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상부패드의 형상 변경을 통한 'Anti-fluttering 틸팅패드 저널베어링' 개발
양승헌,나운학,박희주,김재실,Yang, Seong Heon,Nah, Un Hak,Park, Heui Joo,Kim, Chaesil 한국유체기계학회 2005 한국유체기계학회 논문집 Vol.8 No.5
The tilting pad journal bearings have been widely used to support high pressure/high rotating turbine rotors owing to their inherent dynamic stability characteristics. However, fatigue damages in the upper unloaded pads and the break of locking pins etc. by pad fluttering are continuously taken place in the actual steam turbines. The purpose of this paper is to develop a new bearing model that can prevent bearing problems effectively by pad fluttering in a tilting pad journal bearing. A new bearing model which has a wedged groove is suggested from the studies of fluttering mechanism performed by previously research works. The fluttering characteristics of the upper unloaded pad are studied experimentally in order to verify the reliability of a new bearing model. It can be known that the phenomenon of pad fluttering nearly does not occurred in the new bearing model under the various experimental conditions. And it is observed that any kinds of bearing failures by pad fluttering does not detect in the application of acture steam turbines.
김영춘(Yeong Chun Kim),조석인(Seok In Cho),조양욱(Yang Uk Cho),박희주(Heui Joo Park) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.5
In the gas turbine, the clearance between the blade tip of the rotor and the inside of the stationary casing varies depending on the rotation of the rotor and the heat output of the combustor. Accordingly, the assembly clearance is determined, and the leakage of the gas occurs because of the gap during operation, affecting the efficiency of the system. Thus, designers use a variety of techniques to optimize this clearance, a typical method that reduces the relative variation of the clearance using heating and cooling mechanisms. In this study, we developed a method to control the blade tip clearance through the axial movement of the inclined blade without using heating and cooling mechanisms. Recently, we designed an advanced blade tip clearance control system that can control multi-step, not on-off control, to apply to large gas turbines developed by Doosan. The designed system is hydraulic and can be used with a maximum thrust of 100 tons, and the desired displacement can be moved in multiple stages as required. We have completed the reliability verification of the entire lifecycle level and applied it to the newly developed gas turbine.