离心齿式压缩机频谱分析及故障诊断

对离心齿式压缩机因振动较大导致报警停车的联锁故障进行了研究。采用多通道同步数据采集系统对压缩机进行了频谱分析,主要采集了振动幅值的时域波形、频谱特征及轴心轨迹,分析数据可知高速转子存在不平衡的情况和摩擦故障。对离心齿式压缩机主机进行拆箱检查,发现大齿轮和高速转子的推力盘存在摩擦刮痕,验证了分析结果,重新校核转子动平衡和修复转子后机组运行正常。频谱分析为机组故障的解决提供了有效依据和方法。

透平式离心压缩机的喘振危害消除

透平式离心压缩机本身具有叶轮尺寸小且转速高、稳定与可靠性较强的特点,但这些特点在保证透平式离心压缩机拥有优秀性能的同时,也对透平式离心压缩机的喘振控制提出了较高要求。就透平式离心压缩机的喘振危害消除进行了具体研究。

浅谈透平式离心压缩机的喘振原因分析及策略

涡轮膨胀机的离心压缩机具有叶轮尺寸小,转速高,稳定性和可靠性高的特点,但这些特征保证了涡轮膨胀机的出色性能,并建议对涡轮离心压缩机进行喘振控制。涡轮离心压缩机的喘振消除已得到专门研究。

悬臂式单轴离心压缩机试车方案研究与应用

鉴于悬臂式单轴离心的特殊性,为确保在厂内的试车顺利进行,我们通过多年来累的经验,特制定出一套切实可行的试车方案。

汽轮机驱动离心式压缩机的调节系统设计

离心式压缩机因其结构简单紧凑、气体输送能力大、运行效率高、平均气体无油等优点,被广泛应用于石油、化工、制冷等领域。满足各类机械设备传动的控制要求。利用动能转换原理提高设备内部气体压力,保持内外设备稳定运行。本文分析了离心式压缩机的工作原理和特点,本文介绍了离心式压缩机的结构和工作原理,并进一步分析了日常运行中常见的故障及处理措施,以便对现场设备的安装、维护和运行情况作一概述。

大型空分装置配套离心压缩机组的综合选评

通过对多轴齿轮式多级离心式压缩机组和单轴多级离心式压缩机组的压缩机组型式、驱动机型式、外形尺寸和厂房空间需求、投资费用等方面的综合技术选评比较可知,本次4.2万系列空分项目所选用的原料空压机组和增压机组,应优先选用多轴齿轮式多级离心压缩机组。

采用复约束旋转模态子结构法分析离心叶轮振动特性

根据叶轮周向循环对称的特点，采用回转周期结构的复约束及旋转模态子结构方法，将计算简化为针对一个叶道进行，从而达到降阶的目的．为了解决采用复约束而出现的广义复Ｈｅｒｍｉｔｅ矩阵特征值问题，提出了一个改进的子空间迭代方法，并对Ｊａｃｏｂｉ迭代作出了相应的修改．最后，用该模型对一个实际离心叶轮振动特性进行了分析。

整体齿轮增速式离心压缩机振动耦合动力特性研究

以一台在役的六级整体齿轮增速式离心压缩机为研究对象,基于转子动力学和齿轮动力学理论,建立了全自由度齿轮-轴承-转子耦合系统有限元模型。计算了考虑齿轮啮合接触的转子系统固有频率、模态振型和不平衡响应,得出了这种复杂轴系的模态特征与振动传递特性。在此基础上,研究了不同支撑型式下转子振动响应特性,并探讨了齿轮螺旋角对转子振动的影响。研究结果表明,耦合轴系的固有频率和不平衡响应峰值都有所增大;转子系统在可倾瓦轴承支撑下,无论过临界还是工作转速振动幅值均较低;当齿轮螺旋角为15°时,转子振动幅值最小。

Prediction of Cracking Gas Compressor Performance and Its Application in Process Optimization

Cracking gas compressor is usually a centrifugal compressor. The information on the performance of a centrifugal compressor under all conditions is not available, which restricts the operation optimization for compressor. To solve this problem, two back propagation (BP) neural networks were introduced to model the performance of a compressor by using the data provided by manufacturer. The input data of the model under other conditions should be corrected according to the similarity theory. The method was used to optimize the system of a cracking gas compressor by embedding the compressor performance model into the ASPEN PLUS model of compressor. The result shows that it is an effective method to optimize the compressor system.

Characteristics of the Water Steam Turbocompressors Applied in the Concentrator Systems

The main geometrical and operating parameters of the water steam centrifugal compressors working in various concentrator operating conditions are realized in this paper. The interdependence between centrifugal stage pressure ratio, peripheral Mach number and impeller peripheral speed, as well the influence of the concentrator system capacity on the dimensions of the centrifugal compressor are determined to obtain the range of reasonable usage of the centrifugal thermocompression systems in the industrial concentrators. The high peripheral impeller speed, high Mach number and high pressure ratio cause separated jet-wake flow and transonic flow phenomena in the water steam centrifugal compressor flow field. The calculating methods for 3-D viscid unsteady transonic fluid flows in the turbocompressors are discussed and the results of CFD simulations and experimental investigations are used for optimal design of the water steam centrifugal compressor flow field. The application of the centrifugal compressor in the industrial concentrators with thermocompression systems and the influence on the energy efficiency of the systems are analyzed. Significant increment of the energy efficiency of the industrial concentrators can be achieved by introduction of the thermocompression systems.

Experimental study on barrel viscous dampers and pipe hoops in pipeline vibration reduction

The centrifugal air compressor outlet pipeline vibration was not decreased after barrel viscous dampers were installed in a petrochemical plant in Tianjin.A pipeline-damper experiment apparatus was built for studying the influence factors of the barrel viscous damper and pipe hoop in pipeline vibration reduction.The performance of the damper under different frequency and amplitude was researched respectively,the results showed that damping effect dependsed mainly on frequency and was not related to amplitude.Damper will fail when its vibration frequency exceeds its limit working frequency which was 40 Hz in test.The mechanical properties and energy dissipation were analyzed by using the Maxwell model,which explains experimental results well.According to damping effect and calculation of stiffness with ANSYS in different hoop width,hoop stiffness should match pipe stiffness and keep uniform along transfer path.Damping effect will get worse when local stiffness is too small or too large.Finally,the outlet pipeline vibration was decreased by 70%after using appropriate pipe hoop width and replacing the original damping liquid.

Design of Process Centrifugal Compressor： an Adapted Algorithm

Considering the essential and influential role of centrifugal compressors in a wide range of industries makes most of engineers research and study on design and optimization of centrifugal compressors. Centrifugal compressors are the key to part ofoil, gas and petrochemical industries as well as gas pipeline transports. Since complete 3D design of the compressor consumes a considerable amount of time, most of active companies in the field, are profoundly interested in obtaining a design outline before taking any further steps in designing the entire machine. In this paper, a numerical algorithm, named ACDA （adapted compressor design algorithm） for fast and accurate preliminary design of centrifugal compressor is presented. The design procedure is obtained under real gas behavior, using an appropriate equation of state. Starting from impeller inlet, the procedure is continued on by resulting in numerical calculation for other sections including impeller exit, volute and exit diffuser. Clearly, in any step suitable correction factors are employed in order to conclude in precise numerical results. Finally, the achieved design result is compared with available reference data.

Effect of Diffuser Vane Shape on the Performance of a Centrifugal Compressor Stage

The present paper reports the results of experimental investigations on the effect of diffuser vane shape on the performance of a centrifugal compressor stage. These studies were conducted on the chosen stage having a back- ward curved impeller of 500 turn tip diameter and 24.5 mm width and its design flow coefficient is Фd=0.0535. Three different low solidity diffuser vane shapes namely uncarnbered aerofoil, constant thickness flat plate and circular arc cambered constant thickness plate were chosen as the variants for diffuser vane shape and all the three shapes have the same thickness to chord ratio （t/c=0.1）. Flow coefficient, polytropic efficiency, total head coeffi- cient, power coefficient and static pressure recovery coefficient were chosen as the parameters for evaluating the effect of diffuser vane shape on the stage performance. The results show that there is reasonable improvement in stage efficiency and total head coefficient with the use of the chosen diffuser vane shapes as compared to conven- tional vaneless diffuser. It is also noticed that the aero foil shaped LSD has shown better performance when com- pared to flat plate and circular arc profiles. The aerofoil vane shape of the diffuser blade is seen to be tolerant over a considerable range of incidence.

Effects of Tapered Diffuser Vane on the Flow Field and Noise of a Centrifugal Compressor

The effects of a three-dimensional tapered diffuser vane on the flow field and noise radiated from a centrifugal compressor are investigated by both CFD analyses and experiments. Tapered diffuser vanes are very useful not only for the reduction of the interaction tone noise but also for the improvement of the pressure recovery characteristics within the diffuser passage. By using tapered diffuser vanes, the interaction area between the impeller-discharge flow and diffuser vanes becomes small, and then the noise level of the discrete tone can be reduced remarkably as a result. Furthermore, by utilizing the visualization technique of vortical structures based on the CFD results, the scale of vortex shedding leaving from the leading edge of the diffuser vanes is found to be contracted and a tendency for the turbulence level to decrease is observed. This may be the cause of the attenuation of broadband noise components. The secondary flow, which is considered to be an obstruction of diffuser pressure recovery, can also be suppressed by the tapered diffuser vanes, and the pressure decrease observed in the throat part of the diffuser passage is further reducible.

Temporal Behaviour of a Corner Separation in a Radial Vaned Diffuser of a Centrifugal Compressor Operating near Surge

The temporal behaviour of a flow separation in the hub-suction side comer of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical re- sults is confn＇med by comparison with experimental unsteady pressure measurements. An analysis of the instan- taneous skin-friction pattern and particles trajectories is presented. It highlights the topology of the separation and its temporal behaviour. The major result is that, despite of a highly time-dependent core flow, the separation is found to be a ＂fixed unsteady separation＂ characterized by a fixed location of the main saddle of the separation but an extent of the stall region modulated by the pressure waves induced by the impeller-diffuser interaction.

Multi-point Optimization of Recirculation Flow Type Casing Treatment in Centrifugal Compressors

High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. R is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

Design and Optimization of a Single Stage Centrifugal Compressor for a Solar Dish-Brayton System

According to the requirements of a solar dish-Brayton system,a centrifugal compressor stage with a minimum total pressure ratio of 5,an adiabatic efficiency above 75% and a surge margin more than 12% needs to be designed.A single stage,which consists of impeller,radial vaned diffuser,90° crossover and two rows of axial stators,was chosen to satisfy this system.To achieve the stage performance,an impeller with a 6:1 total pressure ratio and an adiabatic efficiency of 90% was designed and its preliminary geometry came from an in-house one-dimensional program.Radial vaned diffuser was applied downstream of the impeller.Two rows of axial stators after 90° crossover were added to guide the flow into axial direction.Since jet-wake flow,shockwave and boundary layer separation coexisted in the impeller-diffuser region,optimization on the radius ratio of radial diffuser vane inlet to impeller exit,diffuser vane inlet blade angle and number of diffuser vanes was carried out at design point.Finally,an optimized centrifugal compressor stage fulfilled the high expectations and presented proper performance.Numerical simulation showed that at design point the stage adiabatic efficiency was 79.93% and the total pressure ratio was 5.6.The surge margin was 15%.The performance map including 80%,90% and 100% design speed was also presented.

A model for parameter estimation of multistage centrifugal compressor and compressor performance analysis using genetic algorithm

A model for performance prediction of multistage centrifugal compressor is proposed. The model allows the users to predict the compressor performance, e.g. pressure ratio, efficiency and losses using the compressor geometric information and speed by a stage stacking calculation based on the characteristics of each stage. To develop the compressor elemental stage charac- teristics, the compressor losses, such as incidence losses and friction losses, are mathematically modeled. For a composite sys- tems, for instance a gas turbine power plant, the performance of the multistage centrifugal compressor can be evaluated. Since some important parameters of the compressor model, e.g., the slip factor or, shock loss coefficient （and reference diameter DI, are hard to be determined by empirical laws, a genetic algorithm （GA） is used to solve the parameter estimation problem of the proposed model, and in turn the compressor performance analysis and parameters study are performed. The surge line for the multistage centrifugal compressor can also be determined from the simulation results. Furthermore, the model presented here provides a valuable tool for evaluating the multistage centrifugal compressor performance as a function of various operation parameters.

Non-axisymmetric Flow Characteristics in Centrifugal Compressor

The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.