Dynamic response of hydro-turbine set shaft system under stochastic hydraulic excitation
BAI Bing1, ZHANG Lixiang2
1. School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450011, China; 2.Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
Abstract:The forces acting on a hydro-turbine generator set shaft system were analyzed, including the nonlinear oil film force in the guide bearings, mechanical unbalanced forces on the rotor and runner, the unbalanced magnetic force on the rotor, and the hydraulic imbalance force on the runner. Then a nonlinear dynamic model for the shaft system was established, and the stochastic hydraulic excitation in the model was simulated with a zero mean, identically independent distributed(i.i.d.)signal, and its magnitude was changed by adjusting the random variance. The responses of the key parts(rotor, runner and guide bearings)to the changes in rotational speed, eccentric mass and exciting current, namely amplitude-time history curves, trajectory, amplitude spectra and Poincare diagram and bifurcation patterns, were obtained by solving the dynamic model equations. Results showed that the rotational speed and eccentric mass have a considerable influence on the vibration response of main parts in the shaft system. And the lateral throws at the turbine guide bearing and runner become obviously bifurcated as the stochastic hydraulic excitation increases. The excitation has strong influence on the vibration mode and stability of the shaft system.
白冰, 张立翔. 随机水力激励下机组轴系的动力响应[J]. 排灌机械工程学报, 2017, 35(5): 398-403.
BAI Bing, ZHANG Lixiang. Dynamic response of hydro-turbine set shaft system under stochastic hydraulic excitation. Journal of Drainage and Irrigation Machinery Engin, 2017, 35(5): 398-403.
[1]刘保国,张信志.水轮发电机组主轴系统非线性动力学问题的计算分析[J].中国机械工程,2001,12(8): 939-942. LIU Baoguo, ZHANG Xinzhi. Study on computer simulation technique of nonlinear dynamic problem for shaft of hydro-generator unit[J]. China mechanical engineering, 2001,12(8):939-942.(in Chinese)[2]李兆军,杨旭娟,蔡敢为,等.水轮发电机组主轴系统的水流激励特性[J].排灌机械工程学报,2011,29(5):423-426,431. LI Zhaojun, YANG Xujuan, CAI Ganwei, et al. Hydraulic excitation exerting on main shaft system of hydraulic turbine-generator units[J]. Journal of drainage and irragation mechinery engineering, 2011,29(5):423-426,431.(in Chinese)[3]马震岳,董毓新.水轮发电机组动力学[M].大连:大连理工大学出版社,2003.[4]WANG Liguo, ZHANG Xiangjun, XU Dianguo, et al. Study of differential control method for solving chaotic solutions of nonlinear dynamic system[J]. Nonlinear dynamics, 2012,67(4):2821-2833.[5]张立,罗兴锜,郭鹏程.大型水轮发电机组轴系非线性瞬态响应分析[J].水力发电,2006,32(5): 48-51. ZHANG Li, LUO Xingqi, GUO Pengcheng. Dynamics analysis of non-linear transient response for large hydraulic generator unit[J]. Water power, 2006,32(5):48-51.(in Chinese)[6]ZHANG Leike, MA Zhenyue, SONG Bingwei. Dynamic characteristics of a rub-impact rotor-bearing system for hydraulic generating set under unbalanced magnetic pull[J]. Archive of applied mechanics, 2013,83(6):817-830.[7]郭丹,何永勇,褚福磊.不平衡磁拉力及对偏心转子系统振动的影响[J].工程力学,2003,20(2):116-121. GUO Dan, HE Yongyong, CHU Fulei. The calculation of unbalanced magnetic pull and its effect on vibration of an eccentric rotor[J]. Engineering mechanics, 2003,20(2):116-121.(in Chinese)[8]张雷克,马震岳,宋兵伟.水轮发电机组在不平衡磁拉力及密封力下振动特性分析[J].水电能源科学,2010,28(9): 117-120. ZHANG Leike, MA Zhenyue, SONG Bingwei. Characteristics analysis of hydroelectric generating set under unbalanced magnetic puul and sealing force of runner[J]. Water resources and power, 2010, 28(9): 117-120.(in Chinese)[9]张雷克,马震岳.不平衡磁拉力作用下水轮发电机组转子系统碰摩动力学分析[J].振动与冲击,2013,32(8): 48-54,67. ZHANG Leike, MA Zhenyue. Dynamic analysis for rotor system with rub-impact of a hydraulic generating set under unbalanced magnetic pull[J]. Journal of vibration and shock, 2013,32(8):48-54,67.(in Chinese)[10]白晖宇,荆建平,孟光.电机不平衡磁拉力研究现状与展望[J].噪声与振动控制,2009,29(6):5-7,33. BAI Huiyu, JING Jianping, MENG Guang. Survey and outlook on the research of the unbalanced magnetic pull in the motors[J]. Noise and vibration control, 2009,29(6):5-7,33.(in Chinese)[11]DONÁT Martin. Computational modelling of the unbalanced magnetic pull by finite element method[J]. Procedia engineering, 2012,48:83-89.[12]PENNACCHI Paolo, FROSINI Lucia. Computational model for calculating the dynamical behavior of generators caused by unbalanced magnetic pull and experimental validation[J].Journal of sound and vibration, 2008,312(1):332-353.[13]姚大坤,邹经湘,黄文虎,等.水轮发电机转子偏心引起的非线性电磁振动[J].应用力学学报,2006,23(3): 334-337. YAO Dakun, ZOU Jingxiang, HUANG Wenhu, et al. Nonlinear electromagnetic vibration by eccentricity of hydro-generator rotor[J]. Chinese journal of applied mechanics, 2006, 23(3): 334-337.(in Chinese)[14]宋志强,马震岳.考虑不平衡电磁拉力的偏心转子非线性振动分析[J].振动与冲击,2010,29(8): 169-173. SONG Zhiqiang, MA Zhenyue. Nonlinear vibration analysis of eccentric rotor with unbalanced electromagnetic pull[J]. Journal of vibration and shock, 2010, 29(8): 169-173.(in Chinese)[15]LYU Yanjun, ZHANG Yongfang, YU Yangbing, et al. Nonlinear dynamics of flexible rotor system supported on fixed-tilting pad combination journal bearing[J]. Journal of Central South University of Technology, 2011,18(3): 610-617.[16]ZHANG Yongfang, WU Peng, GUO Bo, et al. Approximate solution of oil film load-carrying capacity of turbulent journal bearing with couple stress flow[J]. Chinese journal of mechanical engineering, 2015,28(1):106-114.[17]ZHANG Wanfu, YANG Jiangang, CAO Hao, et al. Experimental identification of fluid-induced force in labyrinth seals[J]. Journal of mechanical science and technology, 2011,25(7):2485-2494.[18]LI Zhonggang, CHEN Yushu. Research on 1:2 subharmonic resonance and bifurcation of nonlinear rotor-seal system[J]. Applied mathematics and mechanics, 2012,33(4):499-510. [19]LI Xinyang, YANG Jiangang, XU Wanjun. Research and comparison on the leakage and fluid force between the axial and the radial labyrinth seal[J]. Journal of mechanical science and technology, 2015,29(11):4611-4620.[20]HUANG Zhiwei, ZHOU Jianzhong, YANG Mengqi, et al. Vibration characteristics of a htdraulic generator unit rotor system with parallel misalignment and rub-impact[J]. Archive of applied mechanics, 2011,81(7):829-838.[21]ZHANG Leike, MA Zhenyue, WU Qianqian, et al. Vibration analysis of coupled bending-torsional rotor-bearing system for hydraulic generating set with rub-impact under electromagnetic excitation[J]. Archive of applied mechanics, 2016,86(9):1665-1679.[22]CHANG-JIAN Cai-Wan, CHEN Cha’o-Kuang. Couple stress fluid improve rub-impact rotor-bearing system-nonlinear dynamic analysis[J].Applied mathematical modelling, 2010,34(7):1763-1778.[23]ADILETTA G, GUIDO A R, ROSSI C. Chaotic motions of a rigid rotor in short journal bearings[J]. Journal of nonlinear dynamics, 1996,10(3):251-269.[24]白冰,白新理,张立翔. 水轮发电机组轴系的非线性动力响应分析[J]. 云南水力发电,2017,33(1):151-154,161. BAI Bing, BAI Xinli, ZHANG Lixiang. The non-linear dynamic response analysis of the main shaft system of a turbo-generator unit[J]. Yunnan water power, 2017,33(1):151-154,161.(in Chinese)[25]HOLMES P, LUMLEY J L, BERKOOZ G, et al. Turbulence, Coherent Structures, Dynamical Systems and Symmetry[M]. New York, USA: Cambridge University Press, 1996.[26]白冰.水轮发电机组轴系辨识及振动研究[D].昆明:昆明理工大学,2015.