Abstract Effective heat dissipation of a persistent surface heat flux is eagerly demanded in a multitude of applications. Such heat dissipation can be accomplished with thin-film evaporation, where metallic wicking structures are developed to effectively spread liquid over a surface to keep it wet during the heat transfer process. Capillary forces, permeability, and wicking thickness are the main properties that determine thin-film spreading and, thus, the evaporation performance. To achieve effective wicking, an aluminum High-Temperature Conductive Microporous Coating (Al-HTCMC) is used. The coating consists of aluminum particles that are brazed onto an aluminum surface. The coating, with different average particle diameters (dp = 11, 24, 66 and 114 µm), is applied over the aluminum plate (50.8 mm × 152.4 mm × 3.3 mm). Distilled water is selected as the working fluid and rate of rise experiments are performed to determine the effective meniscus radius and the permeability of unheated Al-HTCMC surfaces. Evaporation experiments at saturated conditions reveal that nearly zero superheat is needed for evaporation along a large vertical heater with area of 50.8 × 127 mm2. The temperature across the entire surface remains uniform until the dryout heat flux occurs, regardless of particle size at heat flux values up to 1.49 W/cm2 over the entire heater's area. A theoretical model is used to predict the dryout heat flux based on pressure drop through the microporous layer. Experimental results are in good agreement with the prediction model.

中文翻译：

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铝高温导电微孔涂层中水分的毛细蒸发

摘要 在众多应用中迫切需要持久表面热通量的有效散热。这种散热可以通过薄膜蒸发来实现，其中开发了金属芯吸结构以有效地将液体散布在表面上，以在传热过程中保持湿润。毛细管力、渗透性和芯吸厚度是决定薄膜扩散以及蒸发性能的主要特性。为了实现有效的芯吸，使用了铝制高温导电微孔涂层 (Al-HTCMC)。涂层由铜焊在铝表面上的铝颗粒组成。将具有不同平均粒径（dp = 11、24、66 和 114 µm）的涂层涂覆在铝板（50.8 mm × 152.4 mm × 3.3 mm）上。选择蒸馏水作为工作流体并进行上升速率实验以确定有效弯月面半径和未加热的 Al-HTCMC 表面的渗透率。饱和条件下的蒸发实验表明，沿着面积为 50.8 × 127 mm2 的大型立式加热器蒸发所需的过热度几乎为零。整个表面的温度保持均匀，直到出现干燥热通量，而不管整个加热器区域的热通量值高达 1.49 W/cm2 时的颗粒大小如何。理论模型用于基于通过微孔层的压降来预测干涸热通量。实验结果与预测模型吻合较好。