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MEAM Seminar: “Microdevices Enabled by Rarefied Flows”
February 4 at 10:30 AM - 12:00 PM
In this talk we will review emerging applications of rarefied gas dynamics for microscale sensing, actuation and power generation. Performance of conventional fluidic devices such as pumps, combustors and heat engines decreases at the microscale due to greater viscous and heat transfer losses. Unconventional micro/nanodevices exploit the tight coupling between non-equilibrium gas, liquid and solid-state transport and electromagnetic phenomena to overcome these limitations. We consider three distinct MEMS based on i) very high thermal gradients; ii) increased capillary forces; iii) high electric fields. The first example is Microscale In-Plane Knudsen Radiometeric Actuator (MIKRA) that applies thermostress convection to achieve actuation and control of gas-phase transport by temperature gradients and offers novel methods for gas sensing, pumping, and species separation. In macroscale systems, the operating temperatures necessary to generate significant flow actuation by thermostress convection are prohibitively high. For microdevices, thermal gradients on the order of 107 Kelvin per meter could be achieved, allowing these effects to be exploited. Another examples is Film Evaporation MEMS Tunable Array (FEMTA), a micropropulsion technology that works on microscale effects of surface tension, hydrophobicity, and thin film boiling to create highly tunable thrust using ultra pure water as propellant for attitude control and maneuvering of small satellites and deployable space structures.
Professor, Department of Aeronautics and Astronautics & Department of Chemical Engineering, Purdue University
Alina Alexeenko is a professor of Aero & Astronautics and Chemical Engineering at Purdue. She is also an associate dean for undergraduate education at College of Engineering. She received her PhD in Aerospace Engineering from Pennsylvania State University in 2003 and was a WiSE fellow at the University of Southern California prior to joining Purdue as an assistant professor in 2006. Her research is in micropropulsion, high-altitude aerothermodynamics, microsystems and vacuum technology. Dr. Alexeenko received 2011 NSF CAREER, 2013 C.-T. Sun Excellence in Research awards and is a 2015 inductee in Purdue Innovators Hall of Fame. She leads research programs on developing new small spacecraft technologies and is a founding co-Director of Advanced Lyophilization Technology Hub – LyoHUB, an industry-university consortium comprised of 24 companies across the entire value chain in biopharmaceutical manufacturing working on new technologies and standards for vacuum freeze-drying/lyophilization.