Simulation of the evolution of disturbances in an evaporating liquid film

L. A. Prokudina

South Ural State University, Chelyabinsk, Russian Federation

Abstract: We present a nonlinear simulation describing the state of a viscous liquid film's free surface during gravitational flow and heat and mass transfer processes. It is a nonlinear fourth-order partial differential equation that contains both spatial and time derivatives. The model coefficients include surface tension, thermocapillary forces, and evaporation. We converted it to a difference equation, an analog of the initial simulation of the liquid film's free surface. We developed computational algorithms to study the instability and free-surface behavior of a liquid film's wave flow at moderate Reynolds numbers. We conducted computational experiments on the nonlinear evolution of disturbances and identified unstable flow regimes in a liquid water film, particularly those with Marangoni instability. We present the results of numerical simulation of the nonlinear evolution of disturbances and the formation of the evaporating liquid film's free surface state, which can be applied to the design and upgrades of manufacturing equipment and processes.

Keywords: liquid film, evaporation, instability, Marangoni number.

DOI: 10.51790/2712-9942-2024-5-4-11