Time£º13:30 to 15:00 , Tuesday£¬July 19th
Place£ºF210, School of Mechanical Engineering
Speaker£ºProf. Zhuomin Zhang
Host£ºProf. Zhao Changying (Institute of Engineering Thermophysics)
Near-field radiative heat transfer holds promise forhigh-throughputthermophotovoltaic devices, nanomanufacturing, thermal imaging, vacuum thermal rectifiers, and electroluminescent refrigeration, especially when the vacuum gap separating the structures is reduced to nanoscale distances. Recently, we have developed an experimental facility and measured near-field radiative heat transfer between parallel doped-Si plates, with surface areas of 1 cm by 1 cm, separated by vacuum at submicron distances from about 800 nm down to 200 nm. We have numerically studied the use of tungsten nano-gratings to enhance near-field thermophotovoltaic devices. It is found that the power output can be increased by 40% while improving the efficiency from 29.9% to 32.0% with a selected grating emitter as compared to the case of a flat tungsten emitter. Furthermore, we have theoretically shown that, by operating the device in the near-field regime with a vacuum gap down to 10 nm, photon tunneling through evanescent waves can increase the electroluminescent refrigeration rate by 2000-fold over the far-field scenario. In this seminar, I will present the fundamental theory, numerical and experimental findings, as well as future challenges.
Professor Zhuomin Zhang earneda Ph.D. degree from MIT and worked at NIST and University of Florida prior to joining Georgia Tech, where he currently is a professor in mechanical engineering. He received his B.S. and M.S. degrees from the University of Science and Technology of China (Hefei). Heis a Fellow of the American Association for the Advancement of Science (AAAS), the American Society of Mechanical Engineers (AMSE), and the American Physical Society (APS). Professor Zhang¡¯s research interests are in micro/nanoscale heat transfer especially thermal radiation for energy conversion and temperature measurement. He has written a book on Nano/Microscale Heat Transfer, co-authored over 160 journal papers, and given over 300 invited and contributed presentations. His former students have established independent careers at major universities or industry in the United States, China (mainland and Taiwan) and South Korea. In addition, Professor Zhang has supervised many visiting scholars, postdoctoral fellows and undergraduate student researchers. Hecurrently serves asan associate editor of the Journal of Heat Transfer andJournal of Quantitative Spectroscopy & Radiative Transfer.He served as the Program Chair of the ASME 3rd Micro/Nanoscale Heat & Mass Transfer International Conference (Atlanta, March 2012), Chair of the 2nd International Workshop on Nano-Micro Thermal Radiation (Shanghai, June 2014), and General Chair for the ASME 5rd Micro/Nanoscale Heat & Mass Transfer International Conference (Singapore, January 2016).Professor Zhang was a recipient of the 1999 Presidential Early Career Award for Scientists and Engineers (PECASE) and the 2015 ASME Heat Transfer Memorial Award (in the Science category). He has also wona number ofteaching, research, and best paper awards.