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Abstract
Issue Title: 2015 International Conference on Thermoelectrics. Guest Editors: Jihui Yang, Matt Beekman, Donald Morelli, James Salvador, David Singh, Hsin Wang, Emmanuel Guilmeau, Juri Grin, Bertrand Lenoir, Xinfeng Tang, Wenqing Zhang, Chunlei Wan, TieJun Zhu, Ryoji Funahashi, Takao Mori, Tsunehiro Takeuchi, Sabah Bux
Gas foil bearings have become widespread covering the applications of micro-turbines, motors, compressors, and turbocharges, prevalently of small size. The specific construction of the bearing, despite all of its advantages, makes it vulnerable to a local difference in heat generation rates that can be extremely detrimental. The developing thermal gradients may lead to thermal runaway or seizure that eventually causes bearing failure, usually abrupt in nature. The authors propose a method for thermal gradient removal with the use of current-controlled thermoelectric modules. To fulfill the task of control law adoption the numerical model of the heat distribution in a bearing has been built. Although sparse readings obtained experimentally with standard thermocouples are enough to determine thermal gradients successfully, validation of the bearing numerical model may be impeded. To improve spatial resolution of the experimental measurements the authors proposed a matrix of customized thermocouples located on the top foil. The foil acts as a shared conductor for each thermocouple that reduces the number of cable connections. The proof of concept of the control and measurement systems has been demonstrated in a still bearing heated by a cartridge heater.