基于螺杆转子啮合接触线加载气体轴向力的热应力分析

以往对螺杆转子进行应力分析时,转子上所受的载荷都是以集中应力的方式简化加载的,计算结果不能反映转子的真实受力以及变形情况。但是通过螺杆转子啮合接触线,在接触线接触区槽段按照实际情况加载螺杆转子气体轴向力,对螺杆转子进行热应力分析,真实准确解析出螺杆转子真实应力、变形以及约束反力,解决了长期以来对螺杆转子受力变形简化精度过低的问题,提高了计算精度,有较高的工程应用价值。     

新型对称式三螺杆压缩机的设计

传统的双螺杆压缩机只有一个吸气孔口和一个排气孔口,其螺杆转子在轴向和径向上都是单向受力,使螺杆转子受力不均.介绍了一种新型的对称式三螺杆压缩机的具体结构和结构优点,并对螺杆转子进行了受力分析.结果表明该新型对称式三螺杆压缩机的转子轴向受力平衡,且中间阳转子径向受力也平衡,主要零部件受力状况得到改善,噪声污染大大减弱,达到了降低成本、提高使用寿命的目的.     

螺杆转子断裂故障分析及修复方法

针对某公司螺杆压缩机转子出现断裂现象,结合转子受力及转子材质分析得到转子产生断裂的真正原因,并提出了转子断裂的修复方法,为螺杆压缩机转子故障分析提供了重要的指导依据.     

新型交叉轴双螺杆膨胀机转子的设计与受力性能研究

针对现有双螺杆膨胀机螺杆转子在工作过程中承受的轴向力较大的问题,提出采用交叉轴锥形螺杆转子结构,减小螺杆转子轴向力;建立了交叉轴锥形螺杆转子三维模型;使用双螺杆膨胀机的工作过程模型,确定了工作情况下螺杆转子所受的温度和压力载荷;使用ANSYS软件对螺杆转子在温度和压力作用下的变形和轴向力进行了分析。结果显示,交叉轴锥形螺杆结构对减小双螺杆膨胀机转子轴向力有较好的效果。     

螺杆压缩机转子齿形的优化

综述了螺杆压缩机转子齿形的研究与发展状况,分析了对转子齿形的基本要求,给出了设计合形的一般步骤和方法。并利用螺杆压缩机计算机辅助设计系统,定量计算了三种不同告形的几何特性值、热力性能和动力特性。还针对小型空调用螺杆制冷压缩机的具体应用场合,对转子齿形进行了优化。     

转子上作用力的计算（二）

用虚功原理对螺杆压缩机进行动力分析,转子型面轴向力的计算归结为基元容积投影的静矩计算,使复杂的空间问题转化为简单的平面问题.     

部分负荷工况下双螺杆制冷压缩机转子轴向受力试验研究

为了提高双螺杆压缩机运行的可靠性,对部分负荷工况下转子轴向受力进行了试验研究,测量了部分负荷下压缩机转子齿槽内气体压力的变化趋势以及转子轴向受力的变化特性,并根据转子轴向受力组成,分别得到了气体轴向力和端面轴向力对转子轴向受力的影响.研究结果表明:随着负荷降低,由于转子工作过程压缩段长度的减小,转子轴向受力呈现出不断减...     

螺杆压缩机3-5齿转子扭转角的计算

螺杆转子,必须通过一定的科学方法,计算、选择出正确的扭转角。但目前为止,少有文献对转子扭转角的计算提出具体的方法。首先介绍了螺杆压缩机转子扭转角的计算原理。而后,详细描述了螺杆压缩机吸气流量的具体计算方法,以及3-5齿型转子对所对应的轴向吸气口的设计原理及方法、步骤,提供了最终的,符合实际要求的轴向吸气口形状和轴向吸气口面积数值的获取方法。最后,以有限迭代法,详细讨论和推导出了转子扭转角的计算、选择方法和具体操作步骤。     

基于积累弦长三次样条函数的螺杆齿槽容积计算

针对螺杆压缩机转子型线优化设计及压缩机工作过程仿真的需要，采用积累弦长三次样条函数的型线设计方法，分别建立了阴阳转子型线的参数化方程，并在此基础上建立了螺杆齿槽容积的计算模型，通过一个具体的算例，对齿槽容积随转角变化进行了计算。     

摆动转子压缩机受力分析与理论计算

在较大压差工况下,摆动转子压缩机比滚动活塞压缩机有更明显的优势。但由于其独特的结构,导致部件受力复杂,使实际设计计算缺乏理论依据。为此,本文对各部件受力进行了理论分析和数值计算。结果表明:气体力是影响大多数力变化的主要因素,部分运动部件之间存在较大的作用力;排气阀开启时刻,各作用力达到最大值;除气体力形成的负载力矩外,摆动转子与偏心轮之间的力矩是压缩机内的第二大负载力矩。     

基于动力学有限元模型的多跨转子轴系无试重整机动平衡研究*

针对多跨转子轴系现场动平衡需频繁启停机的问题,结合影响系数平衡法和模态振型平衡法特点,提出一种新的基于动力学有限元模型的轴系无试重整机动平衡法。综合转子动力学相关理论和有限元技术,通过仿真构建与轴系结构尺寸和运行参数相符的转子动力学有限元模型。采用柔性转子共振分离原理,分析轴系振型和不平衡振动阶次以确定各跨转子加重平衡平面数和位置,分别在各跨转子平衡位置处施加不平衡激励,获取轴系平衡转速下各振动测点处不平衡响应,计算出相应的加重影响系数,从而取代轴系现场动平衡中需要多次启停机试重测取过程。然后采用最小二乘法通过解平衡矢量方程组得到轴系所需的平衡配重。最后以模拟百万兆瓦超超临界汽轮机的四跨五支承柔性转子轴系试验台为例,应用该方法开展了2 700 r/min转速下轴系四个平面同时配重动平衡试验,单点降幅最高达53%,实现了无试重下柔性转子轴系整机动平衡,可有效减少因盲目试重次数,节省平衡费用和周期。     

Second Generation Wavelet Finite Element and Rotor Cracks Quantitative Identification Method

The presence of cracks in the rotor is one of the most dangerous and critical defects for rotating machinery. Defect of fatigue cracks may lead to long out-of-service periods, heavy damages of machines and severe economic consequences. With the method of finite element, vibration behavior of cracked rotors and crack detection was received considerable attention in the academic and engineering field. Various researchers studied the response of a cracked rotor and most of them are focused on the crack detection based on vibration behavior of cracked rotors. But it is often difficult to identify the crack parameters quantitatively. Second generation wavelets (SGW) finite element has good ability in modal analysis for singularity problems like a cracked rotor. Based on the fact that the feature of SGW could be designed depending on applications, a multiresolution finite element method is presented. The new model of SGW beam element is constructed. The first three natural frequencies of the rotor with different crack location and size were solved with SGW beam elements, and the database for crack diagnosis is obtained. The first three metrical natural frequencies are employed as inputs of the database and the intersection of the three frequencies contour lines predicted the normalized crack location and size. With the Bently RK4 rotor test rig, rotors with different crack location and size are tested and diagnosed. The experimental results denote the cracks quantitative identification method has higher identification precision. With SGW finite element method, a novel method is presented that has higher precision and faster computing speed to identify the crack location and size.     

Model-based identification of two cracks in a rotor system

The dynamics and diagnostics of cracked rotor have been gaining importance in recent years. Relatively few authors have addressed the problem of multi crack assessment for rotors. In the present study a model-based method is proposed for the on-line identification of two cracks in a rotor. The fault-induced change of the rotor system is taken into account by equivalent loads in the mathematical model. The equivalent loads are virtual forces and moments acting on the linear undamaged system to generate a dynamic behaviour identical to the measured one of the damaged system. The rotor has been modelled using finite element method, while the cracks are considered through local flexibility changes. The cracks have been identified for their depths and locations on the shaft. The nature and symptoms of the fault, that is crack, are ascertained using the FFT.     

Lateral Vibration Analysis of Flexible Shafts Supported on Elliptical Journal Bearings

This paper presents the development of a finite element procedure for the dynamic analysis of flexible rotors supported on fluid-film elliptical journal bearings operating under several operating conditions. The rotating shaft is modeled by using Timoshenko beam theory and the coupled rotating components, such as disks and impellers, are modeled by using lumped masses. The modeling of the elliptical journal bearings is performed by solving the lubrication equations generated from the application of a linearized perturbation method on the classical Reynolds equation. The bearing carrying-load capacity and the linearized dynamic force coefficients can be predicted for elliptical bearings with different preloads and journal eccentricities. The rotor transient whirling unbalance response is estimated by performing the time integration of the finite element equations using Newmark method. Experimental whirling unbalance response of a rotating shaft supported at two identical journal bearings is used to validate the finite element procedure. A comparative analysis of the dynamic response of flexible rotors supported on both cylindrical and elliptical journal bearings is performed to show that some elliptical bearings are capable of attenuating the rotor unbalance response more efficiently than cylindrical bearings are.     

The significance of axial stresses and out-of-plane restraints on the design of rotors

The importance of axial stresses in rotors and the effect of out-of-plane restraints at the hub, on the in-plane stresses are investigated by using the finite element technique, with a hexahedral isoparametric element. The stresses in a non-dimensional form are compared with the plane stress solution. The probable mode of deformation of rotors of various axial thicknesses is given. The use of the above method in the analysis of an asymmetric rotor is also demonstrated.     

一种轴型盘转子系统临界转速的计算分析

考虑轴段转动惯量及剪切变形效应的影响,建立了以轴段矩阵代替转盘矩阵的新的传递矩阵法,并编写了相应的用户子程序;对含轴型盘转子系统的临界转速及振型进行比较深入的计算分析,并通过同常规传递矩阵法、Riccati传递矩阵法,以及有限元方法所得系统前3阶临界转速结果进行比较,探讨了转盘厚度与传递矩阵的选取之间的关系。计算结果表明:对于轴型盘转子系统,采用新的传递矩阵法所得的临界转速更接近有限元计算结果。当悬臂盘厚度达到轴长的0.1或居中盘厚度超过跨度比例0.08时,应采用新的传递矩阵法。     

螺杆压缩机转子受力计算

螺杆转子旋转时，基元容积的密封线，只用轴向平移，而不改变其形状。因此可利用这一特性，将密封线投影到相关平面来进行转子受力分析。用微元齿间容积的轴向、径向、切向气体分力．沿整个转子长度方向积分，即可得到作用在转子上的力，同时解出轴承支反力。     

卧螺离心机转子动力特性计算

利用大型通用有限元分析软件Ansys计算了卧螺双转子结构的临界转速.在计算过程中,用Matrix27用户自定义单元模拟连接内外转子的滚动轴承,建立了双转子结构的有限元耦合模型.并对计算结果与测试结果进行了比较,两者符合的比较好.     

基于接触有限元的齿轮-转子系统动态特性分析

考虑齿轮-转子系统各部件的弹性,基于接触有限元理论提出一种能够高保真模拟齿轮副连续啮合过程的动态特性分析方法。该方法利用实体有限元进行系统建模,可体现各部件的结构特征;基于接触有限元进行啮合过程仿真,可模拟系统的时变刚度、啮合冲击等真实激励进而得到全面准确的响应信息。以一直齿轮-转子系统为例进行啮合过程的数值仿真,利用中心差分法求得系统各动力学参量在时域上的响应,通过中心距偏差、动态传递误差、动态接触力等参数分析系统的弯曲振动、扭转振动、齿轮副的啮合特性及其耦合关系。研究结果表明：考虑各部件尤其是转子的弹性后,系统的非线性振动特性显著,齿轮副啮合存在明显的双边冲击及脱啮现象。     

Sensitive parameters’ optimization of the permanent magnet supporting mechanism

The fast development of the ultra-high speed vertical rotor promotes the study and exploration for the supporting mechanism. It has become the focus of research that how to improve the speed and overcome the vibration when the rotors pass through the low-order critical frequencies. This paper introduces a kind of permanent magnet (PM) supporting mechanism and describes an optimization method of its sensitive parameters, which can make the vertical rotor system reach 80000 r/min smoothly. Firstly we find the sensitive parameters through analyzing the rotor’s features in the process of achieving high-speed, then, study these sensitive parameters and summarize the regularities with the method of combining the experiment and the finite element method (FEM), at last, achieve the optimization method of these parameters. That will not only get a stable effect of raising speed and shorten the debugging time greatly, but also promote the extensive application of the PM supporting mechanism in the ultra-high speed vertical rotors.