用HHT变换处理离心压缩机喘振试验数据

为了提取离心压缩机早期喘振特征频率,在对信号进行小波包降噪抽样后,利用Hilbert-Huang变换(HHT)进行信号特征提取。通过经验模态分解(EMD)得到若干固有模态函数(IMF),然后利用相关系数法对IMF进行筛选。通过趋势项和原始信号对比可知压缩机流量减少是造成振动的主因,最后对有效IMF信号进行Hilbert变换,并求其边际谱,提取压缩机喘振频率为7.3Hz。     

离心压缩机的喘振分析与控制

对离心压缩机输气系统工程中喘振产生的机理进行了系统的分析，在此基础上给出了喘振发生的条件与判断方法，并提出了采用人工智能控制算法对喘振进行控制的解决方案。     

乙烯压缩机防喘振控制

介绍了离心式压缩机工作过程中喘振产生的机理,喘振的危害。分析了造成喘振的主要因素,并对常用的防喘振控制方法进行了比较和分析。详细介绍了某装置压缩机防喘振控制的具体实现。     

Cavitation pulse extraction and centrifugal pump analysis

This study extracted cavitation pulses from hydrophone signals sampled in a centrifugal pump and analyzed their characteristics. The modified and simplified Empirical mode decomposition (EMD) algorithm was proposed for extracting cavitation pulses from strong background noise. Experimental results showed that EMD can effectively suppress noise and obtain clear cavitation pulses, facilitating the identification of the number of pulses associated with the degree of cavitation. The cavitation characteristics were modeled to predict the value of incipient cavitation. Then, we proposed a method for detecting the wear of the impeller surface. That is, the information on the impeller surface of the centrifugal pump, including the roughness of the impeller surface and its wear trends, were quantified based on the net positive suction head available of incipient cavitation. The findings indicate that the proposed technique is suitable for condition monitoring of the pump.     

离心空压机喘振与控制

由于离心式空压机结构简单,排气量大,效率高,目前广泛应用于冶金、化工以及空分等行业。但离心式空压机在运行过程中,对气体的压力、流量以及温度变化较为敏感,容易发生"喘振"现象。离心空压机喘振具有较大的危害性,是造成空压机损坏的主要原因之一。因此,研究和预防喘振的发生,弄清和掌握喘振的机理,采取有效控制措施避免喘振的发生是离心空压机控制中的重要任务。     

离心压缩机防喘振控制系统设计

在分析离心压缩机管网特性的基础上,对其自动控制系统的组成原理和功能设计,特别是防喘振控制进行了比较系统的阐述。举例说明了以上位工控机、三重化冗余PLC和以太网为架构的分散控制系统的设计方案。     

离心式压缩机的喘振分析与控制

利用离心式压缩机性能曲线及管路特性曲线的特点，结合加氢装置解析气压缩机实际情况，对离心式压缩机的喘振现象进行分析，并提出了防喘振措施。     

基于TS3000系统的延迟焦化富气压缩机防喘振控制探讨

介绍了TS3000基本软硬件配置以及三冗余原理,论述了压缩机发生喘振的原理,压缩机防喘振控制的3种基本方法。介绍了九江石化延迟焦化装置富气压缩机防喘振控制的原理和实现方式,分析了防喘振阀的动作过程,总结了该套系统在实际应用中的效果。     

天然气管道离心压缩机喘振与预防

针对天然气管道压缩机喘振产生的原因进行了分析,提出了预防喘振的方法。     

空压机防喘振控制在40 000空分中的应用

介绍了离心式压缩机产生喘振的现象和原因,阐述了在首套国产大型40 000空分装置中离心式空压机防喘振的方法及防喘振控制方案的措施.实践证明该控制自投运来从未发生喘振,运行安全可靠,这说明了控制方案是可行的,是值得推广的一种控制方案.     

离心式压缩机振动影响因素及控制浅析

离心式压缩机作为一种速度式压缩机,具有流量大,转速高,结构紧凑,运转可靠,易损件少等优点,但同时存在喘振及高转速下的振动等问题。对此,从喘振控制及运行振动控制两方面进行了分析与探讨。     

Experiment and surge analysis of centrifugal two-stage turbocharging system

To study a centrifugal two-stage turbocharging system’s surge and influencing factors, a special test bench was set up and the system surge test was performed. The test results indicate that the measured parameters such as air mass flow and rotation speed of a high pressure (HP) stage compressor can be converted into corrected parameters under a standard condition according to the Mach number similarity criterion, because the air flow in a HP stage compressor has entered the Reynolds number (Re) auto-modeling range. Accordingly, the reasons leading to a two-stage turbocharging system’s surge can be analyzed according to the corrected mass flow characteristic maps and actual operating conditions of HP and low pressure (LP) stage compressors.     

Experimental and Computational Analysis of the Unstable Flow Structure in a Centrifugal Compressor with a Vaneless Diffuse

The unstable flow phenomena in compressors, such as stall and surge, are closely related to the e ciency and the operating region. It is indispensable to capture the unstable flow structure in compressors and understand the mechanism of flow instability at low flow rates. Cooperated with the manufacturer, an industrial centrifugal compressor with a vaneless di user is tested by its performance test rig and our multi-phase dynamic measurement system. Many dynamic pressure transducers are circumferentially mounted on the casing surface at seven radial locations, spanning the impeller region and the di user inlet region. The pressure fields from the design condition to surge are measured in details. Based on the multi-phase dynamic signals, the original location of stall occurring can be determined. Meanwhile, the information of the unstable flow structure is obtained, such as the circumferential mode and the propagating speed of stall cells. To get more details of the vortex structure, an unsteady simulation of this tested compressor is carried out. The computational result is well matched with the experimental result and further illustrates how the unstable flow structure in the impeller region gradually a ects the stability of the total machine at low flow rates. The dynamic mode decomposition(DMD) method is applied to get the specific flow pattern corresponding to the stall frequency. Both experimental and computational analysis show that the flow structure at a particular radial location in the impeller region has a great impact on the stall and surge. Some di erences between the computational and experimental result are also discussed. Through these two main analytical methods, an insight into the unstable flow structure in an industrial compressor is gained. The result also plays a crucial role in the guidance of the compressor stabilization techniques.     

Experiment and surge analysis of centrifugal two-stage turbocharging system

To study a centrifugal two-stage turbocharging system’s surge and influencing factors, a special test bench was set up and the system surge test was performed. The test results indicate that the measured parameters such as air mass flow and rotation speed of a high pressure (HP) stage compressor can be converted into corrected parameters under a standard condition according to the Mach number similarity criterion, because the air flow in a HP stage compressor has entered the Reynolds number (Re) auto-modeling range. Accordingly, the reasons leading to a two-stage turbocharging system’s surge can be analyzed according to the corrected mass flow characteristic maps and actual operating conditions of HP and low pressure (LP) stage compressors.     

磁悬浮高速离心式鼓风机的喘振检测

针对磁悬浮高速离心式鼓风机的喘振问题,提出了一种基于磁悬浮轴承的喘振检测方法。该方法采用通用同频陷波器滤除转子位移中的同频分量,消除了同频扰动对喘振检测的影响;通过分析不同收敛因子对喘振频率估计的作用,基于自适应估计提出了变收敛因子的喘振频率和幅值估计方法,减小了低频信号的干扰,提高了喘振信号检测的快速响应能力。最后,分析了改进检测算法的收敛性,并在100kW磁悬浮离心式鼓风机测试系统上进行了实验验证。实验结果表明,改进后的喘振检测算法可在喘振发生前检测出喘振先兆旋转失速信号,在喘振发生0.23s内检测出喘振信号,较改进前的检测结果提高了2.6s。该检测方法无需外加其它检测单元,算法简单、快速,计算量小、并可有效地反映喘振发生过程中频率与振幅的变化。     

离心式压缩机轴振动超标的原因分析

介绍了H400—6．5／0．97型离心式空气压缩机发生喘振的外部现象，简单分析了喘振原因，在对空压机进行解体检查，检测后发现了引起轴振动较大的原因，提出了所采取的措施，最后得出试运转正常的结论。     

Gearbox fault diagnosis using empirical mode decomposition and Hilbert spectrum

The empirical mode decomposition (EMD) and Hilbert spectrum are a new method for adaptive analysis of non-linear and non-stationary signals. This paper applies this method to vibration signal analysis for localised gearbox fault diagnosis. We first study the properties of the recently developed B-spline EMD as a filter bank, which is helpful in understanding the mechanisms behind EMD. Then we investigate the effectiveness of the original and the B-spline EMD as well as their corresponding Hilbert spectrum in the fault diagnosis. Vibration signals collected from an automobile gearbox with an incipient tooth crack are used in the investigation. The results show that the EMD algorithms and the Hilbert spectrum perform excellently. They are found to be more effective than the often used continuous wavelet transform in detection of the vibration signatures.     

叶轮机械叶片的计算机辅助设计

本文讨论了基于叶轮机械三元流动通用理论的叶型设计及优化过程,改进了叶型积迭和叶片加工用平面样板曲线的计算方法,发展了绘制叶片和叶轮的各种平面投影、空间轴测投影及消除被遮盖的隐藏线的计算机绘图方法,并已获得实际应用。本文给出了典型的实例。     

基于MDO方法的离心式压气机设计系统

针对离心式压气机设计中存在流-热-固耦合的问题,文中进行离心式压气机的多学科设计优化研究,基于多学科可行方法,建立离心式压气机的多学科设计优化系统.利用非均匀有理B样条曲线和五次多项式,分别构建径流式叶片型线和扩压器叶片型线,通过特征造型技术,建立离心式压气机参数化模型.采用线性插值方法和网格重生成方法,完成对温度、气压和变形耦合信息传递.在压气机参数化建模和多学科耦合分析的基础上,以总压比、等熵效率和流量为优化目标,对某离心式压气机进行设计优化,实现其综合性能的改善.所建多学科设计优化系统可以推广到其他多场耦合系统的设计.     

离心压缩机现场动平衡

本文结合多次大型离心压缩机现场动平衡实践,对可以进行现场动平衡的离心压缩机进行了归纳,对三圆法和矢量法进行了总结,通过实践证明柔性转子在工作转速下进行现场动平衡,能够有效的降低不平衡引起的振动。