Study on the Flow Characteristics of Microscale Copper Inverse Opal Wick Structures

Ultra-thin heat pipes are extensively used to address heat dissipation challenges in compact electronic devices with limited space. Research on new types of micro-porous wick is crucial for enhancing the heat transfer of ultra-thin heat pipes. The hydraulic transport properties of micro-porous wick structures are crucial factors for the applications. The inverse opal (IO) micro-porous metal structure has gained extensive attention for its ordered periodic arrangement and high porosity characteristics. In the paper, the copper inverse opal (CIO) and gradient CIO are fabricated by a template-assisted deposition method. Experimental measurements are conducted to study the fluid ascent process within the CIO structure. In addition, a face-centered cubic geometric model is established based on the structure information obtained by a scanning electron microscope (SEM). The calculation employs a porous media model and takes into account the resistance characteristics in the initial phase. The relative error between the simulation and experimental results is less than 7.7%. Furthermore, the fabricated gradient CIO structure is uniform and exhibits a higher permeability than single-pore CIO. The permeability of this gradient CIO is about 1.9-3.2 x 10-14 m2. Understanding the microscopic liquid transport process within CIO structures is of great importance in the selection and optimization of capillary wick structures.