影响离心式空压机喘振的运行因素与预防

本文针对离心式空压机喘振这一常见故障,通过对离心式空压机的工作原理和喘振产生机理的阐述,重要分析了离心式空压机在日常运行过程中引发喘振的因素,并就离心式空压机喘振的预防提出相应的措施,对预防离心式空压机的喘振有一定的帮助。     

离心式压缩机防喘振方法的应用现状

喘振问题一直是困扰离心式压缩机实现安全、经济、平稳运行的难题。喘振现象会造成离心式压缩机出现周期性的物料倒流或者是由于压力变化发生强烈的波动,同时还会产生热应力和很大的振动,严重时可能会缩短设备寿命,造成机组的部件损坏,还可能造成严重的事故。针对以上问题,就离心式压缩机防喘振技术的应用进行了深入的探讨,对传统的固定极限流量法和可变极限流量法,以及新型的模糊控制法、压缩机串并联控制、预估防喘振控制等进行了分析比较。为开发出更好的防喘振技术提供借鉴。     

离心式空压机喘振原因分析与处理

在离心机调试过程中,频繁遇到的离心式空压机喘振保护停机问题,在进行了故障分析、原因查找后,经过与厂家人员协调后,终于将故障问题解决,使离心式空压机能够正常运行,确保项目按期竣工、验收,正常向炼油事业部供风。     

NF-6风洞AV90-2轴流压缩机喘振曲线测试研究

文章对NF-6风洞AV90-2轴流压缩机防喘振监控系统进行了分析研究.重点讨论了防喘振机理、监控系统结构和喘振测试方法,并且基于此系统进行了AV90-2轴流压缩机喘振曲线测试.结果表明:①该防喘振监控系统能够保障风洞安全运行要求,为压缩机的喘振曲线测试和风洞正常实验奠定了坚实的基础;②采用体积流量作为喘振曲线的控制流量是合理的,常压和增压的喘振边界点几乎重合;③常压防喘振曲线可以保障风洞在不同总压下的安全运行.     

离心式压缩机防喘振控制系统在海上油田的应用

与渤海油田常用的往复活塞式压缩相比,离心式压缩机具有单机处理量大、排气稳定、出口压力大等优点。在分析离心式压缩机喘振原理的基础上,采用CCC防喘振控制系统,对防喘振控制算法进行优化,以减弱入口条件对喘振曲线的影响,提高控制精度。控制系统采用单机配置、中心协调的策略,主控制器采用冗余架构,单机控制器采用单机架构并通过高速网络与主控制器进行通讯传输。控制系统稳定性和可靠性良好。     

天然气离心式压缩机防喘振控制研究

离心式压缩机是天然气输送企业中的关键设备,对于企业是正常运行生产发挥着重要的作用,然而对于这类压缩机来说,有个特殊的问题难以避免,就是设备在运行过程中,压缩机会产生不同程度上的喘振,这种喘振不仅会影响离心式压缩机的运行状态,使压缩机性能显著恶化,还会缩短设备的运行寿命.因此,防喘振控制是压缩机控制中的重中之重.本文使以离心式压缩机喘振的产生为研究基点,分析了离心式压缩机喘振的产生的原因及影响因素,并对离心式压缩机进行防喘振控制的主要方法进行了阐述.     

卷烟厂工艺除尘风机喘振分析与控制方法

从离心风机特性曲线与管路特性曲线入手,分析了风机产生喘振的主要原因,采用可变极限流量法消除风机喘振,并在实际工程中实施应用,结果表明有良好的节能与防喘振控制效果.     

离心式压缩机智能控制系统的研制

采用交流伺服系统组成了离心式压缩机的智能控制系统.该系统具有独特的压缩机实时工况分析与决策,可按照需要分别实现等压控制,等质量流量控制,并具有自动防喘振功能及运行参数的网络传输与远程监控功能.     

防爆环境下高效液压气动装置主传动与控制策略研究

针对防爆环境下高效液压气动装置的主传动和控制策略进行阐述,设计出螺杆式空压机储气罐的主传动装置、空气压力控制系统和压缩机温度控制系统,从而实现无电状态下的控制方法.     

采用自适应观测器的离心压缩机喘振的转矩控制

提出了一种自适应的观测器,对实际中较难测量的质量流量进行估计,并以此作为反馈对离心压缩机的喘振现象进行控制。由于采用转矩作为控制量,因而不需要额外的作动机构,利用Lypunov方法证明了观测器和控制器是全局稳定的。仿真结果表明了模型和控制策略的有效性。     

Steady air injection flow control for increasing the surge margin of radial flow compressor

Steady air injection upstream of the leading edge was used to increase the surge margin of a centrifugal compressor.To reveal the mechanism,steady numerical simulations were performed on a high pressure ratio centrifugal compressor rotor operated with a rotor tip speed of 586 m/s.Eight different injection yaw angle with four different injection mass flow was performed to determine the configuration that provide the best results for the compression system studied in this work.The injection angle,α,was fifteen degree and the injectors were placed at short distance(ten percent of the inlet tip radius upstream of the compressor face) to achieve maximum control over the leading edge flow by varying individual injection parameters.The results show that at design speed(n=50 000 r/min) with injection flow rate more than 2% of the main flow rate and yaw angle between 20° and 30°,the mass flow rate at stall decreases for approximately 8%.But with higher injection rate,other compressor parameters were affected such as compressor efficiency and compressor total pressure ratio.     

大型高压离心压缩机稳定运行监控系统研究

研究了基于现场总线技术的压缩机防喘振控制系统.该防喘振控系统选出了一种适合应用的现场总线—CAN总线,选择DeviceNet为通讯规范,将压缩机防喘振控制系统分为现场采集节点和上位机控制系统两部分.详细论述了节点的功能模块组成,各模块的工作原理、硬件设计、软件设计及它们的实现方法.经现场调试证明,本系统可防止喘振现象的发生;根据工况变化,可自动进行压缩机回流量调节;在保证不发生喘振的前提下,使回流量降至最低值.     

Experimental investigation of transient characteristics of mild surge and diffuser rotating stall in a centrifugal compressor with vaned diffuser

The centrifugal compressor is widely used for gas compression in various industrial fields such as aero-engine, gas turbine and turbocharger. However, the stable operating range is usually restricted by the occurrence of flow instability such as stall and surge. The paper experimentally examines the developing process of surge and stall occurring in a centrifugal compressor to advance the understanding on flow mechanism of flow instability. It is found that three types of pressure fluctuation can be observed at low flowrate region. At the critical point, the local stall firstly occurs in some specific diffuser passages and the enlarged local diffuser stall eventually induces the mild surge of compression system indicated by the sinusoidal pressure fluctuation. At lower mass flow rate, the diffuser stall cell begins to circumferentially propagate along the impeller rotating direction at 11% of rotor speed with the existence of mild surge. In comparative analysis of IGV pre-swirl angle on the occurrence of mild surge, the mild surge still occurs at the operating condition when the slope of the characteristic map of test stage is still obviously negative, in which the compression system is supposed to be stable in previous study. And a new suggested criterion for the prediction of mild surge is demonstrated that the occurrence of mild surge depends on the destabilization effect of downstream components about diffuser and volute. Combined with the experimental data, the streamwise distribution characteristic of diffuser stall can be used to develop the simplified model of lumped parameters for the analysis on the generation mechanism of the diffuser rotating stall. The quantitative investigation on the relation between the pressure-rise characteristic of subcomponents and the occurrence of mild surge and diffuser rotating stall not only advances the prediction of stability limit but also lays the theoretic foundation for controlling these unsteady behaviors to improve the operating range.     

Influence of volute distortion on the performance of turbocharger centrifugal compressor with vane diffuser

As the geometry of the volute of turbocharger compressor is non-axisymmetric,it causes a distortion at the outlet of the diffuser and influences the upstream components.A distortion model in which a pressure distortion was applied as outlet boundary condition was established to simulate the distortion induced by the volute.It turned out to be sufficient to impose a circumferentially asymmetric pressure distribution at the outlet of the diffuser to replace the volute.Based on the distortion model which was verified,the influence of the amplitude of the distortion on the performance of centrifugal compressor was studied in detail.The results show that the distortion severely harms aerodynamic stability of the investigated compressor.The larger the amplitude of the distortion,the worse the performance of the compressor.The distortion induced by asymmetric volute propagates to upstream components and causes local flow separation at part of diffuser and impeller,and then causes the compressor surge.When the amplitude of the volute distortion is 10%,the stable flow range of the centrifugal compressor decreases to near zero.To authors’knowledge,the relationship between the compressor performance and distortion amplitude is first obtained quantitatively,which provides evidence to improve the performance of turbocharger compressor by decreasing the distortion induced by asymmetric volute.     

二级增压系统中高压级压气机性能研究

为使高低两级压气机达到优化匹配,提高整个二级增压系统的效率,在二级增压系统试验台架上对高压级压气机的性能进行了研究。通过在增压系统中,使新鲜空气首先通过低压级压气机进行预压缩,提高其温度和压力,从而得到高压级压气机的高温高压进口条件。在两级压气机之间设置中冷器,使每一条等转速曲线,高压级压气机进口温度保持不变。试验结果表明,由于进口温度提高,压气机折合转速与实际转速相差较大,为达到预定压比,必须进一步提高压气机转速;进口压力大幅度提高是造成高压级压气机折合流量偏小的主要原因;为避免高压级压气机发生喘振,应控制高压级压气机的进口压力。     

基于轴向力的离心压缩机级密封的状态预测方法

本文讨论离心压缩机级密封状态的评估问题。根据离心压缩机转子所承受的、可实时监测的轴向力与级密封间隙的关系,提出了基于轴向力的离心压缩机级密封状态的预测方法。在分析叶轮两侧缝隙内泄漏气体流动的基础上,采用计算流体动力学方法对其进行仿真,得到轮盘及轮盖上的压力分布,由此计算出轴向力。把不同级密封间隙值及对应的轴向力作为输出、输入向量,对BP神经网络进行训练,以获得在线状态评估模型。测试结果表明,该模型对离心压缩机级密封的状态预测方法是有效的。     

Effects of blade bowing on the performance of a high pressure-ratio turbocharger centrifugal compressor with self-recirculation casing treatment

The effects of blade bowing on the performance of a high pressure-ratio turbocharger centrifugal compressor were studied by experiments and numerical simulation.The results showed that the negative bowing was capable of increasing the choke mass rate and the efficiency but decreased the surge mass flow rate,while the positive bowing had the opposite effects.When coupling with the self-recirculation casing treatment,the surge mass flow rate of the compressor with negative bowing blade was almost identical with that of the prototype,while the choke mass flow rate was still larger,and the total effect contributed to an increase of the stable flow range by 5.85%at design speed.Besides,the flow mechanism of the coupling effects of blade bowing and self-recirculation casing treatment was discussed.     

Performance analysis and improvement of a high flow coefficient centrifugal compressor

Very high flow coefficient centrifugal compressor stages are mostly applied as the first stages of multistage compressors.The performance of this type of stages is critical to the entire centrifugal compressors,but surprisingly little related information is available in the open literature.A centrifugal compressor with high inlet flow coefficient of 0.2,presenting a narrow operating range and unstable running situation even at design speed during the test,is investigated here.To reveal flow details in this centrifugal compressor,numerical simulations have been carried out and indicate that excessive impeller flow diffusion results in the poor performance of this centrifugal compressor.With the same inlet flow coefficient,six redesign cases coming from an in-house one-dimensional analysis program are proposed together with impeller trimming and equal flow area design method for corresponding vaneless diffuser.Performance comparison among these redesign centrifugal compressors is presented and the most suitable one is recommended for test in the future.In addition,three redesign cases with lower inlet flow coefficient developed by means of flow trimming are shown in the end to satisfy potential application areas.Finally,the results in this study can provide valuable reference information for multistage centrifugal compressor design.     

利用轴向力预测离心压缩机的级密封状态

根据离心压缩机转子所承受的、可实时监测的轴向力与级密封间隙的关系,提出了基于轴向力的离心压缩机级密封状态的预测方法.在分析叶轮两侧缝隙内泄漏气体流动的基础上,采用计算流体动力学方法对其进行仿真,得到轮盘及轮盖上的压力分布,由此计算出轴向力.把不同级密封间隙值及对应的轴向力作为输出、输入向量,对BP神经网络进行训练,以获得在线状态预测模型.测试结果表明,该模型对离心压缩机级密封的状态预测是有效的.