Mixing power and hydrodynamics for different clearances of the flat blade turbine impeller

• Autorzy: Stelmach Jacek

Identyfikatory

DOI

10.24425/cpe.2023.144693

• Języki publikacji: EN

Abstrakty

EN

In the paper, the mixing power and distributions of velocity and velocity pulsations in a baffled stirred tank with a flat blade turbine impeller placed at different distances from the bottom were determined. It was found that the mixing power reaches minimum values when the relative clearance of the impeller is C/D = 0.6÷0.7. The investigations of velocity distributions using the PIV method showed the axial flow of the liquid through the impeller. This results in deviations from the typical radial-circumferential flow and changes in mixing power vs. impeller clearance versus a Rushton impeller. With a clearance corresponding to the minimum power, the flow is axial-circumferential with one circulation loop. For a flat blade turbine impeller, good mixing conditions are obtained for a clearance of 0.8 < C/D < 0.9.

Słowa kluczowe

EN

flat blade turbine impeller (FBT); mixing power; velocity distributions; velocity pulsation distributions

PL

wirnik turbiny z płaskimi łopatkami (FBT); moc mieszania; rozkład prędkości; rozkład pulsacji prędkości

• Wydawca: Komitet Inżynierii Chemicznej i Procesowej Polskiej Akademii Nauk
• Czasopismo: Chemical and Process Engineering : New Frontiers
• Rocznik: 2023
• Tom: Vol. 44, nr 2
• Strony: art. no. e7
• Opis fizyczny: Bibliogr. 29 poz., rys.

Twórcy

autor

Stelmach Jacek

• Lodz University of Technology, Faculty of Process and Environmental Engineering, Wolczanska 213, 93-005 Lodz, Poland

• https://orcid.org/0000-0001-9348-5315

Bibliografia

• 1. Armenante P.M., Nagamine E.U., 1998. Effect of low off-bottom impeller clearance on the minimum agitation speed for complete suspension of solids in stirred tanks. Chem. Eng. Sci., 53, 1757–1775. DOI: 10.1016/S0009-2509(98)00001-3.
• 2. Baldi S., Hann D., Yianneskis M., 2002. On the measurements ofturbulence energy dissipation in stirred vessels with PIV techniques. Proceedings of the 10th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.
• 3. Baldi S., Yianneskis M., 2003. On the direct measurement ofturbulence energy dissipation in stirred vessels with PIV. Ind. Eng. Chem. Res., 42, 7006–7016. DOI: 10.1021/ie0208265.
• 4. de Jong J., Cao L., Woodward S.H., Salazar J.P.L.C., Collins L.R., Meng H., 2009. Dissipation rate estimation from PIV in zero-mean isotropic turbulence. Experiments in Fluid, 46, 499–515. DOI: 10.1007/s00348-008-0576-3.
• 5. Delafosse A., Collignon M.-L., Crine M., Toye D., 2011. Estimation of the turbulent kinetic energy dissipation rate from 2D-PIV measurements in a vessel stirred by an axial Mixel TTP impeller. Chem. Eng. Sci., 66, 1728–1737. DOI: 10.1016/j.ces.2011.01.011.
• 6. Devarajulu C., Loganathan M., 2016. Effect of impeller clearance and liquid level on critical impeller speed in an agitated vessel using different axial and radial impellers. J. Appl. Fluid Mech., 9, 2753-2761. DOI: 10.29252/jafm.09.06.24824.
• 7. Gray D.J., 1987. Impeller clearance effect on off bottom particlesuspension in agitated vessels. Chem. Eng. Commun., 61, 151–158. DOI: 10.1080/00986448708912035.
• 8. Heim A., Stelmach J., 2011. The comparison of velocities at the self-aspirating disk impeller level. Przemysł Chemiczny, 90/9, 1642–1646.
• 9. Kilander J., Rasmuson A., 2005. Energy dissipation and macro instabilities in a stirred square tank investigated using an LE PIV approach and LDA measurements. Chem. Eng. Sci., 60, 6844–6856. DOI: 10.1016/j.ces.2005.02.076.
• 10. Kresta S., 1998. Turbulence in stirred tanks: Anisotropic, approximate, and applied. Can. J. Chem. Eng., 76, 563–576. DOI:10.1002/cjce.5450760329.
• 11. Micheletti M., Baldi S., Yeoh S.L., Ducci A., Papadakis G., Lee K.C., Yianneskis M., 2004. On spatial and temporal variations and estimates of energy dissipation in stirred reactors.Chem. Eng. Res. Des., 82, 1188–1198. DOI: 10.1205/cerd.82.9.1188.44172.
• 12. Nagata S., 1975. Mixing. Principles and applications. John Wiley & Sons, New York, NY, USA.
• 13. Ng K., Yianneskis M., 2000. Observations on the distribution of energy dissipation in stirred vessels. Chem. Eng. Res. Des., 78, 334–341. DOI: 10.1205/026387600527446.
• 14. Raffel M., Willert C., Wereley S., Kompenhans J., 2007. Particle image velocimetry. A practical guide. 2nd edition, Springer Berlin, Heidelberg. Rieger F., Moravec J., Stelmach J., Kuncewicz Cz., 2021. Effect of modification of the stirrer with folding blades on the increase in mixing power during emptying the tank. Przemysł Chemiczny, 100/12, 1231–1235. DOI: 10.15199/62.2021.12.15.
• 15. Saarenrinne P., Piirto M., 2000. Turbulent kinetic energy dissipation rate estimation from PIV vector fields. Exp. Fluids, 29 (Suppl 1), S300–S307. DOI: 10.1007/s003480070032.
• 16. Sharp K.V., Kim K.C., Adrian R., 1998. Dissipation estimation around a Rushton turbine using particle image velocimetry. Proceedings of the 9th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.
• 17. Sheng J., Meng H., Fox R.O., 2000. A large eddy PIV method for turbulence dissipation rate estimation. Chem. Eng. Sci., 55, 4423–4434. DOI: 10.1016/S0009-2509(00)00039-7.
• 18. Skalski M., 2021. Investigation of the dependence of the mixing power on the distance between the impeller and the bottom of the tank. Eng. Thesis, Lodz University of Technology, Lodz, Poland (in Polish).
• 19. Stelmach J., Kuncewicz Cz., Rieger F., Moravec J., Jirout T., 2020. Increase of mixing power during emptying of tanks with turbine-blade impellers. Przemysł Chemiczny, 99/2, 239–243. DOI: 10.15199/62.2020.2.11.
• 20. Stelmach J., Kurasiński T., Kuncewicz Cz., 2005. Comparative analysis of selected methods for calculation of energy dissipation rate. Chem. Process Eng., 26, 201–215.
• 21. Stelmach J., Musoski R., Kuncewicz Cz., Głogowski M., 2019. Turbulent energy dissipation rate and turbulence scales in the blade region of a self-aspirating disk impeller. J. Appl. Fluid Mech., 12, 715–728. DOI: 10.29252/jafm.12.03.28836.
• 22. Stelmach J., Musoski R., Kuncewicz Cz., Jirout T., Rieger F., 2022. Efficiency of PBT impellers with different blade cross-sections. Energies, 15, 585. DOI: 10.3390/en15020585.
• 23. Stelmach J., Musoski R., Mysakowski T., 2021. Analysis of the efficiency of PBT stirrers depending on the clearance. Przemysł Chemiczny, 100/8, 762–766. DOI: 10.15199/62.2021.8.8.
• 24. Stręk F., 1975. Mixing and stirrers. Chemistry, Leningrad.
• 25. Stręk F., 1981. Mieszanie i mieszalniki. WNT, Warszawa.
• 26. Šulc R., Ditl P., 2017. Local turbulent energy dissipation rate in an agitated vessel: New approach to dimensionless definition. Theor. Found. Chem. Eng., 51, 159–174. DOI: 10.1134/S0040579517020105.
• 27. Tanaka T., Eaton J.K., 2007. A correction method for measuring turbulence kinetic energy dissipation rate by PIV. Exp. Fluids,42, 893–902. DOI: 10.1007/s00348-007-0298-y.
• 28. Zhou G., Kresta S.M., 1996a. Distribution of energy between nconvective and turbulent flow for three frequently used impellers. Chem. Eng. Res. Des., 74, 379–389.
• 29. Zhou G., Kresta S.M., 1996b. Impact of tank geometry on the maximum turbulence energy dissipation rate for impellers. AIChE J., 42, 2476–2490. DOI: 10.1002/aic.690

Uwagi

Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023).