2019_PhysRevFluids_Indigo.pdf (6.93 MB)
Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates
journal contributionposted on 2019-04-18, 00:00 authored by Uddalok Sen, Souvick Chatterjee, Julie Crockett, Ranjan Ganguly, Lisha Yu, Constantine M. Megaridis
Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed.
The authors acknowledge the financial support from Kimberly-Clark Corporation during the course of the present study. The laser marking system, scanning electron microscope, and optical profilometer of the Nanotechnology Core Facility at UIC were used for sample fabrication and characterization, with the valuable assistance of Jared M. Morrissette and Theodore P. Koukoravas of the UIC Micro/Nanoscale Fluid Transport Laboratory. The authors would also like to thank David Mecha of the Engineering Machine Shop at UIC for assistance with sample fabrication. Some experiments were performed with assistance from Dr. Tamal Roy of the UIC Micro/Nanoscale Fluid Transport Laboratory.
Publisher StatementCopyright @ American Physical Society
CitationSen, U., Chatterjee, S., Crockett, J., Ganguly, R., Yu, L. S., & Megaridis, C. M. (2019). Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates. Physical Review Fluids, 4(1). doi:10.1103/PhysRevFluids.4.014002
PublisherAmerican Physical Society