Abstract
This paper presents the modeling of mechanical loss in Gas foil bearings (GFBs) that support a Permanent magnet (PM) motor. This paper also presents parametric studies to evaluate the effects of carrier harmonics in the input current and cooling-air supply on the motor thermal performance. Because GFB functions not only as a heat source but also as a thermal resistance, we model it as an equivalent element comprising a thermal conductor. The calculation of the bearing loss from the hydrodynamic analysis shows one-order-ofmagnitude smaller values than the electromagnetic losses, thus indicating a slight effect on the PM motor performance. A case study shows the strong effects of the carrier harmonics and cooling-air supply on the motor thermal performance at a rotor speed of 35 krpm. A further study at an increased speed of 60 krpm shows significant increases in the motor losses and temperatures.
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Kyuho Sim received the M.S. degree in mechanical engineering from KAIST, Daejon, Korea, in 2002 and Ph.D. degree in mechanical engineering from Texas A&M University, College Station, TX, in 2007. He joined Samsung Advanced Institute of Technology, Suwon, Korea, in 2007, and Korea Institute of Science and Technology, Seoul, Korea, in 2010. In 2013, he joined the Department of Mechanical System Design Engineering at Seoul National University of Science and Technology as an assistant professor. His research interests are lying on sustainable, efficient energy conversion and harvesting systems such as micro turbine generators, Stirling engine generators, vibro wave convertors, etc.
Yong-Bok Lee, KIST, Principal researcher and Professor, received his Ph.D. (1997) degrees in Mechanical Engineering for the Hanyang University. He charged head of energy mechanics center in KIST from 2007 to 2011. And he is a professor of UST. His main research topic is a hydrodynamic bearing and its application from the beginning of 1990. Dr. Lee’s current research issues are controllable tribo-elements such as a hybrid bearing (HFMB; Air foil bearing and Active magnetic bearing) and ball bearings operated cryogenic condition for turbo pump of LRE (liquid rocket engine).
Seok-Myeong Jang received the B.S., M.S., and Ph.D. degrees in electrical engineering from Hanyang University, Seoul, Korea, in 1976, 1978, and 1986, respectively. He joined Chungnam National University, Daejeon, Korea, in 1978-2014. Currently he is an Emeritus Professor and a CEO of SEMS Hightech Engineering. His research interests include Special Electric Machines (SEMS) design and analysis for high-speed motor/generator system, magnetic levitation vehicle, and renewable energy system, such as wind power generator and flywheel energy storage.
Tae Ho Kim received the B.S. and M.S. degrees in mechanical engineering from Hanyang University, Seoul, Korea, in 2000 and 2002, respectively, and the Ph.D. degree in mechanical engineering from Texas A&M University, College Station, TX, in 2007. In 2009, he joined Korea Institute of Science and Technology, Seoul, Korea, and worked on the development of oil-free rotating systems with high power density. In 2012, he joined the School of Mechanical Systems Engineering, Kookmin University as an assistant professor. His main research fields are gas/fluid film bearing analysis and performance identification, and structural/rotor dynamics in micro/macro turbomachinery systems.
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Sim, K., Lee, YB., Jang, SM. et al. Thermal analysis of high-speed permanent magnet motor with cooling flows supported on gas foil bearings: part II - bearing modeling and case studies. J Mech Sci Technol 29, 5477–5483 (2015). https://doi.org/10.1007/s12206-015-1149-z
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DOI: https://doi.org/10.1007/s12206-015-1149-z