Transport in Single and Multiphase Flows with and without Phase Change

该提案涉及多相系统及其在工程实践中的应用。考虑了多相流的两个主要推力：内部流动和外部流动。第一个重点是了解微尺度和微尺度系统中的两相流传热及其在热交换器和微电子冷却中的应用。我们考虑了许多经典的内部流动中的两相流动问题，如分段或泰勒流动以及使用纳米流体的分散液滴/颗粒流动。两个主要目标是更好地了解热传递机制和开发可用于设计有效的热管理解决方案的可靠的预测模型。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。喷雾结冰主要是由于波浪/容器的相互作用，导致大量分散的水滴撞击寒冷的表面。海洋结冰是中小型海洋船舶认真考虑的问题。由于海水是咸水，影响液滴冻结的方式与淡水不同，因此情况更加复杂。如果冰块变大或表面结冰，船舶安全就会受到影响。根据目前的建议，我们正在研究撞击水滴提前冻结的问题，以更好地了解冰粘着，找到推迟结冰开始的方法，找到有效防止大规模结冰形成的方法，并考虑使用实时测量系统来开发早期预警系统。这两种研究推力都涉及多相流换热，但一种是无相变的内部流动，另一种是有相变的外部流动。由于对当前申请中提出的主题的成功追求，新技术的巨大潜力存在。技术开发的一个潜力是开发抑制或减少结冰的特殊涂层。另一项潜在的技术是开发一种仪器系统，以主动测量喷雾流量和结冰。本建议书提供了8名HQP的培训机会。这些HQP将在热-流体领域发展广泛的高级分析技能，使他们能够在许多行业工作，如汽车、微电子的热管理、海洋安全、水力发电和输电，以及无数其他行业。

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.