INFLUENCES ON COUPLED LATERAL AND TORSION VIBRATION BEHAVIOR OF RUB-IMPACT ROTOR BY ROTOR-TO-STATOR CLEARANCE

With the establishment of the nonlinear coupled lateral and torsion vibrationequations of rub-impact Jeffcott rotor and through numerical simulations, the influences on lateraland torsion vibration behavior by rotor-to-stator clearance are analyzed, which prove that there isstrong impact on coupled lateral and torsion vibration behavior. Smaller the clearance is, morecomplex the motion of rotor is. When the clearance is larger, the frequency spectrum of rub-impactrotor is mainly composed of 1/2X, 1/3X and 1/4X components. With the decrease of clearance,quasi-periodic and chaotic motions will be present. Under different clearances, the bifurcationdiagrams of lateral and torsion vibrations can be divided into rub-free zone, rub-light zone andthree complex motion zones in which the motion trend of lateral vibration is similar to that of thetorsion vibration. Compared with the lateral vibration, the torsion vibration is of more motionforms and more abundant frequency components in amplitude spectrum.

Visual study on the characteristics of liquid and droplet in a novel rotor-stator reactor

Rotor–stator reactor(RSR), an efficient mass transfer enhancer, has been applied in many fields. However,the hydrodynamic characteristics of liquid flow in RSR are still a mystery despite they are fundamental for the mass transfer performance and processing capacity. In view of the above, this paper studies the liquid–liquid flow and liquid holdup in RSR under various conditions with a high-speed camera. The paper firstly demonstrates two flow patterns and liquid holdup patterns that we obtained from our experiment and then presents in succession a flow pattern and a liquid holdup criterion for the transition of film flow to filament flow and complete filling to incomplete filling. It is found that experimental parameters, including rotor–stator distance, rotational speed and volume flow rate exert great influence on the average droplet diameter and size distribution. Besides, by comparison and contrast, we also find that the experimental values match well with our previous predicted calculations of the average diameter, and the relation between the average diameter and the mean energy dissipation rate.

Parameter Modeling and Kinematical Simulation for Rotor and Stator of Screw Pump

The research object used in the dissertation was screw pump, which was widely applied in engineering field. The analysis of end face profile formation was completed on its main working components, i.e., rotor and stator. With the purpose of finding optimal parameters to improve the efficiency of screw pump design, the key technologies involved in the parametric modeling of rotor and stator were analyzed. The three-dimensional (3D) design software SolidWorks was used for the secondary development and parametric modeling of rotor and stator. After that the simulation models of different kinds of screw pumps were established based on the cycloid type, variation coefficient, and screw head number. Finally the COSMOSMotion was used to analyze the motion characteristics on the equidistant line of rotor, including velocity and acceleration. This design and modeling method has been used in screw pump enterprises for design and development, laying the foundation for finite element analysis and further optimization of screw pump.

MATCH-MODE METHOD AND ITS NUMERICAL SIMULATION FOR ROTOR-STATOR INTERACTION SOURCE MODES AND PROPAGATION MODES IN AN ANNULAR DUCT WITH MULTI-TREATMENTS

The suppressing design of the engine nacelle in an aircraft can benefit from the development of the prediction system for the sound fields in engine ducts which includes the prediction of the source generation and that of sound propagation in ducts. First, the acoustic match mode principle between the source modes of rotor stator interaction noise and the propagation modes is presented in this paper. Second, by utilizing this principle, the theoretical prediction method for rotor stator interaction noise generation and its propagation and attenuation in an annular duct with multi treatments is developed. That means that the prediction of sound propagation and attenuation in the segmented ducts might no longer completely depend on the in duct mode measurements, and the investigation on the sound propagation and attenuation in ducts can be accomplished not only by acoustic mode measurement, but also by making use of the source prediction to determine the source modes excited by rotor stator interaction. The effects of fan speed, blade/vane numbers, axial spacing between rotor and stator on the in duct sound attenuation and generated sound power level before and after ducts (also including the sound power level of blade passing frequency and its harmonics at the inlet of ducts) have been numerically calculated by using this prediction method. The reliability of this prediction method is verified by reasonable agreement between the predicted results with measured results in references. By analyzing the results of calculating cases, some reference criteria are provided for the engineering design of the suppressing engine nacelle.

GENERATOR VIBRATION FAULT DIAGNOSIS METHOD BASED ON ROTOR VIBRATION AND STATOR WINDING PARALLEL BRANCHES CIRCULATING CURRENT CHARACTERISTICS

Rotor vibration characteristics are first analyzed, which are that the rotor vibration of fundamental frequency will increase due to rotor winding inter-turn short circuit fault, air-gap dynamic eccentricity fault, or imbalance fault, and the vibration of the second frequency will increase when the air-gap static eccentricity fault occurs. Next, the characteristics of the stator winding parallel branches circulating current are analyzed, which are that the second harmonics circulating current will increase when the rotor winding inter-turn short circuit fault occurs, and the fundamental circulating current will increase when the air-gap eccentricity fault occurs, neither being strongly affected by the imbalance fault. Considering the differences of the rotor vibration and circulating current characteristics caused by different rotor faults, a method of generator vibration fault diagnosis, based on rotor vibration and circulating current characteristics, is developed. Finally, the rotor vibration and circulating current of a type SDF-9 generator is measured in the laboratory to verify the theoretical analysis presented above.

For Propulsion Applications It Is Possible to Utilize Both the Torque Output of the Rotor and the Reactional Torque Acting on the Stator of the Driving Electric Motor by Linearizing the Stator

This paper presents a novel idea of utilizing the reactional torque of the conventional electric motor as a linear output for propulsion in addition to the conventional torque output of the rotor. The idea is demonstrated by a theoretical proposal of linearizing the stator of one of the most used motors in Electrical Vehicles and Hybrid Vehicles. The proposed Linear Stator Motor is a simple modification without involving any functional change of the conventional motor. Though theoretical, the indicated possible input energy saving of more than 75% as compared to the conventional motor is no surprise, as by linearizing the stator, an almost equal linear propulsion output is added to the conventional rotor output. In addition to this remarkable saving in input energy, the proposed Linear Stator Motor that suits all types of vehicles, can maintain propulsion without the need for a mechanical transmission system. Also, in the case of watercraft and aircraft vehicles, no external mechanical propulsion drive system is required. It is just an internal force that can push the vehicle forward, backward, or laterally, while the conventional rotor output can be utilized for energy recovery by driving a DC generator.

Dynamical Analysis of Rub-impact Rotor System with Asymmetric Oil Film Force

Considering the effect of non-symmetry film force, nonlinear stiffness and nonlinear friction force, a dynamical model of rub-impact rotor system is established, then the nonlinear dynamical behavior is studied by numerical analysis method. The effect of rotation speed, nonlinear stiffitess ratio and speed effect factor on brifurcation and chaotic behavior for rub-impact rotor system is comprehensively analyzed. The analysis results show that the effect of non-symmetry film force, nonlinear stiffness and nonlinear friction force on the dynamical behavior of the rotor system has close relation with rotation speed. The chaotic behavior exists in a wider parameter region, and the chaotic evolution rule is more complicated. The research provides a reliable theory basis and reference for diagnosing some faults of the rotor system.

Creation and Development of Turbo-generators with Water-Cooled Stator and Rotor Windings in Shanghai Electrical Machinery Mfg Works

1. An Overview of Manufacture and Operation A turbine generator utilizing a new technology of electrical machinery industry, i.e. the windings of its stator and rotor all being inner water-cooled, was first successfully created in China and was known afterwards as a turbine generator with watercooled stator and rotor windings (Abbrev, TGWSR). The teachers from Zhejiang University came to Shanghai between

无刷双馈电机研究综述与展望

无刷双馈电机具有结构可靠、变频器容量小等优势,非常适合灵活运行于防爆、易燃等特殊或极端工况,近年来受到广泛关注。该文根据无刷双馈电机的基本工作原理,明确了该类电机的命名原则与规范名称;总结了现有定转子方案的结构及性能特点,综合考虑性能指标与结构工艺,提出了转子双套绕组的发展方向;梳理了无刷双馈电机的稳态等效电路模型及基于各类数学模型的优化设计方法,针对现存难以完整考虑不同转速工况性能的不足,阐明了利用新型同步-异步相串联等效电路进行优化设计的思路;对比分析了经典及新近出现的无刷双馈电机控制系统拓扑和控制策略特点,面向典型电动、发电工况建立了完整的电机及控制系统。最后,对无刷双馈电机的上述理论研究问题及工业应用的发展方向进行了总结阐述,为该类电机的深入研究及加快推广应用提供参考和指导。

Flow Field Improvement by Bowed Stator Stages in a Compressor with Different Axial Gaps Under Near Stall Condition

The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.

新型双定子无刷双馈风力发电机直接功率控制

新型双定子无刷双馈发电机包括内外功率绕组和内外控制绕组,二者分别通过中间带隔磁环的背靠背笼障转子进行磁场耦合。针对该新型双定子无刷双馈风力发电机提出一种直接功率控制方法,内外功率绕组及内外控制绕组分别串联以保持各自同相绕组的电磁一致性,将功率绕组有功和无功功率滞环比较器输出值及控制绕组磁链扇区号综合,采用查找表得到控制绕组机侧变流器所需输出的电压空间矢量。通过定量对比研究12/8极50 kW样机控制系统阶跃信号作用下的特性仿真与实验结果,验证了所提双定子无刷双馈风力发电机直接功率控制在亚同步~超同步速度变化范围内变速恒频发电、最大功率跟踪、无功功率与单位功率因数控制等方面的正确性、可行性和有效性。

汽轮发电机转子匝间短路对定子热响应特性的影响

本文分析了汽轮发电机转子匝间短路故障前后定子热响应特性,不仅考虑转子匝间短路引起电压下降对发电机强励动作的影响,还研究了热分布不平衡而引起的定子力学响应。首先推导了正常情况和转子匝间短路故障后加强励磁电流下的气隙磁通密度,得到了铁心损耗和绕组铜耗的解析表达式;然后建立了发电机故障前后的三维有限元仿真模型,对不同短路程度故障下的铁心损耗、绕组铜耗与定子温度进行了求解计算;最后实测了CS-5型故障模拟发电机在正常运行和不同短路程度故障下的定子温度,实验结果与理论分析、有限元仿真结果基本一致。结果表明,转子匝间短路故障后由于励磁电流的增强,发电机铁心损耗和绕组铜耗均会增加,定子温度明显上升,并且随着短路程度的增加而加剧;定子端面边缘位置的变形和应力幅值最大并且为热响应下的危险位置。

考虑表面粗糙度影响的低温涡轮泵特性与动静间隙流动分析

为分析低温涡轮泵过流部件表面粗糙度对其性能特性的影响,阐明表面粗糙度对涡轮泵动静间隙流场的影响机制,选择增材制造闭式叶轮涡轮氧泵为研究对象,在考虑低温介质热力学效应影响的前提下,采用液氮作为增压输送介质,对涡轮泵低温性能开展实验测试和数值计算。研究结果表明:在13 500~26 000 r/min转速范围内,相较于光滑壁面,考虑过流部件表面粗糙度后,采用液氮作为模拟介质得到的涡轮氧泵数值计算结果与实验测试数据吻合较好;随着离心叶轮及蜗壳等主流表面粗糙度从光滑壁面增加至36μm,涡轮氧泵扬程及效率分别下降了9.1%、10.6%;随着动静间隙过流部件表面粗糙度从0增加至20μm,涡轮泵叶轮轴向力合力系数显著降低了25.8%。研究结果对后续深入揭示表面粗糙度对低温涡轮泵动静间隙流场特性影响规律以及过流部件表面质量分区控制具有重要借鉴意义及参考价值。

基于Doehlert Matrix的全贯流泵装置定转子进出流间隙优化设计

全贯流泵是一种新型的机电-水泵一体式贯流泵,然而其在运行时存在定转子间隙回流,扰乱了叶轮内的流场分布,导致泵装置产生能量损失、压力波动和噪声等问题,影响泵站的正常运行。通过数值模拟和模型试验研究全贯流泵装置定转子间隙流的水力特性,结合Doehlert Matrix设计-响应面优化法对其定转子进、出流间隙结构进行优化设计,揭示全贯流泵装置定转子进、出流间隙结构对泵装置性能的影响机理,并得到最终优化的折角式定转子进、出流间隙结构方案为:外侧延伸段长度t1为4.921r,外侧收缩段长度x1为0.624r,内侧延伸段长度t2为3.655r,内侧收缩段长度x2为1.6r(r为定转子间隙宽度),使得全贯流泵装置扬程和效率分别提升约10.3%和5.2%。

燃气轮机透平转静盘腔内流动与传热研究进展

转静系盘腔是燃气轮机二次空气系统中的重要组成部分,盘腔内流动和传热特性对整机安全稳定运行十分重要。随着燃气透平进口温度的不断提升,对透平冷却设计的要求不断提高,透平盘腔流动换热特性研究也越来越受关注。研究人员从流动与换热两个方面对转静系盘腔进行实验测量和数值模拟研究,形成相对比较成熟的研究体系。总结近年来燃气透平转静盘腔流动传热及冷却的相关研究进展,根据结构的不同分别对中心进气和预旋进气转静系盘腔及转静系盘腔的轮缘密封进行介绍,分析3种不同盘腔结构内部流动型态,介绍了预旋系统结构和轮缘密封结构对盘腔内流动传热特性影响的相关实验与数值研究现状。最后,基于当前研究热点和发展趋势,总结并展望了转静系盘腔未来研究的发展方向。

一种定子单绕组无轴承开关磁阻电机的转子位移控制方法

提出了一种用于定子单绕组无轴承开关磁阻电机(Bearingless switched reluctance motor,BLSRM)的转子位移控制方法。首先介绍了定子单绕组无轴承开关磁阻电机的基本结构和工作原理,基于等效磁路法建立悬浮力和刚度的数学模型。其次,建立了转子动力学模型以获取悬浮力与转子位移间的关系模型。最后,设计了一台实验样机并在电机上进行悬浮控制实验。实验结果验证了所提控制方法的有效性。

新型双转子双定子永磁同步发电机的磁场及耦合效应分析

为了解决目前海上风力发电机存在的成本高、体积大等问题,提出一种新型双转子双定子永磁同步发电机(DRDS-PMSG).建立了发电机的等效磁路模型,采用有限元分析方法评估了发电机的电磁特性及内外电机的耦合效应,部分仿真结果得到了实验验证.仿真结果表明:随着内、外永磁体相对位置的改变,电机等效磁路存在3种典型情况,并可通过耦合系数对耦合区域的等效磁阻进行描述;内、外电机的耦合效应体现在齿槽转矩、电磁转矩等电磁特性上,内、外电机的齿槽转矩峰峰值分别为0.52和1.64 kN·m,电磁转矩平均值分别为11.65和27.09 kN·m,转矩脉动分别为6.02%和4.12%;总体来看,内、外电机之间存在一定程度的耦合,但该耦合效应被隔磁环有效削弱.

抽水蓄能机组动静干涉与相位共振诱发振动故障机理及抑制方法研究

动静干涉与相位共振故障直接影响抽水蓄能电站水泵水轮机安全与稳定运行。本文以某水泵水轮机为对象,系统研究了由动静干涉产生的水力激振模式,并对其进行相位共振风险评估。通过实例计算分析了张河湾与黑麋峰抽水蓄能水泵水轮机由动静干涉引起厂房振动影响因素。同时,通过统计国内部分抽水蓄能电站水力参数,计算了动静干涉水力激振模式与相位共振风险系数RF,并提出相应预控措施。为其他大型抽水蓄能电站的振动问题提供参考,并为即将大规模建设的抽蓄电站安全稳定性提供积极借鉴意义。

基于定转子槽结构协同优化的交流牵引电机电磁降噪优化设计方法

针对交流牵引电机存在电磁噪声较大的问题,提出一种基于定转子槽结构协同优化的交流牵引电机电磁降噪优化设计方法。分析了交流牵引电机电磁噪声的产生机理,阐述了在电机定转子槽底部开槽降噪的基本原理与具体设计方法,并对开槽位置与槽口尺寸进行了参数优化研究。最后对降噪效果进行了仿真验证,同时与传统降噪方法进行了对比分析,结果表明采用所提电磁降噪优化设计方法对交流牵引电机定转子槽结构进行优化处理后,在保证其效率有所增加的情况下,电磁噪声得到了显著下降,因而取得了较好的降噪效果。

适用于DFIG连接到直流微网的双变换器设计与实现

针对双馈感应式发电机DFIG(doubly-fed induction generator)-DC连接系统电流谐波严重、双VSI连接系统损耗大等问题,设计了1种将三相DFIG连接到直流微电网的新型双变换器连接系统。首先,详细阐述了双变换器连接系统的拓扑结构、脉宽调制PWM(pulse-width modulation)测量和DFIG模型等工作原理。与传统连接系统不同,所提连接系统采用开放端绕组结构,在定子绕组的每一侧使用1个三桥臂整流器,这些桥臂通常由绝缘栅双极晶体管IGBT(insulated gate bipolar transistor)组成,为了减少控制开关的数量和降低成本,采用二极管替代了1个整流器中的IGBT;然后,给出了新型拓扑结构下SSC和RSC的控制策略;接着,与DFIG-DC连接系统和双VSI连接系统在电流谐波畸变、转矩脉动和半导体损耗等方面进行了仿真比较,说明所提方法优越性;最后,针对0.56 kW DFIG进行实验验证,结果表明了所提方法在损耗、谐波以及转矩脉动的优势。