Development of a Designer Fluid for Phase Change Heat Transfer in Different Materials

CBET 1336896PI：Catton这个项目的目标有两个：1)了解足以开发设计者流体的无机水溶液的化学组成。对于特定的热传递应用，以及2)建立这种设计者流体的能力，以增强要在其中使用它的相变设备(热管、回热器和/或热虹吸管)中的热传递。作为项目的第一部分，对化学的了解将被量化，以确定化学成分的类型和数量的影响。将开发一个各种应用和建议化学成分的资料库。需要什么来钝化各种材料，将混合物的成分及其摩尔分数与钝化、亲水性、表面沉积和微观结构联系起来。该项目的第二部分是量化设计流体的容量，以增强使用该流体的设备中的热传递。材料的沉积和微孔涂层的结构与混合物的化学、pH和温度之间的关系将得到发展。热传递将与组分的数量和类型及其在表面构建微孔涂层的能力以及表面微结构的亲水性和毛细管有关。这样的设计师液对各种类型的芯吸效果的影响将完成该项目。当涉及到相变时，水是最好的换热流体之一，因为它具有最高的蒸发热。不幸的是，水也是一种很好的氧化剂，会导致腐蚀，如果是金属，会产生氢气，这会严重降低换热性能。目前，水只能与铜等金属一起使用。在这项工作中，一种新型的无机水溶液被开发出来，与铝和其他材料的热管和热虹吸管一起使用，可以将换热性能提高多达两倍。将解释负责钝化器件材料内部和防止产生不可冷凝气体(NCG)的化学反应。在一系列不同的材料中，能够使用与水具有同等或更好的传热性能的相变换热流体，将对发电、工艺和电子行业的许多方面以及我们收集废热的能力产生重大影响。

CBET 1336896PI: CattonThe project goals are twofold; 1) yield an understanding of the chemistry of an inorganic aqueous solution that is sufficient to develop a ?designer fluid? for a particular heat transfer application and 2) establish the ability of such a designer fluid to enhance heat transfer in the phase change device (heat pipes, recuperators, and/or thermosiphons) within which it is to be used. The understanding of the chemistry, the first part of the project, will be quantified to establish the impact of the type and amount of the chemical constituents. A library of various applications and suggested chemical constituents will be developed. What is needed to passivate various materials, to relate the mixture constituents and their molality to passivation, hydrophilicity, surface deposition and microstructure will be established. The second part of the project is to quantify the capacity of a designer fluid to enhance heat transfer in the device in which it is to be used. A correlation between the deposition of material and construction of the micro-porous coatings to the chemistry, pH and temperature of the mix will be developed. The heat transfer will be related to the amount and type of constituents and their capacity to construct micro-porous coatings on a surface and to the hydrophilicity and capillarity of the surface microstucture. The impact of such a designer fluid on the effectiveness of various types of wicking will complete the project. Water is one of natures best heat transfer fluids when phase change is involved because it has the highest heat of evaporation. Unfortunately water is also a good oxidizer and can lead to corrosion and, if a metal, hydrogen production that can seriously degrade the heat transfer performance. Presently, water can only be used with metals like copper. In this work, a novel, inorganic aqueous solution is developed for use with aluminum and other material heat pipes and thermosiphons that will improve the heat transfer performance by as much as a factor of two. The chemical reactions responsible for passivating the device material interior and preventing generation of non condensible gases (NCG) will be explained. Being able to use a phase change heat transfer fluid that has the equivalent or better heat transfer performance than water in a range of different materials will have a significant impact on many aspects of the power generation, process and electronics industries and our ability to harvest waste heat.