Droplet and Spray Deposition on Complex Surfaces

液滴对固体表面的冲击在许多工业应用中都存在，如喷漆、喷墨打印和喷雾冷却，已有许多关于水或碳氢化合物液滴对不透水表面的冲击的研究。关于液滴对加热的多孔表面的影响的实验研究要少得多，尽管表面在许多过程中都是多孔的，如木材喷雾、纸张喷墨打印、喷洒系统灌溉土壤和喷雾冷却热的多孔体。液体也可能是复杂的，因为油漆和涂料中使用的配方通常是非牛顿的，并且含有表面活性剂、颗粒或其他改变其性能的添加剂。这项研究将研究复杂表面的液滴和喷雾的相互作用，以及复杂液体的喷雾沉积。将进行的一些项目包括： 液滴对多孔材料的影响：液滴对夹层多孔基材切片的影响将使用高速摄像机进行记录。将开发液体吸收到孔隙中的模型。 液滴在多孔表面上的蒸发和沸腾：水滴和碳氢化合物将沉积在加热的多孔金属板上，并测量它们的重量变化，以确定液体蒸发的速度。将开发表面冷却模型。 复杂表面的喷雾冷却：将建立一个喷雾设备，其中的水喷雾冷却加热的复杂表面，如球体或圆柱体阵列。将开发模型来预测液体在表面内的渗流和蒸发速度。 复合流体的喷雾沉积：复合流体含有片状或粉末等颗粒，可改变涂料和涂层的性能。实验将在含有颗粒的聚合物流体中进行，并将薄片喷洒到表面并固化，使其变硬。涂层的性能(硬度、颜色变化)将被测量，并与颗粒的浓度和取向有关。 我们将从这项研究中获得的见解将在许多不同领域发挥重要作用，并补充我们与工业伙伴在喷雾冷却和喷涂层领域所做的工作。这项研究的结果将： 增进我们对液滴-表面相互作用的理解，这一领域已经研究了一个多世纪，但仍然是一个非常活跃的研究领域，有许多悬而未决的问题。 改进多孔和不规则形状表面的快速冷却方法。例子包括电子冷却、核电站的安全系统以及带有喷水灭火系统的灭火。 帮助更好地配制涂层材料，优化有机涂层的性能，将缺陷降至最低，并获得良好的机械和光学性能。

Droplet impact on solid surfaces occurs in many industrial applications such as spray painting, ink-jet printing and spray cooling and many studies have been done of water or hydrocarbons droplet impact on impermeable surfaces. Far fewer experimental studies have carried out on the impact of droplets on heated porous surfaces, even though surfaces are porous in many processes such as spray coating of wood, ink-jet printing on paper, soil irrigation by sprinkler systems and spray cooling of hot, porous bodies. Liquids can also be complex since formulations used in painting and coating are frequently non-Newtonian and contain surfactants, particles, or other additives that modify their properties. This research will study both the interaction of droplets and sprays with complex surfaces, and spray deposition of complex liquids. Some of the projects to be undertaken are: Impact of droplets on porous materials: The impact of a droplet on slices of porous substrates sandwiched will be recorded using a high-speed video camera. Models will be developed of liquid absorption into pores. Evaporation and boiling of droplets on porous surfaces: Droplets of water and hydrocarbons will be deposited on heated porous metal plates and their change in weight measured to determine the rate of liquid evaporation. Models of surface cooling will be developed. Spray cooling of complex surfaces: A spray apparatus will be built in which water sprays quench heated, complex surfaces such as arrays of spheres or cylinders. Models will be developed to predict the rate of liquid percolation and evaporation within the surface. Spray deposition of complex fluids: Complex fluid contain particles such as flakes or powders that modify the properties of paints and coatings. Experiments will be done in polymeric fluids containing particles and flakes are sprayed onto a surface and cured so that they harden. Properties of coatings (hardness, colour variation) will be measured and related to the concentration and orientation of particles. The insights we will gain from this research will be important in a number of different areas and complement the work that we are doing with industrial partners in the areas of spray cooling and of spray coating. The results of this research will: Enhance our understanding of droplet-surface interactions, an area that has been studied for over a century but is still a very active area of research with many unanswered questions. Improve methods of rapidly cooling surfaces that are porous and irregular shaped. Examples include electronic cooling, safety systems in nuclear plants, and fire suppression with sprinkler systems. Help better formulate coating materials and to optimize the properties of organic coatings to minimize defects and obtain good mechanical and optical properties.