Enhanced evaporative transfer in porous materials with leaf-inspired geometriesWednesday (19.06.2019) 12:00 - 12:15
Tuning material geometry is a passive technique for enhancing heat transfer in thermal exchangers. From a biology perspective, certain morphological aspects of leaves, plants’ multifunctional exchangers, have been associated with increased leaf transpiration and convective cooling, from microscale features of leaf tissues to leaf overall shapes. With this information, previous biomimetic research has hypothesized leaf protrusions, such as marginal teeth or lobes, to provide geometrical insights on enhanced heat transfer of evaporative materials. To test this hypothesis, features of leaf shapes were abstracted and translated into families of two and three-dimensional geometries with protrusions of same surface area but variable elongation. The evaporative performance of such geometries was tested with materials of different porosities in controlled environments, under different airflow regimes. Evaporative models were fabricated by laser-cutting paper, textiles and cellulose sponge. This research investigates the correlation between evaporative heat transfer and increased protrusion aspect-ratio (from tooth to spike and from circular to elliptic), for different environmental conditions. The impact of material, associated porosity, shape and evaporation for the enhancement of heat transfer is discussed. This biomimetic research elucidates on the potential of plant thermodynamics and leaf-inspired geometries to inform design of evaporation-assisted thermal systems.