Two- and three-dimensional numerical simulations of sessile droplet evaporating on heated substrate

Paul G. Chen (1) , Jalil Ouazzani (2) , Qiusheng Liu (3)

1 M2P2 - Laboratoire de Mécanique, Modélisation et Procédés Propres
2 Arcofluid Consulting LLC, 309 N Orange Ave, Orlando, FL 32801, USA
3 Institute of Mechanics, Chinese Academy of Sciences

It cannot be expected that two-dimensional (2D) numerical results give an accurate representation of the three-dimensional (3D) physics of sessile drop evaporation when surface-tension-induced (Marangoni) flow is not symmetric. Also, a 2D model only considers the components of interface curvature lying in the computational plane, whereas the out-of-plane components are neglected. This means that surface-tension-driven hydrodynamic instabilities can usually not be captured in a realistic way. Developing a high resolution numerical method for the simulation of two-phase heat and mass transfer is a viable way of getting deeper insights into such phenomena, and as consequence to better understand them. A reliable and flexible numerical method is developed in the present paper in order to achieve this goal. The method is applied to the simulation of sessile drop evaporation phenomena. Within this framework, a numerical model is developed using the PHOENICS Computational Fluid Dynamics software, which permits a high flexibility and sustainability of the model. The Finite Volume discretization method is used to solve the governing equations of the problem. The method is developed in two- and three-dimension. A mass-conservative Volume-of-Fluid (VOF) interface tracking method is adopted to capture the position of the two-phase interface and its influence on the fluids flow. For the latter two VOF methods have been developed the CICSAM and the THINC-WLIC methods. Marangoni, capillary forces, static contact angles and evaporation are also developed and included in the model. The developed model is applied to the evaporation of well-defined sessile drop where experimental data are available. We investigate the coupled physical mechanism during the evaporation of a pinned drop that partially wets on a heated substrate. The model accounts for mass transport in surrounding air, Marangoni and gravitational convection inside the drop and heat conduction in the substrate as well as moving interface. We show that under some specific circumstances we have transition from 2D axisymmetric to 3D patterns.

Domaines: Mécanique des fluides [physics.class-ph]

Paul G. Chen, Jalil Ouazzani, Qiusheng Liu. Two- and three-dimensional numerical simulations of sessile droplet evaporating on heated substrate. IMA9 – 9th Conference of the International Marangoni Association, Aug 2018, Guilin, China. ⟨hal-01875859⟩