Numerical simulation of the hydrodynamics of yield stress fluids during dip coating

Autor: Shichang Chen, Heng-Kuan Zhang, Ya-Ran Yin, Guo-Hua Hu, Wenxing Chen, Xianming Zhang
Přispěvatelé: Université de Lorraine (UL), Université de Lorraine
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Non-Newtonian Fluid Mechanics
Journal of Non-Newtonian Fluid Mechanics, Elsevier, 2021, 298, pp.104675. ⟨10.1016/j.jnnfm.2021.104675⟩
ISSN: 0377-0257
DOI: 10.1016/j.jnnfm.2021.104675⟩
Popis: The literature has treated the dip coating of yield stress fluids with the Bingham number ( B i = τ c / K γ ˙ n , where τc, K, γ ˙ and n are the yield stress, consistency factor, shear rate and power-law exponent, respectively.) being larger than 1, and has ignored the influence of shear-dependent component ( K γ ˙ n ). This work simulated the dip-coating process for various simple yield stress fluids with Bi numbers below 1, and showed the importance of yield stress and shear-dependent component for the hydrodynamics inside the bath as well as the film thickness. The yielded-unyielded boundaries as well as the profiles of flow velocity and shear stress profiles were theoretically determined under final steady state. The main flow characteristics of drainage in the meniscus were captured. Under the negligible effect of surface tension on the film coating, a semi-empirical model of film thickness considering drainage effect is proposed with good prediction performance.
Databáze: OpenAIRE
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