액적 증발의 계산시간 단축에 관한 수치적 연구

초록

Numerical study on reducing computation time is performed for sessile droplet evaporation. The conservation equations of mass, momentum and vapor concentration are solved by employing the level-set method which is modified to include the effect of phase change. One of the major difficulties in computing the whole period of droplet evaporation arises from the fact that the surface tension term in the momentum equation causes a serious time step restriction for stable computation. In this work, the time step constraint is avoided by simplifying the droplet shape as a spherical cap whose curvature is spatially uniform so that the surface tension term is treated as a part of the pressure term. The droplet surface is calculated geometrically and then the level-set function is reconstructed from the droplet surface. The numerical result for sessile droplet evaporation in stationary air shows good agreement with the experimental data reported in the literature. The effects of external flow velocity, temperature and contact angle on the droplet evaporation rate are quantified.

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