CFD method for evaluation of critical impeller speed required for floating particles suspension

Łukasz Kacperski,

Joanna Karcz

Abstrakt

In the paper, critical impeller speeds were analyzed on the basis of the performed simulations of the concentration distribution of the floating particles suspension in an agitated vessel, equipped with pitched blade turbine. The required range of the standard deviation of the local particles concentration in a suspension was assumed as comparative criterion. The results obtained from numerical computations were compared with the values of the critical impeller speeds determined experimentally.

Słowa kluczowe: CFD method, suspension of floating particles, critical impeller speed
References

Stręk F., Mieszanie i mieszalniki, WNT, Warsaw 1981.

Kamieński J., Mieszanie układów wielofazowych, WNT, Warsaw 2004.

Etchells A.W., Mixing of floating solids, Plenary Lecture, 4th Intern. Symp. on Mixing in Industrial Processes ISMIP 4, Toulouse, France, 14‒16.05.2001.

Ozcan-Taskin G., Wei H., The effect of impeller-to-tank diameter ratio on draw down of solids, Chem. Eng. Sci., vol. 58, 2003, 2011-2022.

Karcz J., Mackiewicz B., Suspending of floating solids in an agitated vessel, Chem. Proc. Eng., vol. 27, 2006, 1517-1533.

Karcz J., Mackiewicz B., An effect of particles wettability on the draw down of floating solids in a baffled agitated vessel equipped with a high-speed impeller, Chem. Proc. Eng., vol. 28, 2007, 661-672.

Mackiewicz B., PhD Thesis, Szczecin University of Technology, 2008.

Karcz J., Mackiewicz B., Effects of vessel baffling on the drawdown of floating solids, Chem. Pap., vol. 63(2), 2009, 164-171.

Ozcan-Taskin G., Effect of scale on the draw down of solids, Chem. Eng. Sci., vol. 61, 2006, 2871-2879.

Murthy B.N., Ghadge R.S., Joshi J.B., CFD simulation of gas-liquid-solid stirred reactor: Prediction of critical impeller speed for solid suspension, Chem. Eng. Sci., vol. 62, 2007, 7184-7195.

Mackiewicz B., Karcz J., CFD modelling of suspension of floating particles, Chem. Proc. Eng., vol. 30, 2009, 111-123.

Cekinski E., Giuletti M., Seckler M.M., A new approach to characterize suspensions in stirred vessel based on computational fluid dynamics, Brazilian Journal of Chemical Engineering, vol. 27(2), 2010, 265-273.

Tamburini A., Cipollina A., Micale G., CFD simulation of solid – liquid suspension in baffled stirred tans below complete suspension speed, Chem. Eng. Trans., vol. 24, 2011, 1435-1440.

Karcz J., Kacperski Ł., Bitenc M., Domański M., An application of computational fluid dynamics method to localization of regions of varied mixing intensity in mechanically agitated suspension of floating solids (in Polish), Przemysł Chemiczny, vol. 90(9), 2011, 1647-1650.

Karcz J., Kacperski Ł., An effect of grid quality on the results of numerical simulations of the fluid flow in an agitated vessel, 14th European Conference on Mixing, Warsaw, Poland, 1‒13.09.2012, 205-210.

Kacperski ł., Karcz J., Numeryczna analiza rozkładu stężenia cząstek lekkich w zawiesinie mieszanej mechanicznie, Inż. i Ap. Chem., vol. 52(4), 2013, 328-329.

ANSYS CFX-Solver modeling guide, ANSYS Inc., Release 13.0, November 2010.