论文标题
在平面和圆柱之间的角落中液体的毛细管上升和蒸发：吸收到纳米纤维垫涂层的模型
Capillary rise and evaporation of a liquid in a corner between a plane and a cylinder: A model of imbibition into a nanofiber mat coating
论文作者
论文摘要
用多孔涂层进行表面润湿与多种技术应用有关，例如打印技术和增强传热。在覆盖有多孔层的表面上的液体的吸收和蒸发负责在滴效果冷却过程中的冷却效率显着提高，并在此类表面上流动沸腾。到目前为止，还没有可靠的模型可以预测吸收的动力学，并在带有多孔涂层的表面上蒸发。在这项工作中，我们考虑了在纳米纤维垫覆盖的基材上吸收的可能机制之一。这是毛细管压力驱动的流动，该流动流在其扁平基板和附着的纤维之间形成的角落。液体占据的横截面的形状和面积以及沿流动方向变化的毛细管压力。开发了同时吸收和蒸发的理论/数值模型，其中考虑了粘度，表面张力和蒸发。在过程开始时，吸收长度与时间的平方根成正比，与卢卡斯·瓦什伯恩（Lucas-Washburn Law）一致。随着蒸发的影响显着，吸气率降低。将模型预测与实验数据进行比较，以吸收水 - 乙醇混合物到纳米纤维垫涂层中。
Wetting of surfaces with porous coating is relevant for a wide variety of technical applications, such as printing technologies and heat transfer enhancement. Imbibition and evaporation of liquids on surfaces covered with porous layers are responsible for significant improvement of cooling efficiency during drop impact cooling and flow boiling on such surfaces. Up to now, no reliable model exists which is able to predict the kinetics of imbibition coupled with evaporation on surfaces with porous coatings. In this work we consider one of possible mechanisms of imbibition on a substrate covered by a nanofiber mat. This is the capillary pressure-driven flow in a corner formed between a flat substrate and a fiber attached to it. The shape and the area of the cross-section occupied by the liquid as well as the capillary pressure change along the flow direction. A theoretical/numerical model of simultaneous imbibition and evaporation is developed, in which viscosity, surface tension and evaporation are taken into account. At the beginning of the process the imbibition length is proportional to the square root of time, in agreement with the Lucas-Washburn law. As the influence of evaporation becomes significant, the imbibition rate decreases. The model predictions are compared with experimental data for imbibition of water-ethanol mixtures into nanofiber mat coatings.
