裂纹-碰摩耦合故障转子系统时频特性分析

分析了无故障转子系统、裂纹故障转子系统、裂纹-碰摩故障转子系统的起机过程时域特性，并结合小波等高图分析其时域、频域特性。理论结果显示，裂纹-碰摩故障转子系统既保留了裂纹故障的高频分量特征，又保留了碰摩故障的低频成分特征，升速时域曲线出现波动。通过实验验证了理论结果。研究表明，通过启机过程的时域波形结合小波等高图，可以诊断转子系统的裂纹-碰摩耦合故障。     

非线性油膜力作用下的碰摩转子系统动力学分析

目的:在讨论转子系统碰摩问题时,必须要考虑非线性碰摩力的影响,通过建立合理的模型来进行碰摩转子系统动力学分析十分重要。方法:运用基于Hertz接触理论的非线性碰摩力模型建模并进行数值仿真计算,对不同碰摩刚度下的故障转子系统动力学响应进行了研究。结果:通过分析发现,在碰摩刚度较大时,与线性刚度碰摩模型相比,采用Hertz接触理论碰摩力模型仿真出的结果非线性特性更强,系统碰摩特征更加明显,有利于判断碰摩故障的发生;结论:结合相关实验结果,验证了Hertz碰摩模型的正确性及将其运用在碰摩故障转子系统建模中的可行性。     

双盘悬臂转子轴承系统碰摩故障数值仿真与实验分析

分别建立了双盘悬臂转子轴承系统的力学模型、数学模型和碰摩力模型，同时利用转子碰摩故障的实验装置，研究了转子系统碰摩故障的非线性振动特性，对中间盘碰摩时转子系统的动力学特性、悬臂盘发生碰摩时转子系统的动力学特性进行了进一步分析，数值仿真结果与实验结果一致，对实际工程中转子系统的安全稳定运行具有一定的实际参考价值。     

非线性裂纹转子系统碰摩故障参变特性研究

早期裂纹转子系统中,裂纹故障不易检测到,并可能会进一步引发碰摩故障。文中针对这种耦合故障情形,分析系统的动力特性以及裂纹参数、碰摩参数和轴承参数变化对系统特性的影响。结果表明,裂纹转子系统发生碰摩故障时,两种非线性因素相互影响且不是线性叠加,使系统变得更加复杂。同时三个参数对系统特性有明显不同的影响,尤其是裂纹参数和碰摩参数的变化,系统特性发生较大的变化。因此,工程实际裂纹转子系统的故障监测与诊断过程中,应该充分考虑裂纹故障和碰摩故障之间的相互影响,建立合理的分析模型的基础上,注重监测裂纹参数和碰摩参数变化带来的影响。     

齿轮耦合的故障转子系统弯扭耦合振动特性研究

利用有限元方法研究了齿轮耦合汽轮机组转子系统健康时与发生裂纹故障、碰摩故障时的系统弯扭耦合振动特性。根据转子系统各阶临界转速的变化情况,并结合动态响应图,分析研究了转子系统发生裂纹、碰摩故障时的一些非线性动态特性。通过对转子系统弯扭耦合振动特性的研究,为设计工作提供参考。     

EMD方法在转子局部碰摩故障诊断中的应用

针对转子系统局部碰摩故障振动信号的特征，将经验模态分解方法（Empirical Mode Decomposition，简称EMD）应用于转子局部碰摩故障诊断中。采用EMD方法对转子振动信号进行分解，实现碰摩、背景和噪声信号分离，从而提取转子系统局部碰摩振动信号的故障特征。试验分析结果表明，对具有局部碰摩故障的转子振动信号进行EMD分解得到的基本模式分量（IMF）具有明显的调幅特性，而其他状态下的转子振动信号经过EMD分解后得到的IMF分量没有明显的调幅特性。因此，EMD方法可以有效地应用于转子系统局部碰摩故障诊断中。     

双转子-支承-机匣耦合系统碰摩振动响应分析及试验验证

以某型航空发动机双转子试验器为研究对象,采用Newmark-β数值积分方法求解系统的动力学响应,在考虑高低压转子中介轴承的耦合和机匣的弹性变形及其运动的基础上,建立了碰摩故障双转子-支承-机匣耦合系统动力学模型,理论分析了转速、转子偏心量和碰摩刚度对转子系统动力学特性的影响并进行了相关试验。研究结果表明：发生碰摩故障时,转子和机匣测点频谱分析图中会出现转子的倍频和组合频率,可将其作为判断系统发生局部碰摩的特征信号;随着转子偏心量和碰摩刚度的增大,碰摩幅值响应愈加明显,碰摩程度亦愈加严重;机匣测点振动量值存在衰减,后续理论建模过程中应考虑传递过程的衰减。本研究结论可为碰摩故障机理的探究和碰摩故障的诊断提供参考。     

转子--机壳碰摩故障研究

使用基于Henz接触理论的非线性碰摩模型，对工程中的多盘转子系统碰摩故障现象进行了研究。研究成果有助于更好地把握多盘碰摩转子的振动特征，可以为更准确地诊断转子碰摩故障和改善转子系统的动力学特性提供理论依据。     

双盘悬臂转子轴承系统松动碰摩耦合故障分析

针对考虑松动-碰摩耦合故障的双盘悬臂立式转子-轴承系统，建立了该系统的力学模型和有限元模型，并基于非线性有限元方法和接触理论研究了松动刚度和碰摩间隙两个重要参数对系统动力学特性的影响。通过对在不同松动刚度和不同碰摩间隙时系统动力学特性的研究分析，发现转静件碰摩能够减小松动引起的低频振动，支座松动产生的碰摩具有明显的方向性，从而得出转子系统中诊断松动-碰摩耦合故障的依据。     

基于谐波分量的转子系统碰摩故障定量诊断方法

提出一种利用碰摩转子系统响应中的高次谐波分量进行碰摩位置和碰摩力定量诊断的新方法。基于谐波平衡理论分析碰摩故障转子系统的动力学特性,证明了碰摩故障转子系统中任意两节点之间高次谐波分量之比等于无故障转子系统频率响应矩阵的相关元素之比。根据此关系,提出转子系统碰摩故障模型诊断方法和步骤:利用正常转子系统与故障转子系统响应的任意一阶谐波分量之差,结合转子系统的动力学模型,就可以诊断出碰摩的位置;进而可以根据故障转子系统响应的各次谐波分量还原出碰摩力分量。为验证该方法的有效性,对一转子系统进行偏碰和整周碰摩时的数值仿真,并分析支撑刚度及噪声对诊断方法的影响;又在模型转子试验台上进行了试验。该方法仅利用一个转速下两个节点的振动响应即可实现碰摩故障的在线定量诊断,因此便于在实际旋转机械上实行。     

Modified breathing mechanism model and phase waterfall plot diagnostic method for cracked rotors

Transverse breathing cracks are a primary damage mode in rotor systems and seriously influence the safety and reliability of equipment operation. The vibration characteristics exhibited by cracked rotors when passing through critical speeds serve as important evidence in the diagnosis of cracks, and a breathing mechanism model without weight dominance is needed to study these resonant characteristics. In this work, a restoring force modified model is proposed for studying the breathing mechanism of cracked Jeffcott rotors without weight dominance. Furthermore, a novel phase waterfall plot method that can identify frequency components with weak amplitudes is proposed to analyze the vibration response characteristics of cracked Jeffcott rotors. Numerical and experimental studies indicate that the phase waterfall plots effectively recognize the weak characteristic frequencies of cracked rotors. This study can also provide references for the crack monitoring of rotor systems.     

汽轮机转子高速动平衡试验中制动时间的分析计算

随着变频技术的不断发展,变频器回馈制动方式被越来越广泛地应用于汽轮机转子高速动平衡试验系统中的转子制动。文中简要介绍了回馈制动的特点,对汽轮机转子高速动平衡试验时转子的制动时间进行分析和计算,为制动方案的选择提供参考。     

高速柔性转子的主要零部件对其动力特性的影响分析

用SAMCEF／ROTOR分析软件建立某新型涡轴发动机动力涡轮空心轴组件和转子（装实心或空心传动轴）动力特性计算的有限元分析模型,基于动力特性（临界转速、振型和不平衡响应）计算结果,分析传动轴、测扭转准轴和动力涡轮盘对转子动力特性的影响,为改进设计提供理论依据。     

基于离散像素法的双螺杆压缩机螺杆转子间隙布置方法

为了保证双螺杆压缩机转子在工作运行时的平稳性,提出了一种基于离散像素法的啮合间隙布置方法,根据像素筛选原则及间隙判定原则,结合齿轮啮合及磨损原理, 基于双螺杆压缩机转子的齿廓型线特征以及转子在加工工况下的热膨胀仿真结果,对双螺杆压缩机阴阳转子的齿间间隙布置方法进行了研究,利用所提方法可在一对无啮合间隙的阴阳转子的端面型线上合理布置齿间间隙,调整转子啮合位置,减小双螺杆压缩机运行过程中的振动和磨损,降低运行功耗。     

Combined effects of channel curvature and rotor configuration on the performance of two-stage viscous micropumps

The combined effects of channel curvature and rotor configuration on the performance of two-stage viscous micropumps were studied numerically. The Navier-Stokes equations were simulated to investigate the performance of two-stage micropumps. The performance of two-stage micropumps was studied in terms of the dimensionless mass flow rate and dimensionless driving power. Four different rotor configurations were designed by changing placement of two rotors inside a microchannel: Two aligned and two staggered configurations. The aligned rotor configuration of type 1 is to place the two rotors along the convex wall, while type 2 is to place them along the concave wall. Numerical results show that the rotor configuration plays a significant role in the performance of two-stage micropumps. The channel curvature acts in a different way according to the rotor configuration. The mass flow rate of aligned rotor configuration of type 1 is greatly improved by the channel curvature, while it diminishes the mass flow rate of type 2. The maximum mass flow rate for the aligned rotor configuration of type 1 is obtained when the two rotors are placed at the junction of the circular and straight sections of the channel. The performance of staggered configurations is negligibly affected by the channel curvature. This characteristics is found due to rotation direction of the rotors. As the two rotors rotate in the opposite direction for the staggered configurations, the flow characteristics in the circular section is little affected by the channel curvature. The circumferential distance between the two rotors can be optimized in terms of the mass flow rate. The optimal value of the circumferential distance is about L = 1.4 for the staggered rotor configurations, and it is almost independent of the channel curvature. As the channel height increases, the circumferential distance becomes less significant for the staggered rotor configurations while it becomes significant for the aligned rotor configurations.

     

双螺杆转子结构特性流固耦合数值模拟

以双螺杆转子为研究对象,依据流固耦合理论,通过求解捏合机内部流体和双螺杆转子固体耦合方程,研究不同工况下的流体压力和扭矩对双螺杆转子应力和变形的影响规律。分析计算结果表明:螺杆转子的变形和应力主要是不同工况下的扭矩、流体压力载荷及耦合场作用引起的;螺杆间隙对捏合机的生产效率和质量有很大影响,阴阳螺杆转子最大变形量是设计最佳螺杆间隙的关键因素;一定功率下,转子的最大变形量和最大应力值分别与转子扭矩、流体压力的大小正相关;一定转速下,转子的最大变形量和最大应力值与捏合机功率正相关。研究结果为新型双螺杆捏合机的合理设计与性能预测提供了理论依据。     

Exploiting the orbital motion of water particles for energy extraction from waves

In wave motion, the water particles are known to follow orbital paths. This orbital motion was used to drive five-bladed Savonius rotors. Experiments were performed on an array of four rotors placed in a two-dimensional (2-D) wave channel. The flow around the rotors was documented using particle image velocimetry measurements. The submergence of the rotors and the distance between them were varied, and the rotational speeds of the rotors (N_n) were recorded at different wave frequencies. It was found that rotational speeds increased with an increase in the wave frequency, as it amplified the wave height that increased the kinetic energy of the particles in their orbital motion. The rotational speeds decreased when the distance between the rotors increased. High rotational speeds are recorded when the array of the rotors is placed close to the water surface at the smallest centre-to-centre distance between the rotors.     

燃气轮机拉杆转子畸变相似问题研究

针对燃气轮机拉杆转子结构复杂,其试验模型相对于原型存在较大程度的畸变,无法直接反映原型真实动力学特性的问题,采用量纲分析法研究了燃气轮机拉杆转子的相似问题,得出了拉杆转子模型发生畸变的判据,提出了一种转子畸变模型的补偿方法,并得到了相应的畸变补偿量,推导了畸变补偿模型与原型的动力学特性畸变相似准则,实现了通过畸变补偿模型直接获得原型动力学特性的目的。算例分析验证了理论分析的正确性。     

Study on precision grinding of screw rotors using CBN wheel

With increasing demands for high-speed and high-precision machining technology, CBN shape grinding is an effective means in the field of precision machining for screw rotors. Aiming at the high precision machining of screw rotors, a mathematical model for the axial profiles of the CBN wheel for machining screw rotors is developed based on theory of gear engagement. Small electroplated CBN wheel is firstly used to grinding screw rotors. Taking the backlash of screw rotors and the coating thickness of CBN layer into consideration, the modification of the base body of the wheel shape is introduced into the design of CBN wheel. For reducing the tooth profile errors of screw rotors induced by mounting errors and wears of CBN wheel, a mathematical model of the error analyses is established and the influence curves of the profile errors affected by mounting errors and radius error of grinding wheel are proposed. The electroplated CBN wheels for the screw rotors are made to verify the validity and effectiveness of the presented method and the machining experiments were performed. Results of this study reveals that the method proposed in this paper can be used as the precision grinding of screw rotors.     

双转子平动式啮合电动机设计与转矩分析

提出一种新型的四相双转子平动式啮合电动机,该电动机的每个磁极由一个定子和内、外转子构成.4个磁极的内转子固连在一起构成一个4极内平动转子,外转子固连在一起构成一个4极外平动转子.控制磁极的工作顺序,可以驱动内、外平动转子在4个偏心轴约束下作方向相反且同步的公转运动,并带动两个内齿圈与外齿轮啮合输出低速大扭矩运动,该结构相互抵消了惯性力,增大了输出转矩.设计制作物理样机,运用有限元法分析在不同转子位置角的磁链特性.依据磁共能原理,计算电动机的静态转矩.通过样机试验获得电动机的转速、转矩特性.与传统的电动机和减速器组成的驱动装置相比较,双转子平动式啮合电动机具有起动快、效率高、输出转矩大的特点,是一种可行的平动电动机结构.