Dynamic similarity design of rotor system with squeeze film damper
-
摘要:
针对航空发动机中常见的带有挤压油膜阻尼器 (SFD)转子的动力学相似问题,建立了一种相似建模方法。从带有阻尼的转子的振动微分方程着手,通过方程分析法推导了转子振动过程中的不平衡力相似关系和阻尼力相似关系。以挤压油膜阻尼器的油膜力和油膜方程为基础建立了挤压油膜阻尼器参数与转子相似参数之间的数学关系,并给出了相应的工程设计方法。以某带有挤压油膜阻尼器的单转子系统为例,建立了带有挤压油膜阻尼器的相似转子系统,使用有限元法分析了该转子系统与其相似系统的动力学特性,分析结果显示:在仅考虑转子系统内挤压油膜阻尼器阻尼的情况下相似系统的不平衡响应与原转子系统不平衡响应误差低于1%。
-
关键词:
- 模态分析 /
- 转子动力学 /
- 挤压油膜阻尼器 (SFD) /
- 不平衡响应 /
- 动力学相似
Abstract:In order to research the dynamic similarity problems of rotors with squeeze film damper (SFD), which are common in aero-engines, a similar modeling method was established. Starting from the vibration differential equation of the rotor with damping, the similar relationship between the unbalanced force and the damping force in the rotor vibration process was derived by equation analysis method. Based on the oil film force and oil film equation of the squeeze film damper, the mathematical relationship between the parameters of the squeeze film damper and the similar parameters of the rotor was established, and the corresponding engineering design method was given. Taking a single-rotor system of the rotor as an example, a similar rotor system with a squeeze film damper was established. The dynamic characteristics of the rotor system and its similar systems were analyzed using the finite element method. The analysis results showed that the unbalance response error between the similar system and the original rotor system was lower than 1% when only considering the damping of squeeze film damper in the rotor system.
-
Key words:
- modal analysis /
- rotor dynamics /
- squeeze film damper (SFD) /
- unbalance response /
- dynamic similarity
-
表 1 相似关系表
Table 1. Similarity relationship list
参数名称 参数符号 相似关系 参数间的关系 系统1 系统2 材料弹性模量 $ E' $ $ E $ $E' = {\lambda _{{E} } }E$ 材料密度 $\,\rho '$ $\,\rho$ $\,\rho ' = {\lambda _{\rho } }\rho$ 径向尺寸 $ d' $ $ d $ $d' = {\lambda _{{d} } }d$ 振动幅值 $ Z' $ $ Z $ $Z' = {\lambda _{{Z} } }Z$ ${\lambda _{{d} } } = {\lambda _{{Z} } }$ 偏心量 $ \varepsilon ' $ $ \varepsilon $ $ \varepsilon'= {\lambda _{{\varepsilon }}}\varepsilon $ ${\lambda _{ {\varepsilon } } } = {\lambda _{{d} } } = {\lambda _{{Z} } }$ 长度 $ l' $ $ l $ $l' = {\lambda _{{l} } }l$ 轴向位置 $ x' $ $ x $ $x' = {\lambda _{{x} } }x$ ${\lambda _{{x} } } = {\lambda _{{l} } }$ 临界转速 $ \omega ' $ $ \omega $ $\omega ' = {\lambda _{\omega} }\omega$ 转子转速 $\varOmega '$ $\varOmega$ $\varOmega ' = {\lambda _{ {\varOmega } } }\varOmega$ ${\lambda _{ {\varOmega } } } = {\lambda _{\omega } }$ 时间 $ t' $ $ t $ $t' = {\lambda _{{t} } }t$ 质量 $ m' $ $ m $ $m' = {\lambda _{{m} } }m$ 单位长度质量 $ U' $ $ U $ $U' = {\lambda _{{U} } }U$ ${\lambda _{{U} } } = {\lambda _{{m} } }\lambda _{{x} }^{ {{ - 1} } } = {\lambda _{\rho } }\lambda _{{d} }^{{2} }$ 转动惯量 $ I' $ $ I $ $I' = {\lambda _{{I} } }I$ ${\lambda _{{I} } } = \lambda _{{d} }^{{4} }$ 表 2 挤压油膜阻尼器参数相似关系表
Table 2. Similarity relationship list of SFD parameters
参数名称 参数符号 相似关系 系统1 系统2 滑油黏度 $\,\mu '$ $\,\mu$ $\,\mu ' = {\lambda _{\mu} }\mu$ 油膜长度 ${L'_{\text{c} } }$ $ {L_{\text{c}}} $ ${L'_{\text{c} } } = {\lambda _{ { { {L} }_{\text{c} } } } }{L_{\text{c} } }$ 油膜半径 ${R'_{\text{c} } }$ $ {R_{\text{c}}} $ ${R'_{ {\text{c} } } } = {\lambda _{ { { {R} }_{\text{c} } } } }{R_{\text{c} } }$ 油膜间隙 ${C'_{\text{r} } }$ $ {C_{\text{r}}} $ ${C'_{\text{r} } } = {\lambda _{ { { {C} }_{\text{r} } } } }{C_{\text{r} } }$ 表 3 相似参数表
Table 3. Similarity parameters list
相似参数 相似比符号 相似比 弹性模量 ${\lambda _{{E} } }$ 1 密度 ${\lambda _{\rho } }$ 1 轴向尺寸 ${\lambda _{{l} } }$ 0.8 径向尺寸 ${\lambda _{{d} } }$ 0.8 偏心量 ${\lambda _{{\varepsilon }}}$ 0.8 转速 ${\lambda _{\omega}}$ 1.25 阻尼值 ${\lambda _{{c} } }$ 0.64 不平衡质量 ${\lambda _{\rm{ub}}}$ 0.4096 滑油黏度 ${\lambda _{\mu } }$ 1 油膜长度 ${\lambda _{ {{L_{\rm{c}}} } } }$ 0.7427 油膜半径 ${\lambda _{ { {{R} }_{\text{c} } } } }$ 0.8 表 4 转子系统主要参数
Table 4. Main parameters of rotor system
参数 系统1 系统2 主轴长度/m 0.644 0.805 支承跨距/m 0.5408 0.676 主轴半径/m 0.0264 0.033 盘1质量/kg 8.3507 16.31 盘2质量/kg 9.7024 18.95 盘1极转动惯量/(kg·m2) 0.0452 0.138 盘2极转动惯量/(kg·m2) 0.0609 0.186 1号支承刚度/109 (N/m) 0.8 1 表 5 挤压油膜阻尼器主要参数
Table 5. Main parameters of SFD
参数 系统1 系统2 2号支承刚度/106 (N/m) 2.6 3.2 油膜长度/m 0.0074 0.01 油膜半径/m 0.054 0.0675 油膜间隙/m 0.000128 0.00016 油膜间隙比/‰ 2.37 2.37 表 6 线性阻尼下的不平衡响应
Table 6. Unbalance response of the rotor with linear damping
参数 系统1 系统2 参数目标相似比 参数实际相似比 不平衡量/(g·cm) 6.144 15 0.410 0.410 线性阻尼值/(N·s/m) 640 1000 0.64 0.64 响应峰值转速/(r/min) 4221 3376 1.25 1.25 响应峰值/μm 70.94 88.58 0.80 0.80 表 7 挤压油膜阻尼器线性状态下的不平衡响应信息
Table 7. Unbalance response information under linear state of SFD
参数 系统1 系统2 参数目标相似比 参数实际相似比 不平衡量/(g·cm) 2.048 5 0.410 0.410 响应峰值转速/(r/min) 4238 3390 1.25 1.25 响应峰值/μm 21.49 26.78 0.800 0.802 偏心比峰值 0.1679 0.1674 1.000 1.003 无量纲阻尼系数 1.639 1.639 1.00 1.00 表 8 挤压油膜阻尼器双稳态信息
Table 8. SFD bi-stable information
参数 系统1 系统2 参数目标相似比 参数实际相似比 最低转速/(r/min) 4736 3791 1.25 1.249 最高转速/(r/min) 4844 3877 1.25 1.249 最低转速最大偏心比 0.815 0.814 1 1.001 最高转速最大偏心比 0.823 0.821 1 1.002 最低转速最小偏心比 0.467 0.465 1 1.004 最高转速最小偏心比 0.607 0.602 1 1.008 响应峰值 105.2 μm 131.2 μm 0.8 0.802 -
[1] 廖明夫. 航空发动机转子动力学[M]. 西安: 西北工业大学出版社, 2015. [2] 刘展翅. 弹支挤压油膜阻尼器设计与特殊工况下阻尼器减振特性研究[D]. 西安: 西北工业大学, 2016.LIU Zhanchi. Study of the squeeze film dampers design and the vibration attenuating characteristics under special conditions[D]. Xi’an: Northwestern Polytechnical University, 2016. (in Chinese) [3] 牛继辉. “可容模态”下航空发动机转子动力学设计[D]. 西安: 西北工业大学, 2019.NIU Jihui. The dynamics design of aero-engine rotor based on “workable modal”[D]. Xi’an: Northwestern Polytechnical University, 2019. (in Chinese) [4] 袁文忠. 相似理论与静力学模型实验[M]. 成都: 西南交通大学出版社, 1998. [5] 王永亮,孙立权,崔颖,等. 考虑陀螺效应的转子动力学相似准则[J]. 航空动力学报,2015,30(12): 2840-2847. doi: 10.13224/j.cnki.jasp.2015.12.004WANG Yongliang,SUN Liquan,CUI Ying,et al. Dynamics similarity criteria of rotor dynamic with gyroscopic effect[J]. Journal of Aerospace Power,2015,30(12): 2840-2847. (in Chinese) doi: 10.13224/j.cnki.jasp.2015.12.004 [6] 罗忠,陈广凯,李建章,等. 考虑轴承刚度的转子系统动力学相似模型设计[J]. 东北大学学报(自然科学版),2015,36(3): 402-405. doi: 10.3969/j.issn.1005-3026.2015.03.022LUO Zhong,CHEN Guangkai,LI Jianzhang,et al. Design of dynamic similarity model of rotor system considering the bearing stiffness[J]. Journal of Northeastern University (Natural Science),2015,36(3): 402-405. (in Chinese) doi: 10.3969/j.issn.1005-3026.2015.03.022 [7] HARRIS C M,CREDE C E,TRENT H M. Shock and vibration handbook[J]. Physics Today,1962,15(9): 65-65. [8] WU J J. Prediction of lateral vibration characteristics of a full-size rotor-bearing system by using those of its scale models[J]. Finite Elements in Analysis and Design,2007,43(10): 803-816. doi: 10.1016/j.finel.2007.05.001 [9] 郭银朝,孟光. 考虑油膜惯性力时Jeffcott转子-挤压油膜阻尼器系统的突加不平衡响应特性[J]. 机械强度,1997,19(3): 1-5. doi: 10.3321/j.issn:1001-9669.1997.03.001GUO Yinchao,MENG Guang. Influence of fluid inertia forces on the sudden unbalance responses of jeffcott rotor-squeeze film damper system[J]. Journal of Mechanical Strength,1997,19(3): 1-5. (in Chinese) doi: 10.3321/j.issn:1001-9669.1997.03.001 [10] 孟光. 非线性柔性转子-同心型挤压油膜阻尼器系统稳态及双稳态响应的稳定性分析[J]. 航空学报,1990,11(7): 333-340. doi: 10.3321/j.issn:1000-6893.1990.07.005MENG Guang. Stability analysis on the steady state and bis-table responses of flexible rotor supported in squeeze film dampers[J]. Acta Aeronautica et Astronautica Sinica,1990,11(7): 333-340. (in Chinese) doi: 10.3321/j.issn:1000-6893.1990.07.005 [11] 刘方杰. 挤压油膜阻尼器失效分析方法[J]. 北京航空航天大学学报,1998,24(5): 533-537. doi: 10.3969/j.issn.1001-5965.1998.05.010LIU Fangjie. Methods of analysis failure of squeeze film damper[J]. Journal of Beijing University of Aeronautics and Astronautics,1998,24(5): 533-537. (in Chinese) doi: 10.3969/j.issn.1001-5965.1998.05.010 [12] 刘方杰,陈照波. 挤压油膜阻尼器失效问题的实验研究[J]. 强度与环境,1998(4): 17-23.LIU Fangjie,CHEN Zhaobo. Experimental research of failure of squeeze film damper[J]. Structure & Environment Engineering,1998(4): 17-23. (in Chinese) [13] 刘展翅,廖明夫,丛佩红,等. 航空发动机转子挤压油膜阻尼器设计方法[J]. 航空动力学报,2015,30(11): 2762-2770. doi: 10.13224/j.cnki.jasp.2015.11.026LIU Zhanchi,LIAO Mingfu,CONG Peihong,et al. Design method of squeeze film damper for aero-engine rotors[J]. Journal of Aerospace Power,2015,30(11): 2762-2770. (in Chinese) doi: 10.13224/j.cnki.jasp.2015.11.026 [14] 刘展翅,廖明夫,丛佩红,等. 静偏心对挤压油膜阻尼器减振特性影响实验研究[J]. 推进技术,2016,37(8): 1560-1568. doi: 10.13675/j.cnki.tjjs.2016.08.021LIU Zhanchi,LIAO Mingfu,CONG Peihong,et al. Experimental investigation for effects of static eccentricity on vibration attenuating characteristics of squeeze film damper[J]. Journal of Propulsion Technology,2016,37(8): 1560-1568. (in Chinese) doi: 10.13675/j.cnki.tjjs.2016.08.021 [15] LIU Z, LIAO M F. Scale model design of a turboshaft engine with mid turbine frame[R]. Brussels, Belgium: the 10th International Conference on Mechanical and Aerospace Engineering (ICMAE), 2019. [16] NELSON H D,MCVAUGH J M. The dynamics of rotor-bearing systems using finite elements[J]. Transactions of the American Society Mechanical Engineers Journal of Engineering for Industry,1976,98(2): 593-600. [17] YAMAMOTO T, ISHI D Y. Linear and nonlinear rotor dynamics: a modern treatment with applications, second edition[M]. Weinheim, Germany: Wiley-VCH Verlag GmbH and Company KGaA, 2012. [18] 闻邦椿, 顾家柳, 夏松波, 等. 高等转子动力学[M]. 北京: 机械工业出版社, 2000. [19] 《航空发动机设计手册》总编委会. 航空发动机设计手册: 第19册 转子动力学级整机振动[M]. 北京: 航空工业出版社, 2000.