Effectiveness of the heat sink based on PCM filled aluminum matrix as afunction of its geometry

Abstract

Effective thermal management is essential for electronic equipment cooling systems, particularly in applications involving heat dissipation. Phase change materials (PCM) offer a promising solution by utilizing latent heat to manage temperature fluctuations.
Our study is dedicated to development of a cooling system that integrates phase change materials (PCM) with an aluminum matrix/cell. Understanding the influence of matrix geometry on heat removal efficiency and identifying critical geometric parameters ensures the optimization of designs for reproducible and scalable manufacturing.
The study employs both experimental and numerical methods to assess the thermal performance of PCM-based systems by evaluating individual cells that represent the overall aluminum matrix geometries. We use 3D printing technologies for matrix production, and computer assisted data acquisition for temperature tracking. In addition to the experimental work, numerical simulations were conducted and a convection-incorporating model was developed to predict the effects of specific matrix geometries, namely basic hexagonal shapes, tree pattern hexagonal shapes, and snowflake pattern hexagonal shapes, on thermal performance. The experimental measurements were verified by comparing them with the results of computer simulation of the developed system.
Key findings reveal that bio-inspired aluminum matrix geometries, particularly the Tree and Snowflake patterns, demonstrated superior thermal performance compared to the standard hexagonal configuration across all heat flux conditions. The Tree Pattern achieved a thermal response nearly identical to the Snowflake design while offering approximately 8% lower aluminum mass and 4 % greater PCM volume, making it more favorable for lightweight and scalable applications. Among the paraffin-based PCMs tested, the thermal response varied significantly with target temperature. At 323 K (50 °C), the commercial Therabath mixture (melting point: 322 K) (49 °C), reached the target temperature more rapidly than Eicosane (308 K) (35 °C), and Octadecane (301 K) (28 °C), indicating efficient performance during the initial melting phase. However, at 343 K (70 °C), this trend reversed: Eicosane consistently reached the target temperature in the shortest time across all heat flux levels, while the Therabath mixture and Octadecane exhibited slower responses. These results emphasize the combined influence of matrix geometry and PCM selection on the overall efficiency of passive thermal management systems.