Faculty Candidate Seminar
Title: |
Optimizing Liquid-Gas Interfacial Transport for a Sustainable Future |
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Speaker: |
Dr. Zhengmao Lu |
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Affiliation: |
Massachusetts Institute of Technology |
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When: |
Monday, January 31, 2022 at 1:00:00 PM |
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Where: |
MRDC Building, Room 4211 |
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Host: |
Peter Loutzenhiser | |
Abstract Liquid-gas interfacial transport plays a central role in 70% of the world’s electricity generation, 30% of global desalination, most heating and cooling systems, and all gas-evolving electrochemical reactions. Fundamental understanding of interfacial transport, which can broadly impact energy and water applications, has been limited by the difficulty of experimentally isolating and characterizing the interfacial thermal resistance. In the first part of my talk, I will discuss how we overcame this challenge and elucidated fundamental phase change kinetics with a specially designed ultrathin nanoporous membrane. This configuration allowed us to show a unified relationship for evaporation under different working conditions and subsequently provide a general figure of merit for phase change systems. In the second part of my talk, I will discuss how we translate the obtained understanding into performance enhancement in practical applications leveraging novel engineered materials. For electronics cooling, we created a membrane-based hierarchical evaporator and demonstrated a record pure evaporation heat flux for dielectric fluids. More importantly, our design enabled a new paradigm for phase change heat transfer, favoring low surface tension fluids rather than water. For thermal management of buildings and perishable goods, we invented hydrogel-aerogel bilayer structures which achieves cooling with evaporation while resisting environmental heating. Consequently, we extended the cooling time by 400% compared to the conventional single layer design. Further, we realized simultaneous evaporative and radiative cooling by optimizing the optical properties of the cooling architecture. We demonstrated 300% daytime ambient cooling power enhancement over pure radiative cooling and showed the significant benefit of our hybrid cooling approach under a wide range of climate conditions. Overall, combining fundamental interfacial transport physics with novel materials and interface engineering presents unique opportunities for innovations toward more sustainable energy and water technologies. |
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Biography Zhengmao Lu is a postdoctoral scholar advised by Prof. Jeffrey Grossman in the Department of Materials Science and Engineering at MIT. Prior to this appointment, he obtained his Ph.D. in Mechanical Engineering at MIT, advised by Prof. Evelyn Wang. His Ph.D. thesis focused on establishing modeling frameworks and experimental platforms to elucidate liquid-gas interfacial transport during phase change. Currently, Zhengmao is creating novel passive cooling solutions for buildings, food, and pharmaceutical products and engineering natural carbonaceous materials for industrial separation processes. Zhengmao is a recipient of the Keck Travel Award in Thermal Sciences and the Wunsch Foundation Silent Hoist and Crane Award for Outstanding Graduate Research from MIT Mechanical Engineering. |
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Notes |
Please join virtually via https://bluejeans.com/201981017/6841 |
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