共查询到18条相似文献,搜索用时 156 毫秒
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碰摩故障多自由度转子—轴承系统周期运动稳定性研究 总被引:4,自引:0,他引:4
以有限元理论为基础,建立考虑诸如非线性油膜力、陀螺效应等因素的碰摩故障转子—轴承系统多自由度模型,应用与Newmark法结合的打靶法分析碰摩故障多自由度转子—轴承系统的周期运动稳定性。研究系统随系统偏心距、碰摩间隙、碰摩摩擦因数、碰摩刚度等影响因素的失稳分岔规律。研究发现,小偏心距下系统发生hopf分岔失稳,而大偏心距下系统发生倍周期分岔失稳。减小系统的碰摩间隙、增大系统的摩擦因数或增大系统的碰摩刚度,将影响油膜涡动的形成,使系统失稳转速升高;对于轻度碰摩情况,系统分岔形式和失稳转速可能不发生改变,但对于重度碰摩情况,分岔形式和失稳转速将发生很大的变化。研究为相关转子—轴承系统故障诊断、振动控制及稳定性设计提供理论参考。 相似文献
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大间隙环流中轴承支承的单质量转子系统特征值分析 总被引:2,自引:0,他引:2
建立了大间隙环流中动压滑动轴承支承的单质量转子系统运动方程和特征方程,分析了系统参数对特征值的影响。结果表明,动压滑动轴承特性系数(如刚度和阻尼系数)、大间隙环流特性参数(如流体动力质量、壁面摩擦因数和无量纲间隙比)以及单质量转子系统参数(如系统固有频率)对系统特征值有不同程度的影响。结果表明:随着表征轴承刚度特性的ω1的增大,失稳转速增加,最终γ趋近于2,即相当于Jeffcott转子系统,同时临界转速也随之提高;随着表征轴承阻尼特性ζ的增大,失稳转速不变,临界转速提高;随着表征大间隙环流特性的流体动力质量α的增大,失稳转速不变,临界转速下降;随着表征大间隙环流特性的壁面摩擦因数和无量纲间隙比值β的增大,失稳转速和临界转速均不发生变化:随着表征单质量转子特性的固有频率ω0的增大.失稳转速下降.临界转速降低. 相似文献
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转子—轴承系统稳定性的试验研究 总被引:4,自引:0,他引:4
通过试验,研究了受瞬时扰动的转子—滑动轴承系统的运动稳定性问题。结果表明,在接近失稳转速的某个范围,甚至是较大的范围内,一定强度的外界瞬时扰动会导致系统油漠失稳。失稳后系统并未发散而常常是稳定在一极限环上作“半频涡动”。此半频涡动的振幅一般大于由转子不平衡量引起的同频涡动的振幅,而频率约定为系统当时转动频率的一半,并非系统不受扰失稳的界限值,即所谓“失稳转速”的相应频率值。 相似文献
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在非线性油膜力作用下 ,建立了转子 -联轴器系统的运动微分方程。非线性油膜力则采用有限差分法求解 ,对联轴器耦合的刚性转子系统和柔性转子系统分别进行了计算和分析。结果表明对于平衡转子系统在平衡点失稳后 ,在一个较大的转速范围内存在着稳定的涡动轨迹 ,联轴器两侧转子的质量相差越大 ,则发生 Hopf分岔所对应的转速越高。对于不平衡转子系统 ,在同步涡动轨道失稳后 ,系统将产生准周期和倍周期等一系列的分岔现象 ,并且质量偏心的位置对系统的动力学行为有影响。 相似文献
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裂纹和油膜耦合故障转子周期运动分岔分析 总被引:2,自引:1,他引:2
利用求解非线性非自治系统周期解的延拓打靶算法,研究了裂纹和油膜涡动耦合故障转子周期运动的分岔及失稳方式.研究发现,在偏心量一转速参数域内,耦合故障转子与油膜涡动转子的同频周期运动分岔失稳规律基本相同,在较大和较小的偏心量作用下,转子同频周期运动以倍周期分岔形式失稳,在适中的偏心量下,同频周期运动经Hopf分岔形式失稳.在裂纹深度-转速参数域内,耦合故障转子同频周期运动和倍周期运动的分岔失稳规律基本相同,随着裂纹深度加大,失稳转速降低,稳定性变差,但幅度并不明显. 相似文献
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大间隙环流中刚支转子系统振动特性研究 总被引:3,自引:0,他引:3
基于Myklestad传递矩阵法.建立了大间隙环流中转子系统的运动方程,采用数值方法分析转子系统的振动特性。数值计算结果表明,由于大间隙环流的流固耦合作用,使转子系统的固有频率、阻尼临界转速、稳定性和不平衡响应均发生了不同程度的变化。数值计算结果与已有的解析分析和实验结果有较好的一致性。 相似文献
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给出一种分析有限长大间隙环流中偏心转子动特性系数的简化数值分析方法。该方法基于有限长大间隙环流中同心转子的动特性系数计算了三维有限长大间隙环流中偏心转子的动特性系数。数值计算结果表明该方法行之有效。与已有的环压密封的其它数值计算结果和实验结果比较,该方法简单且具有较好的精度。 相似文献
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根据转子动力学和流体力学理论,建立了水平井钻柱涡动的动力学方程,分析了钻柱自重、井壁摩阻、钻井液流速等因素对水平井钻柱涡动的影响规律,阐释了诱发水平钻柱涡动产生的机理及边界条件。基于自主研制的水平井钻柱动力学试验装置,采用数值模拟和试验研究相结合的方法,分析了钻压、转速、流体速度等参数对钻柱涡动轨迹和涡动速度的影响规律。研究结果表明:在钻柱的远钻头段不会发生涡动,但是转速达到阈值后,近钻头段便会出现涡动现象,并且随着钻压和转速的增加,其涡动轨迹幅值也在增大;而近钻头段的涡动方向并不是始终如一的,存在正反两个方向的涡动,并且随着转速的增大,还会出现“半频涡动”现象;另外,钻井液的存在及其流动速度的增大都不会改变钻柱现有的运动状态,仅小幅增加其运动范围。研究成果对水平井钻井工艺参数的选定有一定的借鉴作用。 相似文献
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基于Myklestad传递矩阵法建立了大间隙环流中动压滑动轴承-转子系统的运动方程,用迭代方法确定了轴承.转子系统的静态平衡工作点,采用数值方法分析轴承-转子系统的振动特性。数值计算结果表明:大间隙环流使轴承-转子系统的固有频率、阻尼临界转速和稳定性均发生了不同程度的变化。大间隙环流不仅与轴承.转子系统发生了动态固耦合,而且也发生了静态固耦合。 相似文献
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Yeon-Sun Choi 《Journal of Mechanical Science and Technology》1994,8(4):404-413
Rubbing phenomena in rotor dynamics are investigated by theoretical and experimental approaches. Generating conditions of forward whirling, backward rolling, backward slipping, and partial rubbing are established for system parameters and rotor speeds. Possible whirling motions of the rotor in annular clearance are calculated for full annular rub under the conditions of positive normal force and geometric constraints. The theoretical calculations show that greater clearance results in greater runout and normal force, and the whirling responses are characterized by which natural frequency of the rotor or the stator is greater than the other. Receptances of the rotor and stator are used to explain the possibility of slipping for backward slipping and forward whirling, respectively. Effect of rotor eccentricity is also considered to find the maximum rotor speed for backward slipping during increasing rotor speed and the occurrence of forward whirl. Experiments are performed for two cases. The experimental results show good agreements with the theoretical predictions. 相似文献
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Dazhuan Wu Xinkuo Jiang Shiyang Li Leqin Wang 《Journal of Mechanical Science and Technology》2016,30(8):3477-3486
Currently, the dynamic characteristics of annular seals are numerically investigated mainly by solving the bulk flow equations using perturbation method, or by simulating the perturbed flow field of annular seal using CFD method. The adopted disturbance way is generally the circular whirling motion of rotor around seal centre with constant speed. Relative to the transient CFD simulation, the quasisteady CFD simulation introducing Moving reference frame (MRF) has been widely used by researchers. Both the dynamic mesh problem and the time-consuming problem suppress the use of transient CFD simulation in annular seal research. In the paper, a new transient CFD method based on rotor’s variable-speed whirl is presented to improve the time-consuming problem and all the (total 20) dynamic coefficients of concentric liquid seal can be obtained by only two transient CFD simulations, one for the variable-speed cylindrical whirl and the other for the variable-speed conical whirl. The results are compared with those from the experiment, the quasi-steady CFD method and the traditional transient CFD method based on constant-speed whirl. The comparisons show that the new transient method can keep the good accuracy of traditional transient method and meantime largely save the computational time. 相似文献
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The flow field inside a whirling annular seal has been measured using a 3-D Laser Doppler Anemometer (LDA) system. The seal investigated has a clearance of 1.27 mm, a length of 37.3 mm and is mounted on a drive shaft with a 50 percent eccentricity ratio. This results in the rotor whirling at the same speed as the shaft rotation (whirl ratio = 1.0). The seal is operated at a Reynolds number of 12000 and a Taylor number of 6300 (3600 rpm). The 3-D LDA system is equipped with a rotary encoding system which is used to produce phase averaged measurements of the entire mean velocity vector field and Reynolds stress tensor field from 0.13 mm upstream to 0.13 mm downstream of the seal. The mean velocity field reveals a highly three-dimensional flow field with large radial velocities near the inlet of the seal as well as a recirculation zone on the rotor surface. The location of maximum mean axial velocity migrates from the pressure side of the rotor at the inlet to the stiction side at the exit. Turbulence production is a maximum near the seal inlet as indicated by the rapid increase of the turbulence kinetic energy (κ). However, turbulence production and dissipation attain equilibrium fairly quickly with K remaining relatively constant over the last half of the seal. 相似文献
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Experimental studies on the effects of bearing supply gas pressure on the response of a permanent magnet disk-type motor rotor 总被引:1,自引:0,他引:1
Dongjiang Han Changliang Tang Long Hao Jinfu Yang 《Journal of Mechanical Science and Technology》2016,30(11):4887-4892
Vibrations, particularly low-frequency vibrations caused by self-excited gas films, significantly affect the safety and economy of turbomachinery, which becomes dangerous at high rotational speeds. This experimental study focuses on the dynamic characteristics of a Permanent magnet (PM) disk-type motor rotor supported by gas aerostatic bearings. Nonlinear dynamic behavior, including double low frequency and gas film half whirling, was analyzed in the experiments. The dynamic features of double low frequency and gas whirling are described in the paper. The most important finding is that the sum of the whirling ratios of low frequencies 1 and 2 is always 1.00. The occurrence mechanism requires further study. The effects of bearing supply gas pressure on the dynamic response characteristics of the multi-disk PM rotor are implemented to improve rotor stability. 相似文献