Fluid-induced vibration characteristics of anti-stagnant labyrinth seals
WANG Jiarong1,ZHANG Wanfu1,2,JIANG Guangzheng3,YANG Xingchen1,LI Chun1,2
1.School of Energy and Power Engineering , University of Shanghai for Science and Technology, Shanghai 200093, China;
2.Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;
3.Xi’an Thermal Power Research Institute Co., Ltd., Xi’an 710054, China
Annular seals are the key component of turbomachines to reduce the fluid leakage.The fluid-induced vibration characteristics of the annular seal are extremely crucial to the system stability.Based on the computational fluid dynamics method and a multiple frequencies whirling model, the fluid-induced vibration characteristics of an anti-stagnant labyrinth seal were investigated.The effect of anti-stagnant nozzles’geometry parameters and its position on the dynamic and static characteristics was studied.The fluid-induced vibration suppression mechanism of the anti-stagnant nozzles was examined.The results show that the anti-stagnant flow can significantly suppress the circumferential flow, and improve the pressure distribution on seal cavities and the system stability.Compared with the traditional labyrinth seal, the anti-stagnant labyrinth seal possesses a smaller cross-coupled stiffness coefficient k, a larger direct damping coefficient C and an effective damping coefficient Ceff.The suppression effect on the unstable vibration is especially remarkable at low frequencies.There exists an optimal radial position for the anti-stagnant nozzle with identical geometric parameters.When the centroid height hc is 1.65 mm, the effective damping Ceff is the largest.Increasing the nozzle inlet height hin and decreasing the ratio of outlet/inlet height hout/hin can both improve the system stability.The anti-stagnant labyrinth seal with hin=1.00 mm, hout/hin=0.25, hc=1.65 mm, is the optimal structure for the current calculation conditions, while the leakage flowrate increases slightly.
[2]曹树谦, 陈予恕.现代密封转子动力学研究综述[J].工程力学,2009,26(增刊2): 68-79.
CAO Shuqian, CHEN Yushu.A review of modern rotor/seal dynamics[J].Engineering Mechanics, 2009,26(Suppl.2): 68-79.
[3]ZHANG W F, YAO Z, YANG J G, et al.Influence of tilting rotor on characteristics of fluid-induced vibration for labyrinth seals[J].Journal of Vibroengineering, 2016,18(8): 5416-5431.
[4]ROSENBERG S S, ORLIK W G, MARCENKO U A.Investigating aerodynamic transverse forces in labyrinth seals in cases involving rotor eccentricity[J].Translated from Energomasinostroenie, 1974,8: 15-17.
[5]何立东, 夏松波.转子密封系统流体激振及其减振技术研究简评[J].振动工程学报, 1999,12(1): 66-74.
HE Lidong, XIA Songbo.Review on aerodynamic excitation and its elimination method in the rotor-seal system[J].Journal of Vibration Engineering, 1999,12(1): 66-74.
[6]BENCKERT H, WACHTER J.Flow induced spring coefficients of labyrinth seal for applications in rotordynamics[C]//Proceedings of the Rotordynamic Instability Problems in High-Performance Turbomachinery Workshop.College Station: Texas A & M University, 1980.
[7]CHILDS D W, MCLEAN J E, ZHANG M, et al.Rotordynamic performance of a negative-swirl brake for a tooth-on-stator labyrinth seal[J].Journal of Engineering for Gas Turbines and Power, 2015,138(6): 62505.
[8]SUN D, WANG S, FEI C W, et al.Numerical and experimental investigation on the effect of swirl brakes on the labyrinth seals[J].Journal of Engineering for Gas Turbines and Power, 2016,138(3): 32507.
[9]BALDASSARRE L, BERNOCCHI A, FONTANA M, et al.Design and assessment of its stabilizing effect on compressor rotordynamic performance[C]//Proceedings of the 43rd Turbomachinery Symposium.College Station: Texas A & M University, 2014.
[10]ALEXANDRINA U, HANXIANG J, GEN F, et al.The effects of fluid preswirl and swirl brakes design on the performance of labyrinth seals[J].Journal of Engineering for Gas Turbines and Power, 2018,140(8): 82503.
[11]MEMMOTT E A.Stability of centrifugal compressors by applications of tilt pad seals, damper bearings and shunt holes[C]//Institution of Mechanical Engineers Conference Publications.[S.l.]: Medical Engineering Publications Ltd., 1992.
[12]SOTO A, ELIAS A, CHILDS D W.Experimental rotordynamic coefficient results for: (a) a labyrinth seal with and without shunt injection and (b) a honeycomb seal[C]//ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition.[S.l.]: ASME, 1998.
[13]KIM C H, LEE Y B.Test results for rotordynamic coefficients of anti-swirl self-injection seals[J].Journal of Tribology, 1994,116(3): 508.
[14]KIM N, PARK S, RHODE D L.Predicted effects of shunt injection on the rotordynamics of gas labyrinth seals[C]//ASME Turbo Expo 2001: Power for Land, Sea, and Air.[S.l.]: ASME, 2001.
[15]ZHANG W F, GU Q L, WANG T X.Study on the rotordynamic performance of a novel anti-stagnation labyrinth seal[J].Journal of Vibration Engineering & Technologies, 2020,8(6): 835-846.
[16]LI Z, LI J, YAN X.Multiple frequencies elliptical whirling orbit model and transient RANS solution approach to rotordynamic coefficients of annual gas seals prediction[J].Journal of Vibration & Acoustics, 2013,135(3): 31005.
[17]IWATSUBO T, ISHIMARU H.Consideration of whirl frequency ratio and effective damping coefficient of seal[J].Journal of System Design and Dynamics, 2010,4(1): 177-188.