par Khan, Asif ;Glushchuk, Andrey ;Balapanov, Daniyar ;Iorio, Carlo Saverio
Référence Graphene Week 2023 (PC252-5963892: 4-8 September 2023: Gothenburg, Sweden)
Publication Publié, 2023-09-08
Poster de conférence
Résumé : The enhancement of the evaporation from porous media (PM) remains a significant challenge due to complexity of liquid flow and internal morphology[1]. Nowadays, graphene coating attracts attention for improving surface performance in thermal management applications due to its anisotropic properties. This study is focused on the influence of the graphene on the PM evaporation capability using an innovative experimental technique developed at CREST. The technique utilizes a pressure decrease as a promoting force for the evaporation. In the setup Fig :1 two volumes are separated by a vacuum valve (V1) to keep them at different pressures. A porous sample is placed in one of the volumes (Vol_1). The PM is saturated with degassed pure ethanol using a precise syringe till the vapor saturation. Upon opening of the valve (V1), the vapour expands into the vacuumized second volume (Vol_2) to provide the rapid pressure decrease. The evaporation rate is calculated from measured vapor pressure stabilization with ideal gas assumption of vapour state. Stainless steel particles (spherical, Ø45µm) have been sintered under vacuum condition to form porous tablets of Ø20x 5mm with pore size 2-3 µm. Some of the porous samples have been coated with graphene using freeze-drying-coating technique [2]. Fig :2 presents the comparison of the evaporation rate from graphene-coated PM, an uncoated PM, and from a free surface as a reference. As expected, uncoated PM dramatically reduces the evaporation rate with respect to the free surface case. At the same time, coated PM shows steeper evaporation rate in comparison to uncoated one. This effect could be implemented for enhancement of porous evaporators.

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