Wed, Jan 27, 2021 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Speaker: Patricia Weisensee, Washington University in St. Louis
Talk Title: Let Droplets Drop the Temperature: Fluids-Based Thermal Management
Abstract: The coupling of fluid dynamics and heat transfer dominates many environmental and industrial processes, including the natural water cycle (evaporation from lakes and oceans, condensation in clouds), electronics thermal management, power generation, and materials manufacturing and processing. In this talk I will highlight two such phenomena: Condensation and evaporation, and advanced thermal management solutions using room-temperature liquid metals. I will focus on droplets, which are omnipresent in our daily lives, and provide the ability to actively manipulate the flow of matter and heat.
The major focus of my lab lies on understanding phase change phenomena, with a special emphasis on vapor-liquid (condensation) and liquid-vapor (evaporation or boiling) heat transfer. In this talk, I will show that water condensation on so-called lubricant-infused surfaces (LIS) can have up to 10-fold increased water collection efficiency due to an extremely high droplet mobility compared to bare metal surfaces. Lubricant wetting ridges surrounding droplets introduce an attractive capillary force, leading to self-propelled and gravity-independent droplet motion, which efficiently clears the surface for frequent re-nucleation. On the other hand, wettability-patterning a surface and thus restricting the mobility of droplets can be advantageous during evaporation. I will show that the alteration of convection within the droplets and localized evaporation-enhancement at the contact lines can effectively increase the overall heat transfer rates. In the last part of this talk I will introduce an ongoing project in collaboration with NASA, where my research group is developing a passive and compact thermal heat switch. I will present some preliminary results and highlight the challenges associated with using gallium-based liquid metals.
Biography: Patricia Weisensee is an Assistant Professor of Mechanical Engineering and Materials Science at Washington University in St. Louis (WashU). She earned her PhD in Mechanical Engineering from University of Illinois at Urbana-Champaign in 2016. She received a Diplom-Ingenieur in Mechanical Engineering from TU Munich in 2013 and also holds a M.S. in Materials Sciences from University of Illinois at Urbana-Champaign (2011). For her Diplom thesis on condensing steam bubbles in sub-cooled flow, Dr. Weisensee received the Siemens Energy Award 2014. She is an alumna of the German National Academic Foundation (Studienstiftung des deutschen Volkes), Germanys largest, oldest, and most prestigious scholarship foundation.
At WashU, Dr. Weisensee leads the Thermal Fluids Research Group, which focuses on understanding the interplay of fluid dynamics and heat transfer of droplets and other multi-phase systems. Practical applications of interest are phase change heat transfer for thermal management, thermal storage, and water harvesting, metallic additive manufacturing, and droplet interactions with natural systems. To fundamentally study these thermal-fluidic interactions, her group combines multiple experimental techniques, such as high-speed optical and infrared (IR) imaging, interferometry, confocal fluorescence microscopy, and conventional heat transfer measurements. Dr. Weisensee is a very recent recipient of the NSF CAREER award and currently also holds a 3-year NSF research award to study nucleation and condensation of water on lubricant-infused surfaces (LIS). She was awarded the ACS Petroleum Research Fund Doctoral New Investigator grant to study the pore-scale interactions between fluid flow and heat transfer for oil-water emulsion flow through porous media, and received the prestigious NASA Early Career Faculty Award to develop a passive and compact thermal heat switch to be used on satellites and robots during lunar missions. Recently, Dr. Weisensee also received the 2020 ASME ICNMM Outstanding Early Investigator Award and 2020 Emerson Excellence in Teaching award.
Host: AME Department
More Info: https://usc.zoom.us/j/97141292209
Location: Online event
WebCast Link: https://usc.zoom.us/j/97141292209
Audiences: Everyone Is Invited
Contact: Tessa Yao
Event Link: https://usc.zoom.us/j/97141292209