The purpose of this study is to use a weak light source with spatial distribution to realize light-driven fluid by adding high-absorbing nanoparticles to the droplets, thereby replacing a highly focused strong linear light source acting on pure droplets.
First, Fe3O4 nanoparticles with high light response characteristics were added to the droplets to prepare nanofluid droplets, and through the Gaussian light-driven flow experiment, the Marangoni effect inside a nanofluid droplet was studied, which can produce the surface tension gradient on the air/liquid interface and induce the vortex motion inside a droplet. Then, the numerical simulation method of multiphysics field coupling was used to study the effects of droplet height and Gaussian light distribution on the flow characteristics inside a droplet.
Nanoparticles can significantly enhance the light absorption, so that the Gaussian light is enough to drive the flow, and the formation of vortex can be regulated by light distribution. The multiphysics field coupling model can accurately describe this problem.
This study is helpful to understand the flow behavior and heat transfer phenomenon in optical microfluidic systems, and provides a feasible way to construct the rapid flow inside a tiny droplet by light.
Ethics statement: This article does not contain any studies involving human or animal participants.
Funding statement: This work was supported by the Key Research and Development Program of Shaanxi Province (Grant No. 2021ZDLSF05-04) and Xi’an University of Architecture and Technology (Grant No. 002/2040221134).
Liu, Z., Yu, Z., Wang, L., Chen, L., Cui, H. and Sun, B. (2023), "Flow mechanism of Gaussian light-induced vortex motion inside a nanofluid droplet", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 33 No. 2, pp. 712-727. https://doi.org/10.1108/HFF-05-2022-0269
Emerald Publishing Limited
Copyright © 2022, Emerald Publishing Limited