Mechanism of Liquid Dispersion Enhancement by the Hydrophobic Wire Mesh at Macro- and Micro-Scale

Abstract

The hydrophobic surface-modified stainless steel wire mesh (SSM) has been proven to enhance the liquid dispersion effectively, which has a significant impact on the mass transfer and micromixing performance. Therefore, the mechanism of liquid dispersion enhancement by SSM is significantly valuable. However, the mechanism of liquid dispersion enhancement by SSM has not been revealed up to now. In this work, hydrodynamics of the liquid flow pattern and liquid velocity field of liquid jet impacting on SSM were observed and analyzed, aiming to elucidate the intensification mechanism at macro-and micro-scale. The cone angle of SSM could be reached ∼80°with a daughter droplet diameter of ∼1.7 mm. The cone angle was enlarged by 60%, and the daughter droplet diameter was 20% smaller from SSM with smaller fiber and opening. Results of liquid velocity field showed that the better liquid dispersion by SSM mainly resulted from the larger horizontal velocity, which was up to −0.5 to 0.7 m/s by SSM compared with −0.1 to 0.1 m/s by NSM. A mechanism of liquid dispersion enhancement by SSM was suggested and validated as follows: the wettability of wire mesh affected the flow pattern by various velocity fields to form different cone angles at macro-scale; the micro− nano structure on SSM retained the liquid with the Cassie model, which led to smaller dissipation energy. More energy was transformed to the surface and kinetic energy of daughter droplets with a smaller diameter. This work provided an insight into liquid dispersion enhancement by surface modification, which can guide the rational liquid dispersion design.