Nonlinear dynamics of confined thin liquid-vapor bilayer systems with phase change

Abstract

We numerically investigate the nonlinear evolution of the interface of a thin liquid-vapor bilayer system confined by rigid horizontal walls from both below and above. The lateral variation of the vapor pressure arising from phase change is taken into account in the present analysis. When the liquid ͑vapor͒ is heated ͑cooled͒ and gravity acts toward the liquid, the deflection of the interface monotonically grows, leading to a rupture of the vapor layer, whereas nonruptured stationary states are found when the liquid ͑vapor͒ is cooled ͑heated͒ and gravity acts toward the vapor. In the latter case, vapor-flow-driven convective cells are found in the liquid phase in the stationary state. The average vapor pressure and interface temperature deviate from their equilibrium values once the interface departs from the flat equilibrium state. Thermocapillarity does not have a significant effect near the thermodynamic equilibrium, but becomes important if the system significantly deviates from it.

Effects of convection and diffusion of the vapour in evaporating liquid films

“…However, for thin films the effects of the vapour stress and viscous dissipation are neglected under the long-wave approximation (see Burelbach et al 1988), unless there is an internal or external flow of the gas in the lateral direction, which causes a shear stress on the interface. The former case was considered by Kanatani (2010) and Kanatani & Oron (2011), where the lateral vapour flow arises from the confined geometry of the gas phase. The latter case has been recently addressed in several works (e.g.…”

Rayleigh–Taylor unstable condensing liquid layers with nonlinear effects of interfacial convection and diffusion of vapour

“…Later, some numerical investigations have considered ambient gas as a mixture of the vapour and an inert (non-condensable) gas in the presence of vapour diffusion by linear or weakly nonlinear analysis (Haut & Colinet 2005;Margerit, Dondlinger & Dauby 2005;Sultan, Boudaoud & Amar 2005). However, vapour convection has usually been either neglected or ignored, except for the LSA by Kanatani (2010Kanatani ( , 2013, the simulations by Kanatani & Oron (2011) and Pillai & Narayanan (2018) and the experimental and numerical studies in Savino et al (2002) and Dehaeck, Rednikov & Colinet (2014). As suggested by Kanatani (2013) and Pillai & Narayanan (2018), to predict what actual patterns emerge from an evaporating film or whether instabilities lead to its rupture, a nonlinear computation is required, because of the time and thickness dependence of the maximum growth mode in the LSA.…”

Instabilities in a horizontal liquid layer in cocurrent gas flow with an evaporating interface

“…Kanatoni [10] has studied the interfacial instability induced by lateral vapor pressure fluctuation in a vapor-liquid system with an evaporating interface. More recently, Kanatani and Oron [11] have studied the nonlinear dynamics of the same system as that in Ref. [10].…”