© The Institution of Engineering and Technology
An emulsion system was simulated under simple shear rates to analyse its rheological characteristics using the lattice Boltzmann method. The relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, surfactant concentration and droplet size was calculated. The relative viscosity of emulsions decreased with increase in temperature. The shear thinning phenomena explaining the inverse proportion between shear rate and viscosity were observed. An increase in the surfactant concentration caused an increase in the relative viscosity for a decane-in-water emulsion, because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress. An increase in droplet size caused a decrease in the relative viscosity and smaller shear thinning behaviour because of decreased aggregational and repulsive forces within the emulsion system.
References
-
-
1)
-
13. Taghilou, M., Rahimian, M.H.: ‘Lattice Boltzmann model for thermal behavior of a droplet on the solid surface’, Int. J. Thermal Sci., 2014, 86, pp. 1–11 (doi: 10.1016/j.ijthermalsci.2014.06.006).
-
2)
-
16. Zhou, W., Loney, D., Fedorov, A.G., Defertekin, F.L., Rosen, D.W.: ‘Lattice Boltzmann simulations of multiple-droplet interaction dynamics’, Phys. Rev. E, 2014, 89, pp. 033311–1–13 (doi: 10.1103/PhysRevE.89.033311).
-
3)
-
10. Choi, S.B., Lee, J.S.: ‘Film drainage mechanism between two immiscible droplets’. Microfluid Nanofluid, 17, (4), pp. 675–681, 2014 (doi: 10.1007/s10404-014-1379-x).
-
4)
-
19. Guo, Z., Sheng, C., Shi, B.: ‘Discrete lattice effects on the forcing term in the lattice Boltzmann method’, Phys. Rev. E,2002, 65, pp. 046308–1–6.
-
5)
-
15. Skartlien, R., Sollum, E., Akselsen, A., Meakin, P.: ‘Direct numerical simulation of surfactant-stabilized emulsions’, Rheol. Acta, 2012, 51, pp. 649–673 (doi: 10.1007/s00397-012-0628-8).
-
6)
-
21. Guo, Z., Zhao, T.S.: ‘Lattice Boltzmann simulation of natural convection with temperature-dependent viscosity in a porous cavity’, Prog. Comput. Fluid Dyn.,2005, 5, pp. 110–117 (doi: 10.1504/PCFD.2005.005823).
-
7)
-
6. Choi, S.B., Kondaraju, S., Lee, J.S.: ‘Study for optical manipulation of a surfactant-covered droplet using lattice Boltzmann method’, Biomicrofluidics, 2014, 8, (2), pp. 024104–1–15 (doi: 10.1063/1.4868368).
-
8)
-
23. Farhat, H., Celiker, F., Singh, T., Lee, J.S.: ‘A hybrid lattice Boltzmann model for surfactant-covered droplets’, Soft Matter,2011, 7, pp. 1968–1985 (doi: 10.1039/c0sm00569j).
-
9)
-
5. Farhat, H., Lee, J.S.: ‘Suppressing the coalescence of surfactant-covered micro-droplet in the multi-component lattice Boltzmann method’, Microfluid Nanofluid, 2011, 11, pp. 137–143 (doi: 10.1007/s10404-011-0780-y).
-
10)
-
3. Janssen, J.J.M., Boon, A., Agterof, W.G.M.: ‘Influence of dynamic interfacial properties on droplet breakup in simple shear flow’, AIChE J., 1994, 40, (12), pp. 1929–1939 (doi: 10.1002/aic.690401202).
-
11)
-
7. Stone, H.A., Leal, L.G.: ‘The effects of surfactants on drop deformation and breakup’, J. Fluid Mech., 1990, 220, pp. 161–186 (doi: 10.1017/S0022112090003226).
-
12)
-
2. Langevin, D.: ‘Rheology of adsorbed surfactant monolayers at fluid surfaces’, Annu. Rev. Fluid Mech., 2014, 46, pp. 47–65 (doi: 10.1146/annurev-fluid-010313-141403).
-
13)
-
1. Edwards, D.A., Brenner, H., Wasan, D.T.: ‘Interfacial transport processes and rheology’ (Butterworth-Heinemann, Philadelphia, 1991).
-
14)
-
20. He, X., Chen, S., Doolen, G.D.: ‘A Novel Thermal Model for the Lattice Boltzmann Method in Incompressible Limit’, J. Comput. Phys.,1998, 146, pp. 282–300 (doi: 10.1006/jcph.1998.6057).
-
15)
-
8. Eggleton, C.D., Tsai, T., Stebe, K.J.: ‘Tip streaming from a drop in the presence of surfactants’, Phys. Rev. Lett., 2001, 87, pp. 048302–1–4 (doi: 10.1103/PhysRevLett.87.048302).
-
16)
-
17. Gunstensen, A.K., Rothman, D.H.: ‘Lattice Boltzmann model of immiscible fluids’, Phys. Rev. A,1991, 43, pp. 4320–4327 (doi: 10.1103/PhysRevA.43.4320).
-
17)
-
27. Pal, R.: ‘Shear Viscosity Behavior of Emulsions of Two Immiscible Liquids’, J. Colloid Interf. Sci.,2000, 225, pp. 359–366 (doi: 10.1006/jcis.2000.6776).
-
18)
-
18. Lishchuk, S., Care, C., Halliday, I.: ‘Lattice Boltzmann algorithm for surface tension with greatly reduced microcurrents’, Phys. Rev. E,2003, 67, pp. 036701–1–5 (doi: 10.1103/PhysRevE.67.036701).
-
19)
-
24. Farah, M.A., Oliveira, R.C., Caldas, J.N., Rajagopal, K.: ‘Viscosity of water-in-oil emulsions: Variation with temperature and water volume fraction’, J. Petrol. Sci. Eng.,2005, 48, (3–4), pp. 169–184 (doi: 10.1016/j.petrol.2005.06.014).
-
20)
-
4. Bos, M.A., van Vliet, T.: ‘Interfacial rheological properties of adsorbed protein layers and surfactants: a review’, Adv. Colloid Interface Sci., 2001, 91, (3), pp. 437–471 (doi: 10.1016/S0001-8686(00)00077-4).
-
21)
-
12. Li, Z.T., Li, G.J., Huang, H.B., Lu, X.Y.: ‘Lattice Boltzmann study of electrohydrodynamic drop deformation with large density ratio’, Int. J. Modern Phys. C, 2011, 22, (7), pp. 729–744 (doi: 10.1142/S0129183111016580).
-
22)
-
11. Farokhirad, S., Lee, T., Morris, J.F.: ‘Effects of inertia and viscosity on single droplet deformation in confined shear flow’, Commun. Comput. Phys., 2013, 13, (3), pp. 706–724.
-
23)
-
25. Chhabra, R.P., Richardson, J.F.: ‘Non-Newtonian Flow and Applied Rheology: Engineering Applications’ (Butterworth-Heinemann, Burlington2008).
-
24)
-
22. Stone, H.A.: ‘A simple derivation of the time-dependent convective-diffusion equation for surfactant transport along a deforming interface’, Phys. Fluids A,1990, 2, pp. 111–112 (doi: 10.1063/1.857686).
-
25)
-
9. Feigl, K., Megias-Alguacil, D., Fischer, P., Windhab, E.J.: ‘Simulation and experiments of droplet deformation and orientation in simple shear flow with surfactants’, Chem. Eng. Sci., 2007, 62, (12), pp. 3242–3258 (doi: 10.1016/j.ces.2007.02.008).
-
26)
-
14. Kondaraju, S., Farhat, H., Lee, J.S.: ‘Study of aggregational characteristics of emulsions on their rheological properties using the lattice Boltzmann approach’, Soft Matter, 2012, 8, pp. 1374–1384 (doi: 10.1039/c1sm06193c).
-
27)
-
26. Escudier, M.P., Gouldson, I.W., Pereira, A.S., Pinho, F.T., Poole, R.J.: ‘On the reproducibility of the rheology of shear-thinning liquids’, J. Non-Newtonian Fluid Mech.,2001, 97, (2–3), pp. 99–124 (doi: 10.1016/S0377-0257(00)00178-6).
http://iet.metastore.ingenta.com/content/journals/10.1049/mnl.2014.0426
Related content
content/journals/10.1049/mnl.2014.0426
pub_keyword,iet_inspecKeyword,pub_concept
6
6