Main Article Content

Ndivhuwo Musehane Rhameez Herbst

Abstract

Computational Fluid Dynamics (CFD) is used to study the spreading process of a water droplet with a radius of 0.00275mm impacting a wax surface at a velocity of 1.18ms−1 . This type of flow is considered to be Multiphase, incompressible, laminar, surface tension dominated and is governed by the Navier stokes and continuity equations. To accurately model the spreading process 3 different contact angle models are investigated, two of which take into account the moving contact line. The governing equations are solved using the open source C++ library OpenFOAM, which uses a Finite Volume Method (FVM) of discretization and a Volume Of Fluid (VOF) interface capturing method. The VOF method is known to produce unphysical velocities when high pressure gradients exist between the two phases, thus a numerical improvement is implemented to reduce the magnitudes of the unphysical velocities. The improvement reduces the magnitudes of the unphysical velocities and as shown in literature their magnitudes increase with an increase in surface tension dominance. The improvement is implemented together with different contact angle models and results obtained show that contact angle models that take into account the moving contact line gives a good correlation of the spreading diameter obtained numerically with the one obtained experimentally.

Article Details

Keywords

VOF, Dynamic contact angle, Droplet, Surface tension, OpenFOAM

Refrences
[1] J. Fukai, Z. Zhao, D. Poulikakos, C.M. Megaridis, O. Miyatake. Modeling of the deformation of a liquid droplet impinging upon a flat surface. Physics of Fluids A: Fluid Dynamics. 5 (1993) 2588-99.
[2] Š. Šikalo, H.-D. Wilhelm, I. Roisman, S. Jakirlić, C. Tropea. Dynamic contact angle of spreading droplets: Experiments and simulations. Physics of Fluids. 17 (2005) 062103.
[3] C.W. Hirt, B.D. Nichols. Volume of fluid (VOF) method for the dynamics of free boundaries. Journal of computational physics. 39 (1981) 201-25.
[4] S. Osher, J.A. Sethian. Fronts propagating with curvature-dependent speed: algorithms based on Hamilton-Jacobi formulations. Journal of computational physics. 79 (1988) 12-49.
[5] F.H. Harlow, J.E. Welch. Numerical calculation of time‐dependent viscous incompressible flow of fluid with free surface. The physics of fluids. 8 (1965) 2182-9.
[6] M. Sussman, E.G. Puckett. A coupled level set and volume-of-fluid method for computing 3D and axisymmetric incompressible two-phase flows. Journal of computational physics. 162 (2000) 301-37.
[7] F.H. Harlow, J.P. Shannon. The splash of a liquid drop. Journal of Applied Physics. 38 (1967) 3855-66.
[8] A.M. Worthington. XXVIII. On the forms assumed by drops of liquids falling vertically on a horizontal plate. Proceedings of the royal society of London. 25 (1877) 261-72.
[9] R. Rioboo, M. Marengo, C. Tropea. Time evolution of liquid drop impact onto solid, dry surfaces. Experiments in fluids. 33 (2002) 112-24.
[10] J.U. Brackbill, D.B. Kothe, C. Zemach. A continuum method for modeling surface tension. Journal of computational physics. 100 (1992) 335-54.
[11] D.J. Harvie, M. Davidson, M. Rudman. An analysis of parasitic current generation in volume of fluid simulations. Applied mathematical modelling. 30 (2006) 1056-66.
[12] R.I. Issa, A. Gosman, A. Watkins. The computation of compressible and incompressible recirculating flows by a non-iterative implicit scheme. Journal of Computational Physics. 62 (1986) 66-82.
[13] S. Esmaeili, M. Nasiri, N. Dadashi, H. Safari. Wave function properties of a single and a system of magnetic flux tube (s) oscillations. Journal of Geophysical Research: Space Physics. 121 (2016) 9340-55.
[14] Y.A. Cengel. Fluid mechanics. Tata McGraw-Hill Education2010.
[15] R.E. Johnson Jr, R.H. Dettre, D.A. Brandreth. Dynamic contact angles and contact angle hysteresis. Journal of Colloid and Interface science. 62 (1977) 205-12.
[16] S. Ganesan. On the dynamic contact angle in simulation of impinging droplets with sharp interface methods. Microfluidics and nanofluidics. 14 (2013) 615-25.
[17] R. Cox. The dynamics of the spreading of liquids on a solid surface. Part 1. Viscous flow. Journal of Fluid Mechanics. 168 (1986) 169-94.
[18] A.C.D.-o. Soil, Rock. Standard test methods for one-dimensional consolidation properties of soils using incremental loading. ASTM International2004.
Section
Mechanical Engineering

How to Cite

Musehane, N., & Herbst, R. (2019). Numerical Investigation of Different Dynamic Contact Angle Models for a Droplet Impacting a Surface in OpenFOAM. Mapta Journal of Mechanical and Industrial Engineering (MJMIE), 3(1), 9-17. https://doi.org/10.33544/mjmie.v3i1.96