Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

Wenkai, Ge; Lu, Gui; Xu, Xianfan; Wang, Xiao‐Dong

doi:10.1515/phys-2016-0055

Cited by 11 publications

(14 citation statements)

References 34 publications

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“…In contrast with our results, simulations by Reis et al [43] found that a lower contact angle reduced the spreading ratio. Nevertheless, other Lattice-Boltzmann studies done by [41,44], and [42] performed on simplified porous media (regular grid of cylindrical or square pores) have also shown that a lower contact angle increases the spreading rate. The disagreement between the former numerical model [43] and the Lattice-Boltzmann studies can be explained by a different model used for describing the contact angle dynamics and the surface wettability.…”

Section: Resultsmentioning

confidence: 94%

Water transport and absorption in pharmaceutical tablets – a numerical study

et al. 2019

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The quality of a coated pharmaceutical tablet can be strongly affected by the interactions of water droplets with the porous substrate during processes such as coating process. Three different mechanisms co-exist in the coating process: water spreading, absorption and evaporation. Disentangling the fundamental understanding of these phenomena can therefore be crucial for achieving a higher quality of the products (e.g. a longer shelf-life of the tablets) and for controlling the efficiency of the process. This paper aims to investigate the spreading and absorption mechanisms after droplet impingement on a tablet using a Lattice-Boltzmann methodology. Our numerical results (droplet height and spreading, penetration depth and absorbed volume) are in a good agreement with experimental data and numerical simulations available in the literature. In particular, the spreading phase is characterised by the capillary spreading time scale, as confirmed by previous studies. In contrast to previous studies, we find that the absorption process begins at times shorter than the capillary spreading time but with a different power-law in the absorbed volume. We explain this behaviour through a modified Washburn law that takes into account three-dimensional effects. Our data can be used as a benchmark to test novel mathematical models.

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Section: Resultsmentioning

confidence: 94%

Water transport and absorption in pharmaceutical tablets – a numerical study

et al. 2019

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“…Ambient conditions greatly influence the absorption process and can modify the mass transfer by orders of magnitude. Furthermore, interaction with the wall has a major impact on droplet properties and the gas-fluid interaction [18]. A significant amount of research has been done on the topic of interface mass transfer during the better part of the last century [19], but a simple and comprehensive unified model is still not available.…”

Section: Mass Transfer Dynamicsmentioning

confidence: 99%

Numerical analysis of sulfur dioxide absorption in water droplets

et al. 2020

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AbstractMass transfer between the phases is a cornerstone of many technological processes and presents a topic whose understanding and modelling is of high importance. For instance, absorption of gases in liquid droplets is an underlying phenomenon for the desulfurization of flue gases in wet scrubbers. Wet scrubbing is an efficient cleaning method where the liquid is sprayed in a stream of rising gases, removing pollutants due to the concentration difference between the gas phase and droplets. A model for absorption in water droplets has been developed to describe the complex physical and chemical interactions during the exposure to flue gases. The main factors affecting the absorption are the mass transfer of pollutants through the gas–droplet interface and the aqueous phase chemistry in a droplet. The mass transfer coefficient, which has been modeled with several approaches, is the most significant parameter regulating the absorption dynamic into the droplet, while the in-droplet chemistry controls the maximum quantity of dissolved pollutants. Dissociation of sulfur dioxide and the chemical reactions in seawater have been described by the equilibrium reactions. Afterward, the influence of the mass transfer coefficient has been investigated, and the model has been validated against the literature data on a single droplet scale. Obtained results are comparable with the experimental measurements and indicate the applicability of the model for the design and development of industrial scrubbers.

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“…These models provide the design framework for paper-like materials and paper-based devices. Liquid flow in paper-like materials can be modelled by different approaches: Lucas-Washburn models [15,[17][18][19][20], Darcy's model [21][22][23][24][25] and computational fluid dynamics (CFD) [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Wicking in Paper Strips under Consideration of Liquid Absorption Capacity

2020

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Paper-based microfluidic devices have the potential of being a low-cost platform for diagnostic devices. Electrical circuit analogy (ECA) model has been used to model the wicking process in paper-based microfluidic devices. However, material characteristics such as absorption capacity cannot be included in the previous ECA models. This paper proposes a new model to describe the wicking process with liquid absorption in a paper strip. We observed that the fluid continues to flow in a paper strip, even after the fluid reservoir has been removed. This phenomenon is caused by the ability of the paper to store liquid in its matrix. The model presented in this paper is derived from the analogy to the current response of an electric circuit with a capacitance. All coefficients in the model are fitted with data of capillary rise experiments and compared with direct measurement of the absorption capacity. The theoretical data of the model agrees well with experimental data and the conventional Washburn model. Considering liquid absorption capacity as a capacitance helps to explain the relationship between material characteristics and the wicking mechanism.

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Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

Cited by 11 publications

References 34 publications

Water transport and absorption in pharmaceutical tablets – a numerical study

Water transport and absorption in pharmaceutical tablets – a numerical study

Numerical analysis of sulfur dioxide absorption in water droplets

Wicking in Paper Strips under Consideration of Liquid Absorption Capacity

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