Bourns Hall

Colloquium

Dr. Derek Dunn-Rankin Mechanical and Aerospace Engineering University of California, Irvine PORTABLE POWER SYSTEMS – advanced energy technologies to enhance human autonomy Abstract The lack of portable power is the bottleneck technology currently limiting the performance of autonomous devices. Specifically, enhanced function cellular telephones, portable networks for computation and communication, hand-held or hand-launched robotic devices, exoskeletal systems or powered joints, and artificial internal organs cannot achieve their potential because the appropriate compact, efficient, lightweight power sources do not exist. Miniature combustion engines and fuel cells utilizing condensed phase fuels are two promising examples, respectively, of thermochemical and electrochemical power production strategies that are close to achieving the requisite autonomous power demands. However, current small-scale engines, while achieving extraordinary power densities, are too inefficient to meet energy density expectations. Fuel cells show great promise as an efficient energy source when relatively low power density is demanded, but they cannot yet deliver high peak powers nor respond quickly to variable loads. These challenges are significant, but if overcome the payoff is extraordinary. This talk will delve into some of the fundamental issues and research advances in small scale energy technologies, including comparisons between fuels cells and miniature combustion systems. Biosketch Dr. Derek Dunn-Rankin, Professor in Mechanical and Aerospace Engineering, received his B.S. degree in Mechanical Engineering from the University of California, Santa Barbara (1980), and his M.S. and Ph.D. degrees (1985) from the University of California, Berkeley, with an emphasis in combustion science. He was a post-doctoral researcher at Sandia National Laboratories Combustion Research Facility in Livermore until 1987, when he joined the faculty of Mechanical Engineering at the University of California, Irvine. Dr. Dunn-Rankin has more than 200 technical publications documenting research in droplet and sprays, applications of laser diagnostic techniques to practical engineering systems, and combustion control. For example, he has applied coherent anti-Stokes Raman scattering (CARS) for temperature measurements in droplet flames and engines. He has also used laser-induced fluorescence (LIF) to detect vaporization in droplet stream flames. Professor Dunn-Rankin teaches three senior mechanical engineering design courses, guiding students through the design process in a range of student, industry, and faculty originated projects, and he is currently the UCI Regional Director for CAMP, the California Alliance for Minority Participation, a program designed to increase minority representation in science and technology. Dr. Dunn-Rankin received a National Science Foundation Presidential Young Investigator Award in 1989, the Society of Automotive Engineering Ralph R. Teetor Engineering Educator Award in 1991, and a Fulbright Scholar Fellowship in 1997. Current activities include the design and testing of a miniature liquid-film combustor and applications of electric fields for the active manipulation of sprays and flames. The miniature combustor is designed as a compact power and propulsion source in terrestrial and space applications. The electric field research provides a robust mechanism for controlling flames in applications that range from instability reduction to directing hot products in the absence of gravity. Professor Dunn-Rankin is currently developing a multi-university effort to establish a research center for the development of human compatible, Portable Power Systems. Portable power is a clear technological bottleneck for advancement in machine-assisted human endeavor. Communication systems, augmented reality, and personal robots are all demanding more power than can be conveniently provided in compact, lightweight packages. The goal of the Portable Power Systems Center is develop the next generation devices for providing this power. Thermochemical approaches (e.g., engines) and electrochemical solutions (e.g., fuel cells) have limitations and advantages in different power profile environments, and only through hybrid designs will the necessary breakthrough performance be achieved. Hence, the Center will advance each of these power approaches individually and then create advanced power systems through their combination. Wednesday, November 24, 2004 Bourns Hall A265 10:10 a.m.-11:00 a.m. (Refreshments will be served at 10:00 a.m.)