국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Brush Seals for Cryogenic Applications Performance, Stage Effects, and Preliminary Wear Results in LN2 and LH2
저자	Margaret P. Proctor, James F. Walker, H. Douglas Perkins, Joan F. Hoopes,
Keyword	Brush seals; Cryogenic seals; Shaft seals; Dynamic seals; Liquid hydrogen;
URL	http://gltrs.grc.nasa.gov/reports/1996/TP-3536.pdf
보고서번호	NASA TP-3536
발행년도	1996
출처	NASA Glenn Research Center
ABSTRACT	Brush seals are compliant contacting seals and have significantly lower leakage than labyrinth seals in gas turbine applications. Their long life and low leakage make them candidates for use in rocket engine turbopumps. Brush seals, 50.8쟭m (2in.) in diameter with a nominal 127-탆 (0.005-in.) radial interference, were tested in liquid nitrogen (LN2) and liquid hydrogen (LH2) at shaft speeds up to 35?00 and 65?00쟲pm, respectively, and at pressure drops up to 1.21 MPa (175 psid) per brush. A labyrinth seal was also tested in liquid nitrogen to provide a baseline. The LN2 leakage rate of a single brush seal with an initial radial shaft interference of 127졄m (0.005쟧n.) measured one-half to one-third the leakage rate of a 12-tooth labyrinth seal with a radial clearance of 127졄m (0.005쟧n.). Two brushes spaced 7.21졄m (0.248쟧n.) apart leaked about one-half as much as a single brush, and two brushes tightly packed together leaked about three-fourths as much as a single brush. The maximum measured groove depth on the Inconel 718 rotor with a surface finish of 0.81탆 (32졄in.) was 25졄m (0.0010in.) after 4.3쟦r of shaft rotation in liquid nitrogen. The Haynes-25 bristles wore approximately 25 to 76졄m (0.001 to 0.003쟧n.) under the same conditions. Wear results in liquid hydrogen were significantly different. In liquid hydrogen the rotor did not wear, but the bristle material transferred onto the rotor and the initial 127탆 (0.005in.) radial interference was consumed. Relatively high leakage rates were measured in liquid hydrogen. More testing is required to verify the leakage performance, to validate and calibrate analysis techniques, and to determine the wear mechanisms. Performance, staging effects, and preliminary wear results are presented.