“Practice Your Scales! Thermal, Energy, and Bio Nanomaterials for Fast Processes” by Prof. Timothy S. Fisher, Purdue University

Abstract:

The theory of energy and charge transport is a century old, yet classical and quantum size effects have been exploited usefully in practical materials only for the past two decades, and often with a modest level of success in practice. Many of the remaining challenges involve problems of time and length scales – e.g., faster energy transport processes enabled by new materials that can be manufactured economically at human scales. Success in the large-scale adoption of nanomaterials, with their prevalence of interfaces, will likely depend on deeper fundamental understanding of both interfacial transport in assemblies of nanomaterials over wider time scales and high-throughput manufacturing processes over larger length scales in order to tune their performance and engineer them for desired properties in real applications. For example, individual carbon nanotubes possess extremely high axial thermal conductivity, yet when placed in a composite matrix, the effective thermal properties are quite ordinary. For high-performance cooling applications, single-phase convection is a limited option because of its inability to dissipate ultra-high thermal loads, thus constraining the performance of the host system. With these challenges in mind, this presentation will consider how nanomaterials can be exploited at appropriate engineering scales to improve the performance of realistic thermal and energy storage technologies, particularly those requiring rapid transient response. Carbon nanomaterials for use in fast-charging and discharging electrochemical energy storage devices offer particular promise as scalable, high-performance electrodes, and similar structures show outstanding sensitivity to biological analytes. Moreover, the microstructure of granular assemblies of battery cathode materials will be shown to have a profound effect on charge/discharge speed. As another example, a tunable cooling technology befitting fast transient thermal events will be described. In this system, the rapid depressurization of the working fluid triggers coincident flash boiling and desorption events, thereby achieving very high cooling rates for short periods of time. We anticipate that this technology, when properly controlled, will achieve instantaneous peak cooling efficiencies surpassing those other advanced cooling systems. The presentation will close with a discussion of opportunities to ‘practice our scales’ further in order to enable cost-effective, large-scale production of these technologies.

Biosketch:

Timothy S. Fisher is the James G. Dwyer Professor of Mechanical Engineering at Purdue University. He received Ph.D. and B.S. degrees in Mechanical Engineering from Cornell University in 1998 and 1991, respectively, and joined the Purdue’s School of Mechanical Engineering and Birck Nanotechnology Center in 2002 after several years at Vanderbilt University. In 2008 he was a Visiting Professor in the Chemistry and Physics of Materials Unit of the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR, Bangalore, India), and he now holds the position of Adjunct Professor in the International Centre for Materials Science at JNCASR and co-directs the JNCASR-Purdue Joint Networked Centre on Nanomaterials for Energy. From 2009 to 2011, he served as a Research Scientist at the Air Force Research Laboratory’s newly formed Thermal Sciences and Materials Branch of the Materials and Manufacturing Directorate. Prior to his graduate studies, he was employed from 1991 to 1993 as a design engineer in Motorola’s Automotive and Industrial Electronics Group. His research has included efforts in simulation and measurement of nanoscale heat transfer, coupled electro-thermal effects in semiconductor and electron emission devices, nanoscale direct energy conversion, molecular electronics, microfluidic devices, hydrogen storage, and computational methods ranging from atomistic to continuum scales.

Date/Time:
Date(s) - Sep 22, 2016
11:00 am - 12:00 pm

Location:
6764 Boelter Hall (Rice Room)
580 Portola Plaza Los Angeles California 90095