Dynamics of thin film flows on a vertical fibre with vapor absorption

Fuente: arXiv
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Main Authors: Chattopadhyay, Souradip, Yu, Zihao, Ju, Y. Sungtaek, Ji, Hangjie
Format: Preprint
Published: 2025
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author Chattopadhyay, Souradip
Yu, Zihao
Ju, Y. Sungtaek
Ji, Hangjie
author_facet Chattopadhyay, Souradip
Yu, Zihao
Ju, Y. Sungtaek
Ji, Hangjie
contents Water vapor capture through free surface flows plays a crucial role in various industrial applications, such as liquid desiccant air conditioning systems, water harvesting, and dewatering. This paper studies the dynamics of a silicone liquid sorbent (also known as water-absorbing silicone oil) flowing down a vertical cylindrical fibre while absorbing water vapor. We propose a one-sided thin-film-type model for these dynamics, where the governing equations form a coupled system of nonlinear fourth-order partial differential equations for the liquid film thickness and oil concentration. The model incorporates gravity, surface tension, Marangoni effects induced by concentration gradients, and non-mass-conserving effects due to absorption flux. Interfacial instabilities, driven by the competition between mass-conserving and non-mass-conserving effects, are investigated via stability analysis. We numerically show that water absorption can lead to the formation of irregular wavy patterns and trigger droplet coalescence downstream. Systematic simulations further identify parameter ranges for the Marangoni number and absorption parameter that lead to the onset of droplet coalescence dynamics and regime transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2505_22379
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamics of thin film flows on a vertical fibre with vapor absorption
Chattopadhyay, Souradip
Yu, Zihao
Ju, Y. Sungtaek
Ji, Hangjie
Fluid Dynamics
Water vapor capture through free surface flows plays a crucial role in various industrial applications, such as liquid desiccant air conditioning systems, water harvesting, and dewatering. This paper studies the dynamics of a silicone liquid sorbent (also known as water-absorbing silicone oil) flowing down a vertical cylindrical fibre while absorbing water vapor. We propose a one-sided thin-film-type model for these dynamics, where the governing equations form a coupled system of nonlinear fourth-order partial differential equations for the liquid film thickness and oil concentration. The model incorporates gravity, surface tension, Marangoni effects induced by concentration gradients, and non-mass-conserving effects due to absorption flux. Interfacial instabilities, driven by the competition between mass-conserving and non-mass-conserving effects, are investigated via stability analysis. We numerically show that water absorption can lead to the formation of irregular wavy patterns and trigger droplet coalescence downstream. Systematic simulations further identify parameter ranges for the Marangoni number and absorption parameter that lead to the onset of droplet coalescence dynamics and regime transitions.
title Dynamics of thin film flows on a vertical fibre with vapor absorption
topic Fluid Dynamics
url https://arxiv.org/abs/2505.22379