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Heat Transfer at the Contact Line• Heat transfer at the contact line was modeled using a Kelvin-Clapeyron approach.dΓdy = − &m evp = C⎛⎝⎜M2π RT1 2⎞⎠⎟⎧⎪P vMh fg⎨⎩⎪ RT vT i( T i− T v )+ V P l vRT i( )P l− P v⎫⎪⎬⎭⎪13ν 1ddy⎡⎢⎣( σ o− γ ( T lv− T v ))δ 3 δ '''− γδ 3 δ " dT lvdy + 3A23γδδ '+δ 2dT lvdy⎤⎥⎦⎡⎛+ a( T lv− T v )− b σδ "− γ ( T lv− T v )δ "− A ⎞ ⎤⎢⎝⎜δ 3 ⎠⎟ ⎥ = 0⎣⎦• Since the pressure and difference can be written in terms <strong>of</strong> the film thickness, andthe temperature difference is measured or set, the final equation can be written as a4th order differential equation for the film thickness, δ.• Boundary conditions set the film thickness and curvature at both ends <strong>of</strong> the domain.– These conditions are established from experimental observations.COMSOL User's Conference, Boston 8
Simulation Results• COMSOL simulations were performedby splitting the 4 th order equation intotwo 2 nd order equations.– Splitting allowed for more controlover boundary conditions.– Limited us to steady-statesimulation.1.00.80.60.40.2Adsorbed Film Thickness (nm)41040• We were primarily interested in whetherthe model could simulate the curvaturepr<strong>of</strong>iles we observe experimentally.70.00.20.40.6Dimensionless Position0.81.0• Peak in curvature only occurs for smallvalues <strong>of</strong> the adsorbed film thicknesscorresponding to high values <strong>of</strong> thedisjoining pressure.6543Adsorbed Film Thickness (nm)410402• Steep curvature gradient required topump liquid into the transition region forevaporation.100.00.20.40.6Dimensionless Position0.81.0COMSOL User's Conference, Boston 9
Page 1 and 2: Presented at the COMSOL Conference
Page 3 and 4: Evaporation from Transition RegionE
Page 5 and 6: Reflectivity/Interferometry Techniq
Page 7: Fluid Flow Model• Lubrication app
Page 11 and 12: Simulation Results - Octane & Penta
Page 13 and 14: AcknowledgementsLiftof</str
Page 15: COMSOL User's Conference, Boston 15

Effect of Surface Structure on Liquid Wettability at ... - COMSOL.com

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