IMI Interdisciplinary Mathematics InstituteCollege of Arts and Sciences

Micro/Nano-Engineered Interfaces for Two-phase Heat Transfer and Its Roles in Renewable Energy

  • Sept. 1, 2010
  • 2:30 p.m.
  • LeConte 312

Abstract

With the miniaturization of electronic systems and increasing power density, thermal management is one of the most critical sub-systems of many civil and military systems. These systems include the next generation computer chip, high-energy lasers, leading edge of hypersonic plane and electrical propulsion. In the energy sector, 100 W/cm2 is expected from 1000 suns concentration photovoltaic cell (CPV) and 1000 W/cm2 from light-emitting-diode (LED). For extreme high heat flux applications along with size and weight constraints, conventional heat sinks or spreaders become severely inadequate. The micro/nano engineered surfaces or interfaces provide an effective way to promote phase-change heat transfer and hence to develop high performance and compact phase-change heat transfer devices. In this talk, Dr. Li would like to illustrate his fundamental research in this area. For example, Dr. Li has successfully grown metallic nanorods on the copper surfaces by glancing angle deposition (GLAD). Through use of nanorods, the boiling performance was found to be enhanced up to an order of magnitude compared with plain surfaces, which cannot be predicted by classic nucleate boiling theory. New explanation was proposed based on test data and theoretical analysis. In the development of compact phase-change heat transfer devices, flexible thermal ground plane (FTGP), which integrates the state of arts in design, system integration, heat transfer, and micro/nanofabrication, will be discussed as an example in this presentation. FTGP can serve as a stand-alone component or can be embedded in a flexible or rigid substrate for effective thermal management. The FTGP is made hermetic by a nano-scaled alumina coating through atomic layer deposition (ALD). The novel micro/nano wick structures incorporate an ALD hydrophilic coating for the evaporator and assure effective operation under high heat flux conditions.

In this talk, Dr. Chen Li would like to discuss his research activities in the near future. Since tri-phase (solid-liquid-vapor interface) dynamics is the bedrock of phase-change heat transfer theory, advanced energy conversion/storage, microfluidics, thin film technology and self-assemble technology, tri-phase dynamics during the phase change process will be the core of his fundamental research activities. This fundamental research has a wide variety of applications in energy sector. For examples, advanced thermal storage technology is essential to enable 24/7 operation of a concentration solar power (CSP) system, and cost-effective thermal management is critical to promote the reliability and efficiency of high power devices.

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