Directional Water Wicking on a Metal Surface Patterned by Microchannels

Area of Science:

• Surface science and microfluidics
• Additive manufacturing and materials science
• Computational fluid dynamics

Background:

• Directional wicking is crucial for applications like fuel cells.
• Microchannel surface structuring enhances fluid transport.
• Stainless steel is a suitable material for microchannel fabrication.

Purpose of the Study:

• To simulate and experimentally study directional water wicking on microchanneled surfaces.
• To investigate the influence of geometry scaling and fluid properties on wicking efficiency.
• To determine the effect of static contact angle on water transport.

Main Methods:

• Additive manufacturing using Selective Laser Melting (SLM) to create fin-type microchannel structures.
• Experimental analysis of water transport on fabricated surfaces.
• 3D numerical simulations using Volume of Fluid (VOF) and Lattice-Boltzmann (LBM) methods.

Main Results:

• Wicking efficiency is dependent on dimensionless numbers like Reynolds and Capillary numbers.
• Simulations qualitatively reproduced experimental results, offering insights into microscale dynamics.
• The static contact angle significantly influences wicking, with identified thresholds for transport vanishing and optimal transport.

Conclusions:

• SLM is effective for fabricating microchannel structures for directional wicking.
• Fluid dynamics and surface properties are key parameters for optimizing water transport.
• Contact angle engineering is vital for controlling and enhancing wicking phenomena in microfluidic devices.