International Journal of Rotating Machinery最新文献_第5页

Research on Meshing Stiffness and Vibration Response of Pitting Fault Gears with Different Degrees 不同程度点蚀故障齿轮啮合刚度及振动响应研究

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-02-01 DOI: 10.1155/2020/4176430

Jie Liu, Chengye Wang, Wenchao Wu

In order to study the influence of pitting on meshing stiffness, the normal distribution function is used to simulate the pitting location of pitting gear, and the potential energy method is used to analyze the influence of pitting on meshing stiffness. At the same time, the meshing stiffness of pitting gears with different degrees is analyzed by finite element method, and the validity of the calculation results with potential energy method is verified. On the basis of meshing stiffness, the dynamic model of gear system is established, and the vibration response of pitting gear system with different degrees is analyzed. The results show that with the increase of pitting area, the meshing stiffness decreases; the closer the meshing area of the driving wheel is to the pitting line, the more the meshing stiffness decreases, resulting in the intensification of vibration response and periodic impact; and in the time history diagram, there is a small spurious frequencies near the meshing frequency; in the phase diagrams and the Poincare diagram, trajectory and discrete point aggregation area is gradually increased.

为了研究点蚀对啮合刚度的影响，采用正态分布函数模拟点蚀齿轮的点蚀位置，并采用势能法分析点蚀对啮合刚度的影响。同时，采用有限元法对不同程度点蚀齿轮的啮合刚度进行了分析，验证了势能法计算结果的有效性。在啮合刚度的基础上，建立了齿轮系统的动力学模型，分析了不同程度点蚀齿轮系统的振动响应。结果表明:随着点蚀面积的增大，啮合刚度减小;驱动轮的啮合区域越靠近点蚀线，啮合刚度越小，导致振动响应加剧和周期性冲击;在时程图中，在啮合频率附近存在较小的杂散频率;在相图和庞加莱图中，轨迹和离散点聚集面积逐渐增大。

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引用次数: 9

Application of Axis Orbit Image Optimization in Fault Diagnosis for Rotor System 轴轨图像优化在转子系统故障诊断中的应用

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-31 DOI: 10.1155/2020/9540791

Xinyu Pang, Jie Shao, Xuanyi Xue, W. Jiang

The shape characteristic of the axis orbit plays an important role in the fault diagnosis of rotating machinery. However, the original signal is typically messy, and this affects the identification accuracy and identification speed. In order to improve the identification effect, an effective fault identification method for a rotor system based on the axis orbit is proposed. The method is a combination of ensemble empirical mode decomposition (EEMD), morphological image processing, Hu invariant moment feature vector, and back propagation (BP) neural network. Experiments of four fault forms are performed in single-span rotor and double-span rotor test rigs. Vibration displacement signals in the and directions of the rotor are processed via EEMD filtering to eliminate the high-frequency noise. The mathematical morphology is used to optimize the axis orbit including the dilation and skeleton operation. After image processing, Hu invariant moments of the skeleton axis orbits are calculated as the feature vector. Finally, the BP neural network is trained to identify the faults of the rotor system. The experimental results indicate that the time of identification of the tested axis orbits via morphological processing corresponds to 13.05 s, and the identification accuracy rate ranges to 95%. Both exceed that without mathematical morphology. The proposed method is reliable and effective for the identification of the axis orbit and aids in online monitoring and automatic identification of rotor system faults.

轴轨道的形状特征在旋转机械的故障诊断中起着重要的作用。然而，原始信号通常是杂乱的，这影响了识别的准确性和识别的速度。为了提高识别效果，提出了一种基于轴向轨道的转子系统故障识别方法。该方法将集合经验模态分解(EEMD)、形态学图像处理、Hu不变矩特征向量和BP神经网络相结合。在单跨转子和双跨转子试验台上进行了四种故障形式的试验。对转子各方向的振动位移信号进行EEMD滤波，消除高频噪声。利用数学形态学对轴轨进行优化，包括扩张和骨架操作。图像处理后，计算骨架轴轨道的Hu不变矩作为特征向量。最后，训练BP神经网络对转子系统进行故障识别。实验结果表明，形态学处理对被测轴轨的识别时间为13.05 s，识别正确率可达95%。两者在没有数学形态学的情况下都超过了这一数值。该方法可靠有效地实现了轴轨的识别，有助于转子系统故障的在线监测和自动识别。

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引用次数: 5

Study on Thermal Unstable Vibration of Rotor under Journal Whirl with Large Amplitude in Journal Bearing 轴颈轴承大振幅轴颈旋转下转子热不稳定振动研究

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-25 DOI: 10.1155/2020/1980759

Qilong Hu, Minjie Zhu, Jiangang Yang

To investigate the thermal unstable vibration caused by journal whirls with large amplitude in journal bearing, an analysis model of lubricant film thickness is established. The journal surface temperature distribution is solved, and the reason for journal surface temperature difference appearance and its influence on rotor vibration are analyzed. Taking a turbogenerator as an example, the journal surface temperature difference and the induced rotor thermal bending under synchronous whirl in the bearing are calculated. Meanwhile, an engineering vibration fault with its treatment is presented. Results show that, the journal surface circumferential temperature difference is caused by viscous shearing within lubricant film under journal whirls with large amplitude in journal bearing. The direction of temperature difference is related to the direction of unbalanced force acting on journal. The temperature difference causes rotor thermal bending, which can be converted to a thermal unbalance on the rotor. The rotor vibration is caused by both thermal and initial unbalance. When the rotor is running below or at the critical speed, the vibration is on the increase until it leads to instability of the rotor eventually. When the rotor is running above the critical speed, the rotor vibration fluctuates periodically. Reducing the initial (mechanical) unbalances decreases the rotor vibration and the journal surface circumferential temperature difference.

为了研究轴颈轴承内大振幅轴颈旋转引起的热不稳定振动，建立了润滑膜厚度的分析模型。解决了轴颈表面温度分布问题，分析了轴颈表面温差产生的原因及其对转子振动的影响。以某汽轮发电机为例，计算了轴承同步旋转作用下轴颈表面温差和诱导转子热弯曲。同时，介绍了一个工程振动故障及其处理方法。结果表明，轴颈剧烈旋转时，轴颈表面周向温差是由润滑膜内的粘性剪切引起的。温差的方向与作用在轴颈上的不平衡力方向有关。温差导致转子热弯曲，这可以转化为转子上的热不平衡。转子的振动是由热不平衡和初始不平衡共同引起的。当转子低于临界转速或处于临界转速时，振动不断增大，直至最终导致转子失稳。当转子运行在临界转速以上时，转子振动呈周期性波动。减少初始(机械)不平衡减少转子振动和轴颈表面周向温差。

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引用次数: 0

Combined Influence of Noncondensable Gas Mass Fraction and Mathematical Model on Cavitation Performance of Bearing 非凝性气体质量分数与数学模型对轴承空化性能的综合影响

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-23 DOI: 10.1155/2020/8409231

Li-li Wang, Zengkai Liu, Guo-teng Yuan, Yu-liang Wei

The presence of cavitation in the oil film seriously affects the bearing lubrication performance and bearing capacity. Now the research of this phenomenon mostly focuses on the model of Reynolds equation (R-E equation) or Navier-Stokes equation (N-S), the influence of the two computation models is less analyzed, and the effect of noncondensable gas (NCG) mass fraction on the bearing performance is seldom studied. In the manuscript, the cavitation mechanism is studied using the mixed model of three-dimensional N-S equation and Jakobsson-Floberg-Olsson (JFO) condition of two dimensional Reynolds equation, and the influence of rotational speed and NCG mass fraction on the cavitationoil film pressure, and bearing capacity was studied. The results show that the change trend of cavitation with the rotational speed is basically consistent for N-S equation and R-E equation. The bearing capacity calculated by N-S equation is greater than that calculated by R-E equation. The peak pressure and bearing capacity of film can be improved by increasing the NCG mass fraction of lubricant and rotational speed.

油膜中存在气蚀现象，严重影响轴承的润滑性能和承载能力。目前对这一现象的研究多集中在雷诺方程(R-E方程)或纳维-斯托克斯方程(N-S)模型上，对两种计算模型的影响分析较少，对不凝性气体质量分数对轴承性能的影响研究较少。本文采用三维N-S方程和二维Reynolds方程Jakobsson-Floberg-Olsson (JFO)条件的混合模型研究了空化机理，并研究了转速和NCG质量分数对空化油膜压力和承载能力的影响。结果表明，N-S方程和R-E方程的空化随转速的变化趋势基本一致。N-S方程计算的承载力大于R-E方程计算的承载力。增加润滑油的NCG质量分数和转速可以提高油膜的峰值压力和承载能力。

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引用次数: 0

Introductory Chapter: Rotating Machinery 导论章:旋转机械

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-08 DOI: 10.5772/intechopen.89276

G. Hailu

Rotating machinery or turbomachinery is a machine with a rotating component that transfers energy to a fluid or vice versa. Consequently, in a turbomachine there is energy transfer between the fluid and the rotor through dynamic interaction. Generally, if the energy transfer is from the rotor to the fluid, it is either a pump or fan. If the energy transfer is from the fluid to the rotor, then the machine is called turbine. We come across a turbomachine in everyday life. In fact, we come to use a turbomachine at least once in a day. When we dry our hair with a hair dryer, we are using a turbomachine. A hair dryer blows room temperature air over nichrome (alloy of nickel, chromium, and often iron) hot coils speeding up water evaporation. The important component of the hair dryer is the one that blows air (aka fan). This component is a turbomachine. Another commonly used household machine is the clothes washer. The washing machines need to drain the used dirty water and replace it with fresh water. To do so an important component of a washing machine is a pump that is used to remove the dirty water and supply fresh water. This pump is a turbomachine. If you own a car, you know how important it is to maintain an optimum operating temperature of your car. A water pump (hydrodynamic pump) is essential to your car’s operation. The pump ensures that the coolant keeps circulating through the engine block, hoses, and radiator and maintains an optimum operating temperature. Another everyday example is a kitchen vent. Fans inside the kitchen vent that pull the fumes in and push them via ductwork to the outside or through filters (that remove odors) and vent them back into the room are turbomachines. Besides a washing machine, a dishwasher, or a kitchen vent, when we are writing on our laptop/desktop, when we turn on the bathroom vent, and when we turn on a desktop fan or a ceiling fan, we are using turbomachines. All these components, the little fan in our computer which helps maintain the temperature of our computer or the ceiling fan which provides the thermal comfort needed in summer times, have certain types of geometry and shapes. You have probably noticed the difference in shapes and the number of blades between a windmill and modern wind turbine. These shapes and numbers are a result of careful analysis of fluid flow or air flow through these machines.

旋转机械或涡轮机械是一种具有旋转部件的机器，它将能量传递给流体，反之亦然。因此，在涡轮发电机中，流体和转子之间通过动态相互作用进行能量传递。一般来说，如果能量传递是从转子到流体，它要么是泵，要么是风扇。如果能量是从流体传递到转子，那么这种机器就叫做涡轮。我们在日常生活中会遇到涡轮机器。事实上，我们每天至少要用一次涡轮发电机。当我们用吹风机吹干头发时，我们使用的是涡轮发电机。吹风机将室温的空气吹过镍铬(镍、铬和铁的合金)热盘管，加速水分蒸发。吹风机的重要组成部分是吹风的部分(也就是风扇)。这个部件是一台涡轮机器。另一种常用的家用机器是洗衣机。洗衣机需要排出用过的脏水并用淡水代替。要做到这一点，洗衣机的一个重要组成部分是一个泵，用于去除脏水和供应淡水。这台泵是一台涡轮机器。如果你有一辆车，你就会知道保持汽车的最佳工作温度是多么重要。水泵(水动力泵)对汽车的运转是必不可少的。该泵确保冷却液通过发动机机体、软管和散热器保持循环，并保持最佳工作温度。另一个日常的例子是厨房的通风口。厨房通风口里的风扇把烟雾吸进来，通过管道系统把它们推到外面，或者通过过滤器(去除气味)把它们放回房间，这些风扇就是涡轮机器。除了洗衣机、洗碗机或厨房通风口，当我们在笔记本电脑/台式电脑上写字时，当我们打开浴室的通风口时，当我们打开台式风扇或吊扇时，我们使用的是涡轮机器。所有这些部件，比如电脑里帮助保持电脑温度的小风扇，或者在夏天提供热舒适的吊扇，都有特定的几何形状。你可能已经注意到风车和现代风力涡轮机在形状和叶片数量上的不同。这些形状和数字是仔细分析通过这些机器的流体流动或空气流动的结果。

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引用次数: 0

Advance Measurement Techniques in Turbomachines 涡轮机械的先进测量技术

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-08 DOI: 10.5772/intechopen.85910

Fangyuan Lou

This chapter focuses on advanced measurement techniques that have been used in applications of turbomachines including temperature measurements, pressure measurements, velocity measurements, and strain/stress measurements. Though the measurement techniques are fundamentally the same as those used in other applications, the unique features associated with turbomachines place challenges in implementing these techniques. This chapter covers the fundamental working principles of individual measurement technique as well as the highlights of its application in turbomachines.

本章重点介绍了涡轮机械应用中使用的先进测量技术，包括温度测量、压力测量、速度测量和应变/应力测量。虽然测量技术基本上与其他应用中使用的测量技术相同，但与涡轮机器相关的独特功能为实现这些技术带来了挑战。本章涵盖了单个测量技术的基本工作原理，以及其在涡轮机械中的应用亮点。

引用次数: 0

CD4+ cell count stratification to guide tuberculosis preventive therapy for people living with HIV. 对 CD4+ 细胞计数进行分层，为艾滋病病毒感染者的结核病预防治疗提供指导。

IF 3.4 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2020-01-01 DOI: 10.1097/QAD.0000000000002398

Lelia H Chaisson, Valeria Saraceni, Silvia Cohn, Dena Seabrook, Solange C Cavalcante, Richard E Chaisson, Jonathan E Golub, Betina Durovni

Objectives: In 2018, Brazilian guidelines changed to recommend tuberculosis (TB) preventive therapy for all people with HIV and a CD4 cell count 350 cells/μl or less, but only for those with a positive tuberculin skin test (TST) if CD4 cell count is than 350 cells/μl. We determined the potential effectiveness of CD4-based guidelines for TB testing and preventive therapy.

Design: Secondary analysis of the stepped-wedge, cluster-randomized THRio trial for isoniazid preventive therapy (IPT).

Methods: We analyzed data from 4114 newly registered patients with HIV in 29 clinics followed until TB diagnosis, death, or administrative censoring. We compared incidence rates of TB and TB/death between CD4, TST, IPT, and antiretroviral therapy categories.

Results: Initial CD4 cell count was 350 cells/μl or less in 2138 (52%) and more than 350 cells/μl in 1976 (48%) patients. TST was performed for 2922 (71%), of whom 657 (16%) were TST-positive [278 (13%) CD4 ≤ 350 vs. 379 (19%) CD4 > 350]. A total of 619 (15%) received IPT and 2806 (68%) received antiretroviral therapy. For patients with CD4 cell count 350 cells/μl or less who did not receive IPT, the incidence rate of TB was 1.79/100 person-years (pys) and TB/death was 3.89/100 pys. For patients with CD4 cell count more than 350 who did not receive IPT, the incidence rates of TB and TB/death were 0.57/100 and 1.49/100 pys for TST-negatives, and 1.05/100 and 1.64/100 pys for TST-unknowns.

Conclusion: TB incidence was high among all patients who did not receive IPT, including those with CD4 cell count more than 350 cells/μl and negative or unknown TST results. TB preventive therapy should be provided to all people living with HIV in medium burden settings, regardless of CD4 cell count and TST status.

目的：2018 年，巴西指南做出改变，建议对所有 CD4 细胞计数为 350 cells/μl 或更低的艾滋病病毒感染者进行结核病（TB）预防治疗，但如果 CD4 细胞计数高于 350 cells/μl，则仅对结核菌素皮试（TST）阳性者进行预防治疗。我们确定了基于 CD4 细胞数的结核病检测和预防治疗指南的潜在有效性：设计：对异烟肼预防性疗法（IPT）的阶梯式、分组随机化 THRio 试验进行二次分析：我们分析了 29 家诊所中 4114 名新登记的 HIV 感染者的数据，并对其进行了随访，直至肺结核确诊、死亡或行政剔除。我们比较了 CD4、TST、IPT 和抗逆转录病毒疗法类别之间的结核病发病率和结核病/死亡率：初始 CD4 细胞计数为 350 cells/μl 或以下的患者有 2138 人（52%），超过 350 cells/μl 的患者有 1976 人（48%）。对 2922 人（71%）进行了 TST 检测，其中 657 人（16%）TST 阳性[278 人（13%）CD4 ≤ 350，379 人（19%）CD4 > 350]。共有 619 人（15%）接受了 IPT 治疗，2806 人（68%）接受了抗逆转录病毒治疗。对于 CD4 细胞计数为 350 cells/μl 或更低且未接受 IPT 的患者，结核病发病率为 1.79/100人-年，结核病/死亡为 3.89/100人-年。对于 CD4 细胞计数超过 350 且未接受 IPT 的患者，TST 阴性患者的结核病发病率和结核病/死亡病例分别为 0.57/100 人/年和 1.49/100 人/年，TST 未知患者的结核病发病率和结核病/死亡病例分别为 1.05/100 人/年和 1.64/100 人/年：结论：在所有未接受 IPT 的患者中，包括 CD4 细胞计数超过 350 cells/μl 和 TST 结果为阴性或未知的患者，结核病发病率都很高。无论 CD4 细胞计数和 TST 检测结果如何，都应为中等负担环境中的所有艾滋病病毒感染者提供结核病预防治疗。

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引用次数: 0

Uncertainty Analysis Techniques Applied to Rotating Machines 不确定性分析技术在旋转机械中的应用

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2019-10-30 DOI: 10.5772/intechopen.83828

F. A. Lara-Molina, A. Dourado, A. Cavalini, V. Steffen

This chapter presents the modeling procedure, numerical application, and experimental validation of uncertain quantification techniques applied to flexible rotor systems. The uncertainty modeling is based both on the stochastic and fuzzy approaches. The stochastic approach creates a representative model for the flexible rotor system by using the stochastic finite element method. In this case, the uncertain parameters of the rotating machine are characterized by homogeneous Gaussian random fields expressed in a spectral form by using the Karhunen-Loève (KL) expansion. The fuzzy approach uses the fuzzy finite element method, which is based on the α -level optimization. A comparative study regarding the numerical and experimental results obtained from a flexible rotor test rig is analyzed for the stochastic and fuzzy approaches.

本章介绍了不确定量化技术应用于柔性转子系统的建模过程、数值应用和实验验证。不确定性建模是基于随机和模糊两种方法。随机方法采用随机有限元法建立了柔性转子系统的代表性模型。利用karhunen - lo (KL)展开将旋转机械的不确定参数用齐次高斯随机场表示为谱形式。模糊方法采用基于α级优化的模糊有限元方法。对某柔性转子试验台的数值和实验结果进行了比较，分析了随机方法和模糊方法的优缺点。

引用次数: 1

Methodology for Abrasive Wear Evaluation in Elevator Stage Centrifugal Pump Impellers 提升级离心泵叶轮磨料磨损评价方法

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2019-09-27 DOI: 10.5772/intechopen.83794

R. O. P. Serrano, J. G. Moreira, A. L. P. D. Castro, M. A. Pinto, Edna M. de F. Viana, C. B. Martinez

The abrasion resistance of the impellers depends on the characteristics of the materials used in their manufacture. In this work, a methodology is proposed for the evaluation of the abrasive wear of the plates of the centrifugal pump impellers, used in the gross water infrastructure station (GWIS) of sedimentary rivers, due to the sediment load variation and the river fluviometric dimension. In order to determine the wear mode and the relationship of the material-specific wear coefficient (K), due to the sediment concentration, a rotating ball abrasometer test was performed on SAE 8620, gray cast iron (GCI), and nodular cast iron (NCI), used in the manufacture of impellers. As an abrasive suspension, the concentrations of 1, 2, 3, 5, and 10 g L (cid:1) 1 of sediment were used in distilled water. The wear volume as a function of the relative velocity of the mixture in relation to the impeller blades was estimated mathematically. The results show that: i) The abrasive capacity of the sediments in different concentrations; ii) SAE 8620 steel was more resistant to abrasive wear; and iii) the rotational control of the pump as a function of sediment concentration and river level showed the possibility of reducing wear by 30%.

叶轮的耐磨性取决于制造它们所用材料的特性。本文提出了一种基于泥沙负荷变化和河流流量维数的沉积河流总水基础设施站(GWIS)用离心泵叶轮板磨粒磨损评价方法。为了确定泥沙浓度对sae8620、灰口铸铁(GCI)和球墨铸铁(NCI)的磨损模式和材料特定磨损系数(K)之间的关系，采用旋转球磨耗仪对叶轮使用的sae8620、灰铸铁(GCI)和球墨铸铁(NCI)进行了试验。作为磨料悬浮液，浓度分别为1、2、3、5和10 g L (cid:1) 1的沉淀物在蒸馏水中使用。用数学方法估计了混合液相对于叶轮叶片的相对速度对磨损量的影响。结果表明:1)不同浓度沉积物的磨粒能力;ii) SAE 8620钢更耐磨料磨损;iii)泵的旋转控制随泥沙浓度和水位的变化表明有可能减少30%的磨损。

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引用次数: 1

Design and Production of Innovative Turbomachinery Components via Topology Optimization and Additive Manufacturing 通过拓扑优化和增材制造设计和生产创新涡轮机械部件

IF 0.9 Q4 ENGINEERING, MECHANICAL

International Journal of Rotating Machinery

Pub Date : 2019-09-02 DOI: 10.1155/2019/9546831

E. Meli, A. Rindi, A. Ridolfi, R. Furferi, F. Buonamici, G. Iurisci, S. Corbò, F. Cangioli

The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the potential of Topology Optimization (TO) and Additive Manufacturing (AM). The method envisages the use of TO to define the best configuration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight. Eventually, the topology-optimized component is manufactured by using appropriate materials that can guarantee valid mechanical performances. The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness of a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and expanders, its application on rotor and stator components might unlock several benefits: tuning the natural frequencies, a reduction in the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing a single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing resources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are essential in the Oil and Gas context, when dealing with new projects but also for service operations.

本文提出了一种利用拓扑优化(to)和增材制造(AM)的潜力来设计和制造优化涡轮机械部件的方法。该方法设想使用TO在静态和动态行为方面定义旋转部件的最佳配置，从而减少总重量。最终，通过使用适当的材料来制造拓扑优化的部件，以保证有效的机械性能。将该方法应用于离心压缩机的二维叶轮，验证了基于to + am方法的有效性。虽然这种方法以前从未广泛用于离心压缩机和膨胀机，但它在转子和定子部件上的应用可能会带来几个好处:调整固有频率，降低应力水平，减轻旋转部件的重量。这些目标可以单独或组合实现，执行单个分析或多个分析优化。最后，引入增材制造技术作为标准制造资源，可以在生产时间和部件可用性方面带来明显的好处。在油气行业中，无论是处理新项目还是服务操作，这些方面都是必不可少的。

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引用次数: 12