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王庆明教授学术报告

发布者:         发布时间:2018-07-04 09:10         浏览次数:


报告题目:A Solid-state Refrigeration Based on Electrocaloric Effect: Device and Its Analytical Model
报告人:Dr. Qing-Ming Wang, Professor of University of Pittsburgh

报告时间:201871016:45

报告地点:力学系会议室(南一楼东北角E320

邀请人:胡洪平、胡元太

Abstract: Electrocaloric (EC) cooling technology, which has reversible temperature change of a polarizable material in an adiabatic condition with the application and/or removal of an electric field, exhibits some great advantages for efficient solid-state refrigeration. However, many challenges still exist in EC cooling technology. One of the main challenges is how to control the heat transfer direction. Some of the reported device types require movement of EC material by step motor or fluid media by pump back and forth between heat source and heat sink for controlling heat transfer direction. The other device designs utilize thermal diodes by adjusting their thermal conductivity to control heat transfer direction. Here we propose a solid-state electrocaloric refrigeration device using unimorph beam structure which has temperature change due to EC effect and can be actuated to generate bending deformation due to converse piezoelectric effect. The new device design would eliminate problems of fluid medium loss, friction, high thermal conductivity ratio requirement and external system assistance, etc., existed in the previously reported EC cooling device types. An analytical model is also derived by considering multi-physical phenomenon. The model shows that the temperature change is a combinatorial result from the couplings of thermal, electric and mechanical field in the device.

Biosketch: Dr. Qing-Ming Wang is a professor in the Department of Mechanical Engineering and Materials Science, at the University of Pittsburgh, Pennsylvania. He received the B.S. and M.S. degrees in Materials Science and Engineering from Tsinghua University, Beijing, China, in 1987 and 1989, respectively, and the Ph.D. degree in Materials from the Pennsylvania State University in 1998. Dr. Wang’s primary research interests are in functional materials and devices, microelectromechanical systems (MEMS) and microfabrication; thin film bulk acoustic wave resonators (FBAR), and acoustic wave sensors; and piezoelectric and electrostrictive thin films and composites for transducer, actuator, and sensor applications. Dr. Wang’s research is well funded by US National Science Foundation (NSF), DOE-NETL, ARO, and industry. He has published over 100 papers in international journals and his work has been presented in numerous international conferences. He is the recipient of IEEE-UFFC outstanding paper award in 2006, and MEMS department visiting committee excellent educator award in 2015. He is a member of IEEE, IEEE-Ultrasonics Ferroelectrics and Frequency Control, ASME, and the American Society of Engineering Education (ASEE).