Experimental and numerical investigation of axialand tangential forces in a stirred tank with yield-stress fluids

• Autorzy: Story Anna , Story Grzegorz , Jaworski Zdzisław

Identyfikatory

DOI

10.24425/cpe.2021.138923

• Języki publikacji: EN

Abstrakty

EN

Complex rheological properties of yield-stress materials may lead to the generation of an intensive mixing zone near a rotating impeller. From the practical point of view, the zone should cover most of the stirred liquid. According to the literature review, several parameters may affect the size of the mixing zone, in particular forces exerted on the liquid. This paper presents both experimental and numerical investigation of axial and tangential forces generated during mechanical mixing of yield-stress fluids in a stirred tank. The tested fluids were aqueous solutions of Carbopol Ultrez 30 of concentration either 0.2 or 0.6 wt% and pH = 5.0. The study was performed for three types of impeller, pitched blade turbine, Prochem Maxflo T and Rushton turbine, in a broad range of their rotational speed, 𝑁 = 60 − 900 rpm. The axial and tangential forces were calculated from the apparent mass of the stirred tank and torque, respectively. The experimental results were compared with CFD predictions, revealing their good agreement. Analysis of the generated forces showed that they are dependent on the rheological characteristic of liquid and the impeller type. It was also found that although axial force was smaller than tangential force, it significantly increased the resultant force.

Słowa kluczowe

EN

mixing; yield-stress fluid; axial force; tangential force; CFD

PL

mieszanie; płyn do granicy plastyczności; siła osiowa; siła styczna; CFD

• Wydawca: Komitet Inżynierii Chemicznej i Procesowej Polskiej Akademii Nauk
• Czasopismo: Chemical and Process Engineering
• Rocznik: 2021
• Tom: Vol. 42, nr 2
• Strony: 173–--190
• Opis fizyczny: Bibliogr. 39 poz.

Twórcy

autor

Story Anna

• West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical and Process Engineering, al. Piastów 42, 71-065 Szczecin, Poland

autor

Story Grzegorz

• West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical and Process Engineering, al. Piastów 42, 71-065 Szczecin, Poland

autor

Jaworski Zdzisław

• West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical and Process Engineering, al. Piastów 42, 71-065 Szczecin, Poland

Bibliografia

• 1. Adams L. W., Barigou M., 2007. CFD analysis of caverns and pseudo-caverns developed during mixing of non Newtonian fluids. Chem. Eng. Res. Des., 85, 598–604. DOI: 10.1205/cherd06170.
• 2. Amanullah A., Hjorth S.A., Nienow A.W., 1997. Cavern sizes generated in highly shear thinning viscous fluids by SCABA 3SHP1 impellers. Food Bioprod. Process., 75, 232–238. DOI: 10.1205/096030897531630.
• 3. Amanullah A., Hjorth S.A., Nienow A.W., 1998. A new mathematical model to predict cavern diameters in highly shear thinning, power law liquids using axial flow impellers. Chem. Eng. Sci., 53, 455–469. DOI: 10.1016/S0009-2509(97)00200-5.
• 4. Ameur H., 2016. Agitation of yield stress fluids in different vessel shapes. Eng. Sci. Technol., 19, 189–196. DOI: 10.1016/j.jestch.2015.06.007.
• 5. Ameur H., 2017. Mixing of a viscoplastic fluid in cylindrical vessels equipped with paddle impellers. Chemistry Select, 2, 11492–11496. DOI: 10.1002/slct.201702459.
• 6. Ameur H., 2019. Some modifications in the Scaba 6SRGT impeller to enhance the mixing characteristics of Hershel-Bulkley fluids. Food Bioprod. Process., 117, 302–309. DOI: 10.1016/j.fbp.2019.08.007.
• 7. Ameur H., Bouzit M., Helmaoui M., 2011. Numerical study of fluid flow and power consumption in a stirred vessel with a Scaba 6SRGT impeller. Chem. Process Eng., 32, 351–366. DOI: 10.2478/v10176-011-0028-0.
• 8. Arratia P.E., Kukura J., Lacombe J., Muzzio F.J., 2006. Mixing of shear-thinning fluids with yield stress in stirred tanks. AIChE J., 52, 2310–2322. DOI: 10.1002/aic.10847.
• 9. Bakker C.W., Meyer C.J., Deglon D.A., 2009. Numerical modelling of non-Newtonian slurry in a mechanical flotation cell. Miner. Eng., 22, 944–950. DOI: 10.1016/j.mineng.2009.03.016.
• 10. Bakker C.W., Meyer C.J., Deglon D.A., 2010. The development of a cavern model for mechanical flotation cells. Miner. Eng., 23, 968–972. DOI: 10.1016/j.mineng.2010.03.016.
• 11. Bhole M.R., Bennington C.P.J., 2010. Performance of four axial flow impellers for agitation of pulp suspensions in a laboratory-scale cylindrical stock chest. Ind. Eng. Chem. Res., 49, 4444-4451. DOI: 10.1021/ie901854d.
• 12. Bhole M.R., Hui L.K., Gomez C., Bennington C.P.J., Dumont G.A., 2011. The effect of off-wall clearance of a side-entering impeller on the mixing of pulp suspensions in a cylindrical stock chest. Can. J. Chem. Eng., 89, 985–995. DOI: 10.1002/cjce.20503.
• 13. Bonn D., Denn M.M., Berthier L., Divoux T., Manneville S., 2017. Yield stress materials in soft condensed matter. Rev. Mod. Phys., 89, 035005, 1–40. DOI: 10.1103/RevModPhys.89.035005.
• 14. del Pozo D.F., Line A., Van Geem K.M., Le Men C., Nopens I., 2020. Hydrodynamic analysis of an axial impeller in a non-Newtonian fluid through particle image velocimetry. AIChE J., 66, e16939, 1–16. DOI: 10.1002/aic.16939.
• 15. Dylak A., Jaworski Z., 2015. A CFD study of formation of the intensive mixing zone in a highly non-Newtonian fluid. AIP Conference Proceedings, 1648, 030013. DOI: 10.1063/1.4912330.
• 16. Ford C., Ein-Mozaffari F., Bennington C.P.J., Taghipour F., 2006. Simulation of mixing dynamics in agitated pulp stock chests using CFD. AIChE J., 52, 3562–3569. DOI: 10.1002/aic.10958.
• 17. Fořt I., Seichter P., Pešl L., 2013. Axial thrust of axial flow impellers. Chem. Eng. Res. Des., 91, 789–794. DOI: 10.1016/j.cherd.2012.10.001.
• 18. Frigaard I. A., Nouar C., 2005. On the usage of viscosity regularisation methods for visco-plastic fluid flow computation. J. Non-Newtonian Fluid Mech., 127, 1-26. DOI: 10.1016/j.jnnfm.2005.01.003.
• 19. Galindo E., Arguello M., Velasco D.A., Albiter V., Martinez A., 1996. A comparison of cavern development in mix ing a yield stress fluid by Rushton and intermig impellers. Chem. Eng. Technol., 19, 315–323. DOI: 10.1002/ceat.270190405.
• 20. Galindo E., Nienow A.W., 1992. Mixing of highly viscous simulated Xanthan fermentation broths with the Lightinin A-315-impeller. Biotechnol. Prog., 8, 233–239. DOI: 10.1021/bp00015a009.
• 21. Herschel W. H., Bulkley R., 1926. Consistency measurements of rubber-benzol solutions. Kolloid-Zeitschrift, 39, 291–300. DOI: 10.1007/BF01432034.
• 22. Hui L.K., Bennington C.P.J., Dumont G.A., 2009. Cavern formation in pulp suspensions using side-entering axial-flow impellers. Chem. Eng. Sci., 64, 509–519. DOI: 10.1016/j.ces.2008.09.021.
• 23. Jaworski Z., Nienow A.W., 1994. LDA measurements of flow fields with hydrofoil impellers in fluids with different rheological properties. Eighth European Conference on Mixing, IChemE Symp. Series, 136, 105–112.
• 24. Jaworski Z., Spychaj T., Story A., Story G., 2021. Carbomer microgels as model yield-stress fluids. Rev. Chem. Eng., 000010151520200016. DOI: 10.1515/revce-2020-0016.
• 25. Kelly W., Gigas B., 2003. Using CFD to predict the behavior of power law fluids near axial-flow impellers operating in the transitional flow regime. Chem. Eng. Sci., 58, 2141–2152. DOI: 10.1016/S0009-2509(03)00060-5.
• 26. Nienow A.W., Elson T.P., 1988. Aspects of mixing in rheologically complex fluids. Chem. Eng. Res. Des., 66, 5–15.
• 27. Rodriguez B.E., Wolfe M.S., Fryd M., 1994. Nonuniform swelling of alkali swellable microgels. Macromolecules, 27, 6642–6647. DOI: 10.1021/ma00100a058.
• 28. Russell A.W., Kahouadji L., Mirpuri K., Quarmby A., Piccione P.M., Matar O.K., Luckham P.F., Markides C.N., 2019. Mixing viscoplastic fluids in stirred vessels over multiple scales: A combined experimental and CFD approach. Chem. Eng. Sci., 208, 115129. DOI: 10.1016/j.ces.2019.07.047.
• 29. Savreux F., Jay P., Magnin A., 2007. Viscoplastic fluid mixing in a rotating tank. Chem. Eng. Sci., 62, 2290–2301. DOI: 10.1016/j.ces.2007.01.020.
• 30. Simmons M.J.H., Edwards I., Hall J.F., Fan X., Parker D.J., Stitt E.H., 2009. Techniques for visualization of cavern boundaries in opaque industrial mixing systems. AIChE J., 55, 2765–2772. DOI: 10.1002/aic.11889.
• 31. Sossa-Echeverria J., Taghipour F., 2014. Effect of mixer geometry and operating conditions on flow mixing of shear thinning fluids with yield stress. AIChE J., 60, 1156–1167. DOI: 10.1002/aic.14309.
• 32. Sossa-Echeverria J., Taghipour F., 2015. Computational simulation of mixing flow of shear thinning non-Newtonian fluids with various impellers in a stirred tank. Chem. Eng. Process., 93, 66–78. DOI: 10.1016/j.cep.2015.04.009.
• 33. Story A., Jaworski Z., 2017. A new model of cavern diameter based on a validated CFD study on stirring of a highly shear-thinning fluid. Chem. Pap., 71, 1255–1269. DOI: 10.1007/s11696-016-0119-y.
• 34. Story A., Jaworski Z., Major-Godlewska M., Story G., 2018. Influence of rheological properties of stirred liquids on the axial and tangential forces in a vessel with a PMT impeller. Chem. Eng. Res. Des., 138, 398–404. DOI: 10.1016/j.cherd.2018.09.006.
• 35. Story A., Story G., Jaworski Z., 2020. Effect of carbomer microgel pH and concentration on the Herschel–Bulkley parameters. Chem. Process Eng., 41, 173–182. DOI: 10.24425/cpe.2020.132540.
• 36. Stręk F., 1981. Mieszanie i mieszalniki. Wydawnictwa Naukowo-Techniczne, Warszawa.
• 37. Wichterle K., Wein O., 1975. Agitation of concentrated suspensions. CHISA ’75, Paper B.4.6. Prague, Czechoslo vakia.
• 38. Wu J., Pullum L., 2000. Performance analysis of axial-flow mixing impellers. AIChE J., 46, 489–498. DOI: 10.1002/aic.690460307.
• 39. Xiao Q., Yang N., Zhu J. H., Guo L.J., 2014. Modeling of cavern formation in yield stress fluids in stirred tanks. AIChE J., 60, 3057–3070. DOI: 10.1002/aic.14470