Transport in Single and Multiphase Flows with and without Phase Change

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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.