Transport in Single and Multiphase Flows with and without Phase Change

该方案涉及多相系统及其在工程实践中的应用。考虑了多相流的两种主要推力：内部流和外部流。第一个推力涉及理解在热交换器和微电子冷却应用的微型和微型系统中的两相流传热。我们考虑了一些经典的两相流问题在内部流动，如分段或泰勒流动和分散液滴/颗粒流动使用纳米流体。两个主要目标是更好地理解传热机制，并开发可靠的预测模型，用于设计有效的热管理解决方案。这些解决方案包括用于微电子冷却的新型冷却技术和家用水的太阳能热加热。在第二个推力中，我们考虑了海洋喷雾结冰问题。喷雾结冰的发生主要是由于波浪/容器相互作用导致大量分散的水滴撞击冷表面。对于中小型船舶来说，海冰堆积是一个严重的问题。由于海水含盐，影响液滴冻结的方式与淡水不同，因此情况更加复杂。如果积冰变大或表面结冰，则会危及船舶安全。在目前的建议下，我们正在研究撞击液滴的早期冻结，以更好地了解冰的粘附，找到一种方法来延迟冰的开始，找到一种方法来有效地防止大冰的形成，并考虑实时测量系统来开发预警系统。这两个研究重点都涉及多相流传热，尽管一个是针对无相变的内部流动应用，另一个是针对有相变的外部流动应用。由于对当前应用中提出的主题的成功追求，新技术存在巨大的潜力。技术发展的一个潜力是开发能够抑制或减少冰形成的特殊涂层。另一项潜在的技术是开发一种仪器系统来主动测量喷雾通量和冰的增加。本提案提供了8名HQP的培训机会。这些HQP将在热流体领域发展广泛的高水平分析技能，使他们能够在汽车，微电子热管理，船舶安全，水力发电和输电等众多行业中工作。

The proposal deals with multiphase systems and applications in engineering practice. Two major thrusts of multiphase flow are considered: internal flows and external flows. The first thrust deals with understanding two phase flow heat transfer in micro-scale and mini-scale systems with applications in heat exchangers and microelectronics cooling. We consider a number of classic two phase flow problems in internal flow such segmented or Taylor flows and dispersed droplet/particle flows using nanofluids. Two primary goals are to better understand the heat transfer mechanisms and to develop reliable predictive models which can be used to design effective thermal management solutions. These solutions include novel cooling technology for micro-electronics cooling and solar thermal heating of domestic water. In the second thrust we consider marine spray icing issues. Spray icing occurs primarily due to wave/vessel interaction leading to massive amounts of dispersed water droplets impinging on cold surfaces. Marine ice accretion is a serious consideration for small and medium sized  marine vessels. It is further complicated because the seawater is saline which affects droplet freezing in a different manner than fresh water. Vessel safety is compromised if ice accretion becomes large or if surfaces become icy. Under the current proposal we are examining the early onset of freezing of impinging droplets, to better understand ice adhesion, find a means to delay the onset of ice accretion, find a means to effectively prevent large ice accretions from forming, and give consideration to real time measurement systems to develop an early warning system. Both research thrusts involve multiphase flow heat transfer, though one is for internal flow applications with no phase change and the other is external flows with phase change. Great potential for new technology exists as a result of the successful pursuit of the topics proposed in the current application. One potential for technology development is the development of special coatings that inhibit or reduce ice formation. Another potential technology is the development of an instrumentation system to actively measure spray fluxes and ice accretion. Training opportunities for 8 HQP are available in this proposal. These HQP will develop extensive high level analysis skills in the thermal-fluid field allowing them to work in a multitude of industries such as automotive, thermal management of microelectronics, marine safety, hydroelectric generation and transmission, and countless others.