Kakuda Branch Office, National Aerospace Laboratory(NAL)
Kakuda Branch Office, National Aerospace Laboratory(NAL)
Space Technology Research Group, National Aerospace Laboratory(NAL)
Kakuda Branch Office, National Aerospace Laboratory(NAL)
Former Kakuda Branch Office, National Aerospace Laboratory(NAL)
出版者
航空宇宙技術研究所
出版者（英）
National Aerospace Laboratory(NAL)
雑誌名
航空宇宙技術研究所報告
雑誌名(英)
Technical Report of National Aerospace Laboratory TR-750
巻
750
ページ
64
発行年
1983-01
抄録（英）
This investigation was carried out in order to develop a high speed, face-contact bellows mechanical seal for a liquid hydrogen turbopump of a liquid oxygen(LOX) and liquid hydrogen(LH2) rocket engine. The present report describes the results of experimental and analytical studies on the static and dynamic sealing performance and the wear process of a newly developed mechanical seal for an LH2 turbopump. The main results obtained in this study are as follows: (1)The starting torque and static sealing performance were markedly affected by the change of the stationary seal face distortion, which was caused by fluid pressure and temperature, due to wear. The seal friction loss power fell by a small value after the mechanical seal faces had completely run-in. (2)The sealing balance ratio of the mechanical seal, which stabilized the dynamic sealing at high rotative speed, was above 0.77. This high value was due to the large amount of the opening force. (3)The high opening force ratio noted in the experiment was well explained by the leakage flow model, in which a liquid phase was assumed to be changed, due to viscous friction, to a gas phase in parallel seal clearance. The opening force ratio increased with the increase of rotative speed and decreased with the increase of the seal clearance. (4)The temperature at the rubbing surface of the chrominum plate was about 500C at the initial operating stage, according to the measurement of the chromium plate hardness. Recrystalization also occured in a part of the chromium plate. (5)Thermal cracks, which were formed on the chromium plate sealing surface of the rotating ring, were characteristic of crack edge lifting. The carbon seal face worn by the cracks made the proper seal clearance, which increased the opening force and drastically decreased the load on the rubbing seal surface. This process occured at the initial operating stage even for a long operation. (6)The thermal distortion of the carbon seal surface due to friction heat ocurred when the seal nose-piece temperature was above 60K. This dynamical thermal distortion was prevented by the selection of a sealing balance ratio below 0.82, which allowed the seal surfaces to wear evently. (7)The wear of the seal surfaces was efficiently decreased, even under severe operating conditions, when the proper seal clearance(0.5～0.8μm) was set before the operation.
液体水素用高速・接触式メカニカルシールの密封特性に関する研究
naltr00750.pdf
(12.54MB)
