Effect of bristle pack position on the rotordynamic characteristics of brush-labyrinth seals at various operating conditions

• Published in: Chinese journal of aeronautics Vol. 33; no. 4; pp. 1192 - 1205
• Main Authors: ZHANG, Yuanqiao, LI, Jun, LI, Zhigang, YAN, Xin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2020
• Subjects: Bristle pack position; Brush-labyrinth seal; Porous medium; Rotordynamic characteristics; Whirling rotor method; Brush-labyrinth seal; Bristle pack position; Rotordynamic characteristics; Whirling rotor method; Porous medium
• ISSN: 1000-9361
• DOI: 10.1016/j.cja.2019.12.005

Over the last few decades, the research on the effect of bristle pack position on the rotordynamic characteristics of the brush-labyrinth seals is not sufficient. To this end, two kinds of brush-labyrinth seals for the bristle pack element installed upstream of the labyrinth teeth named BSU and installed downstream of the labyrinth teeth called BSD were used to investigate the effect of bristle pack position on the rotordynamic characteristics of the brush-labyrinth seals. Using the numerical model combining the porous medium model and the whirling rotor method, the rotordynamic characteristics of the BSU and BSD at various operating conditions including four kinds of pressure ratios, five kinds of inlet preswirl speeds and four kinds of rotor spinning speeds were conducted. The obtained results show that the effects of operating conditions on rotordynamic coefficients for the different seal configurations are different. The direct stiffness, cross-coupled stiffness and direct damping of the BSU are lower than those of the BSD. The rotordynamic coefficients of the BSU are more insensitive to the operating conditions variation. From the perspective of the seal stability, the BSU is a better brush-labyrinth seal configuration at high pressure ratio, high positive preswirl or high rotor spinning speed conditions. While in the case of low pressure ratio, low positive preswirl or low rotor spinning speed conditions, the BSD is a better choice.