UNS: Experimental and Theoretical Investigation of Thin Film Evaporation in Superhydrophobic-Superhydrophilic Hybrid Micro\Nanotextures

因为液体蒸发从表面带走大量的热量，所以需要快速蒸发。该研究小组将制造新型表面，使薄液膜的蒸发速度比典型的沸腾过程更快。 因此，这些表面能够以非常高的速率去除热量，这在许多工业应用中是需要的。 不仅是研究生，还有来自达拉斯地区的K-12学生都将参与这个项目。与核态沸腾相比，毛细毛细芯吸结构中的薄膜蒸发可以潜在地产生更高的传热速率。 为了进一步增强薄膜蒸发传热，PI建议在电介质上的电润湿（EWOD）的帮助下探索一种新的途径，以在热点表面上装饰的微/纳米多孔双芯结构中启动和维持薄膜蒸发。 PI将首先开发具有微米和纳米级结构的多尺度纹理表面，并对其进行处理，使其具有超疏水性或超亲水性。 EWOD流体操作将用于在表面上产生精确控制的液体体积。 该项目将集中在检测流体弯月面分布和润湿流动动力学，使用微PIV（粒子成像测速仪）在不同的表面结构，以确定在高的热通量和表面纹理对传热率的影响存在的毛细动力学和薄膜厚度的表面纹理的相互依赖性。

Because liquid evaporation takes away a large amount of heat from a surface, rapid evaporation is desirable. The research team will fabricate new types of surfaces from which thin liquid films can evaporate faster than in a typical boiling process. As a consequence, these surfaces enable removing heat at very high rates which is demanded in many industrial applications. Not only graduate students but also K-12 students from the Dallas area will be involved in this project.Thin film evaporation in capillary wicking structures can potentially yield higher heat transfer rates as compared to those of nucleate boiling. To further enhance the film evaporation heat transfer, the PI proposes to explore a novel avenue with the help of electro-wetting on dielectric (EWOD) to initiate and sustain thin film evaporation in micro/nano porous bi-wick structures decorated on hot spot surfaces. The PI will first develop multi-scale textured surfaces with micro- and nano-scale structures with treatments to make them super-hydrophobic or super-hydrophilic. The EWOD fluidic operations will be used to generate precisely controlled liquid volume on the surface. The project will be concentrated on detecting fluid meniscus distributions and wetting flow dynamics, using micro-PIV (particle imaging velocimetry) on different surface structures to determine the interdependency of the surface texturing on the wicking dynamics and thin film thickness in the presence of high heat fluxes and the effect of surface texturing on heat transfer rates.