $225.00 |
Non-Members | $225.00 |
20th Topical Conference on Refinery Processing only
AIChE Pro Members | $100.00 |
Fuels and Petrochemicals Division Members | Free |
AIChE Graduate Student Members | Free |
AIChE Undergraduate Student Members | Free |
AIChE Explorer Members | $150.00 |
Non-Members | $150.00 |