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Surface Adhesion (Adsorption) in LBM
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Key Papers Martys, N. and H. Chen, 1996, PRE 53, 743- 750 Raiskinmäki, P., A. Koponen, J. Merikoski, and J. Timonen, 2000, Comp. Materials Sci. 18, 7 – 12
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Key Books Adamson, A. W., and A.P. Gast, Physical Chemistry of Surfaces, New York, John Wiley & Sons, Inc., 1997. Israelachvili, J. N., Intermolecular and Surface Forces, 2nd ed. Academic Press, London, 1992.
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Wetting http://www.hdm-stuttgart.de/projekte/printing-inks/b_sel42.jpg
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Wetting http://psii.kist.re.kr/Teams/psii/research/Con_4.jpg
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Geometrically-controlled Superhydrophobic surfaces http://www.nature.com/nmat/journal/v1/n1/images/nmat715-f1.jpg
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LBM Adhesive Force Formula s is a ‘switch’ that takes on value 1 if the site at x + e a t is a solid and is 0 otherwise We seem to have flexibility in the choice of the pre-sum factor; the papers cited use or
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Computation of // Compute psi, Eq. (61). for( j=0; j<LY; j++) for( i=0; i<LX; i++) if( !is_solid_node[j][i]) { psi[j][i] = 4.*exp( -200. / ( rho[j][i])); }
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Sforce // Compute interaction force, Eq. (66). for( j=0; j<LY; j++) { jp = ( j<LY-1)?( j+1):( 0 ); jn = ( j>0 )?( j-1):( LY-1); for( i=0; i<LX; i++) { ip = ( i<LX-1)?( i+1):( 0 ); in = ( i>0 )?( i-1):( LX-1); if( !is_solid_node[j][i]) { sum_x=0.; sum_y=0.; if( is_solid_node[j ][ip]) // neighbor 1 { sum_x = sum_x + WM*ex[1]; sum_y = sum_y + WM*ey[1]; } if( is_solid_node[jp][i ]) // neighbor 2 { sum_x = sum_x + WM*ex[2]; sum_y = sum_y + WM*ey[2]; } if( is_solid_node[j ][in]) // neighbor 3 { sum_x = sum_x + WM*ex[3]; sum_y = sum_y + WM*ey[3]; }
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Sforce if( is_solid_node[jn][i ]) // neighbor 4 { sum_x = sum_x + WM*ex[4]; sum_y = sum_y + WM*ey[4]; } if( is_solid_node[jp][ip]) // neighbor 5 { sum_x = sum_x + WD*ex[5]; sum_y = sum_y + WD*ey[5]; } if( is_solid_node[jp][in]) // neighbor 6 { sum_x = sum_x + WD*ex[6]; sum_y = sum_y + WD*ey[6]; } if( is_solid_node[jn][in]) // neighbor 7 { sum_x = sum_x + WD*ex[7]; sum_y = sum_y + WD*ey[7]; } if( is_solid_node[jn][ip]) // neighbor 8 { sum_x = sum_x + WD*ex[8]; sum_y = sum_y + WD*ey[8]; } sforce_x[j][i] = -Gads * psi[j][i] * sum_x; sforce_y[j][i] = -Gads * psi[j][i] * sum_y; }
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Contact Angles in SCMP LBM Interplay between these forces will determine wetting Cohesive force: Adhesive force:
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Young’s Equation?
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Contact Angles in SCMP LBM Assume uniform liquid or vapor surroundings:
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Contact Angles in LBM Assume uniform surroundings: LiquidVapor
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Contact Angles in LBM Assume uniform surroundings: Liquid surrounded by solidVapor surrounded by solid
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Contact Angles in LBM Zero degree contact angle: –Adhesive force equal to cohesive force for liquid Liquid surrounded by solidLiquid
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Contact Angles in LBM 180 degree contact angle: –Adhesive force on vapor equal to cohesive force for vapor Vapor surrounded by solidVapor
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Contact Angles in LBM 90 degree contact angle: –Adhesive force on vapor equal to cohesive force for ‘interface’ (= [ l + v ) Interface surrounded by solidInterface
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Adsorption A svl : Hamaker constant for interaction of solid with vapor through liquid : Disjoining pressure (P relative to flat, free interface)
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Adsorption vap =85.7 vap =85.7857 vap =86.1285
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Capillary Condensation A vll : Hamaker constant for interaction of liquid with liquid through vapor : Disjoining pressure (P relative to flat, free interface)
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Capillary Condensation vap =86.557
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Adsorption/Capillary Condensation
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Hysteretic Wetting/Drying of Angular Pores (Tuller, Or, and Dudley,1999 WRR) Saturation as a function of p at high tension Drainage radius Imbibition radius Shape factor Young-Laplace (zero contact angle) Filled cross-sectional area p as a function of saturation at high tension
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Hysteretic Wetting and Drying
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Hysteritic Wetting and Drying
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Invasion Percolation
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Capillary Number v inlet/outlet velocity viscosity of injected fluid n porosity interfacial tension between fluids contact angle Friedman, 1999. J. Adhesion Sci Technol. 13(12), 1495-1518.
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Pore Selection and Impact of Ca on Pore Penetration 2,500 ts/movie step r = 7.5 r = 6.5 r = 5 v 10 -3 Ca 2 x 10 -4 v 10 -4 Ca 2 x 10 -5
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Viscosity Ratio For D2Q9 LBM:
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Phase Diagram Lenormand et al. 1988. J. Fluid Mech. 189, 165-187. Air/Viscous OilGlucose Soln./ Oil Air/Viscous Oil
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Frette et al., 1997. PRE 55(3) 2969-2975. Viscosity-Matched Fluids Monolayer of 0.7 mm beads
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No Gravity Gravity Drainage and gravity stabilization
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