Empirical Verification of Theoretical Models on Performance Characteristics of Micro-Pillar Wick Structures

Two-phase passive heat carriers/spreaders are effective thermal management tools. However, their thermal performance is limited due to the transport characteristics of their wick structure. To enhance the performance of passive heat spreaders and expand their use to applications with high heat loads and severe operating environments, better wick structures are being developed. Advancements in the design of these structures have been hampered by a lack of models that can predict fluid flow rate in wicks over a wide range of geometrical parameters. The focus of this study is to find such a model for micro-pillar arrays. The model is intended for use in optimizing an array to achieve maximum liquid permeability at a given hydrostatic pressure. Two wicking devices with different pillar spacings were fabricated. The maximum heat transfer capacities of the devices at various wicking lengths were compared with predictions of selected correlations. A model by Byon et al. [1] predicted the experimental results with reasonable accuracy.