Seminar: Interfacial Engineering for Efficiency Enhancements in Energy-Water-Food

Abstract

Thermal-fluid-interfacial interactions are ubiquitous in multiple industries including Energy, Water, Agriculture, Food Processing, Transportation, Buildings, Medical, and Consumer Packaging. In this talk, we show how surface/interface chemistry and morphology can be engineered across multiple length scales ranging from atomic to macroscale for significant efficiency enhancements in a wide range of thermal-fluid processes. We study the thermodynamics and wetting dynamics of droplets as a function of surface texture and surface energy and establish various wetting regimes and conditions for wetting transitions. We show how breaking symmetry can fundamentally alter drop impact hydrodynamics and reduce the contact time of bouncing drops below previously established theoretical limits. This approach can have implications for controlling transport phenomena involving impacting droplets, for example in icing.  We then present the behavior of surfaces under phase change, such as condensation, and freezing at nano, micro and macroscales, and find that their non-wetting properties can be compromised due to nucleation within texture features. Based on these insights, we introduce lubricant-impregnated surfaces that can exhibit remarkable slippery properties and robustness when compared to air-pocket based superhydrophobic surfaces. We discuss unconventional contact line morphology, cloaking states, thermodynamics and hydrodynamics, phase transitions such as condensation and crystallization and show how surfaces can be designed to be slippery to even complex fluids such as ketchup, mayonnaise, blood, paints, and crude oil. Finally, we discuss the influence of atomic and electronic structure on interfacial wetting interactions and use these fundamental insights to develop hydrophobic ceramic materials to address the critical need for robustness. Manufacturing and scale-up approaches, robust materials, entrepreneurial efforts to translate these surface technologies into useful products, and applications of nanoengineered surfaces in various energy, water, food, consumer packaging, medical, and transportation industries, and will be discussed.

About the Speaker

Kripa K. Varanasi is an Associate Professor in the Department of Mechanical Engineering at MIT. He received his B.Tech from IIT, Madras, India and his MS (ME and EECS) and Ph.D from MIT.  Prior to joining MIT, Prof. Varanasi was a lead research scientist and project leader in the Energy & Propulsion and Nanotechnology programs at the GE Global Research Center, Niskayuna, NY, and was the PI for the DARPA Advanced Electronics Cooling program. The primary focus of his research is in the development of nano-engineered surface, interface, and coating technologies that can dramatically enhance performance in energy, water, agriculture, transportation, buildings, and electronics cooling systems. He is enabling this approach via interdisciplinary research focused on a nanoengineered surfaces and interfaces, thermal-fluid science and new materials discovery combined with scalable nanomanufacturing. His work spans various interfacial thermal-fluid phenomena including wetting and adhesion, phase transitions (condensation, boiling, freezing, crystallization), nanoscale thermal and fluidic transport, separation, surface chemistry, multiscale surface manufacturing, and synthesis of inorganic bulk and nanoscale materials. Prof. Varanasi has filed more than 50 patents in this area. He has received the NSF Career Award and DARPA Young Faculty Award. He is active in entrepreneurship and has co-founded two companies LiquiGlide and DropWise for translating the technologies from his lab to market. He received the audience choice award at the MIT 100K and 100K Diamond prize at MassChallenge Entrepreneurship competitions. Time and Forbes Magazines have named LiquiGlide one of the Best Inventions of the Year. He was most recently awarded the Outstanding Young Manufacturing Engineer award by the Society of Manufacturing Engineers and Bergles-Rohsenow Heat Transfer Award by ASME.

More details at varanasi.mit.edu

Hosted by Professor Bharat Bhushan.