Dynamical behaviour of drops deposited on non-wetted vibrating surfaces

Fecha: 26 de octubre de 2023.
Hora: 12:30 a 13:30.
Lugar: Aula A22.

Ponente: Amirhossein Khazayialiabad (Technical University of Darmstadt, Germany).

Organiza el Grupo de Física de Fluidos y Biocoloides de la UGR.

One of the well-established engineering challenges is dynamical behaviour of drops deposited on non-wetted vibrating surfaces. Despite previous extensive investigations, the internal flow of the nanoparticle-laden sessile drop still poses challenges and lacks a comprehensive understanding [1, 2]. With this in mind, the utilization of simulation tools can provide a comprehensive understanding of the internal dynamics of the droplet, enabling the quantification of velocity and concentration gradients, which are challenging to assess experimentally. Also, controlling the deposition patterns left behind the nanofluid evaporation is essential for various applications especially when it comes to material science and biotechnology [3]. During the upcoming secondment, we strive to shed light on the flow within the drop resting on parahydrophobic substrates, both in the presence and absence of nanoparticles. In addition, the deposition of nanoparticles with different surface properties–that is–hydrophobic, hydrophilic, or neutral, will be extensively studied to gain deeper insights into the impact of such a factor. The proposed study helps advancement of our knowledge of drop systems on vibrating surfaces, particularly in the presence of nanoparticles. Furthermore, it seeks to provide insights into controlling the deposition patterns during nanofluid evaporation, with potential applications in inkjet printing and electronic devices.

The implementation of the first part of the afore-mentioned process involves modelling the drop on a parahydrophobic substrate and incorporating the vibration effect. To this end, under the finite element context, COMSOL Multiphysics software will be used. There are multiple influential parameters among which are drop volume, substrate characteristics, vibration frequency, and amplitude. To capture the water-air interface, the Arbitrary Lagrangian Eulerian (ALE) method has been taken into consideration. By solving time-dependent equations, simulations offer insights into fluid flow patterns, deformation, and transport phenomena, and sensitivity to vibration. When it comes to the deposition, a suitable deposition model in the form of a boundary condition at the substrate will be applied to approximate the deposition front. The operating condition and effective properties of the applied nanofluid will be based on the experimental set up and already existing model in the literature, respectively.

Bibliography
[1] Apratim Sanyal et al. — Precision control of drying using rhythmic dancing of sessile nanoparticle laden droplets. Applied Physics Letters, 2014.
[2] Laxmidhar Nayak et al. — A review on inkjet printing of nanoparticle inks for flexible electronics. Journal of Materials Chemistry C, 2019.
[3] Xin Zhong et al. — Sessile nanofluid droplet drying. Advances in Colloid and Interface Science, 2015.