Characterization of Hemi-Wicking in Micro-Engineered Surfaces Using Micro-PTV and Phase-Field Lattice Boltzmann Method

Micro-engineered surfaces have seen extensive applications in a broad range of natural and engineering processes such as thermal management, bioengineering, and petrochemical industries. These porous surfaces offer a major advantage of enhanced flow through narrow conduits via capillary wicking and provide a large surface-area-to-volume ratio. The wicking performance in these systems could be further improved by understanding the microscale flow dynamics and their variation with the micro-engineered surfaces. This study investigates the effect of different structures on wicking enhancement via a combination of numerical, experimental, and analytical studies. The numerical approach is based on the three-dimensional phase-field Lattice Boltzmann method, whereas the experimental validation takes advantage of the microfabrication techniques and 3D micro-PTV to track the wicking flow. The results explore the advancing liquid front in different geometries to model wicking in micro-structured surfaces. Further it analyzes the effects of pitch-to-diameter and height-to-pitch ratios on wicking enhancement. The results are corroborated with analytical correlation developed based on thermodynamic energy balance, showing good agreement with the numerical and experimental data.