塔底废水泵叶轮腐蚀失效分析

某天然气处理厂甲醇再生回收塔塔底建有一台废水转液泵，为离心泵。在运行一段时间后发现叶轮腐蚀严重，为了保证系统的安全运行，特对腐蚀原因进行了研究和分析。最终得出结论，生产水成分复杂，腐蚀性较强，其中的溶解氧和铁细菌是导致离心泵泵体及叶轮发生腐蚀的主要原因，叶轮的强度低于或处于标准要求的下限，且硬度较低，导致叶轮抗汽蚀能力下降。     

SVK型压缩机轴承温度高原因分析及处理

空分装置SVK型氮气压缩机是空分系统核心机组,整体结构是H型布局,采用三级压缩,低速齿轮转子带动一、二级叶轮,高速转子带动三级叶轮。在运行中出现三级轴承温度高的情况,并且经常无规律变化,时刻都有联锁停机的风险,影响整个空分系统安全稳定运行。通过对机组运行数据、装配数据的分析,提出了增加油量等处理措施,轴承温度波动问题得到了有效的解决。     

大型循环水泵的节能改造

某公司循环水系统6台大型双吸泵存在过度扬程现象,且在偏离设计工况点的大流量区运行,效率低下,存在很大的能源浪费。本文通过对几种解决方案的综合对比分析,在不改变水泵其它零部件的前提下,采用高效叶轮设计方法对叶轮进行重新设计与加工,将水泵的额定流量从2898 m~3/h提高至3200 m~3/h,改造后的单台水泵机组每年节约电耗约540万kW·h,节能效果显著。     

多级离心压缩机叶轮逆向工程气动设计

本文提出了一种离心压缩机备件转子新的制造方法,即多级离心压缩机叶轮逆向工程气动设计。以某多级离心压缩机机组为研究对象,对叶轮进行逆向工程气动设计。首先,分析机组数据表参数,反求各级叶轮气动性能,并以此作为设计目标;然后,在保证所有定子组件及子午结构不变前提下,进行叶轮设计,并对设计方案的气动性能和力学强度进行校核;最后,预测离心压缩机组的气动性能曲线。计算结果表明,设计点的气动性能、稳定运行工况范围以及强度性能均满足原压缩机机组的要求。     

单级悬臂压缩机组可倾瓦轴承超温问题分析及处理

针对某单级悬臂压缩机组在试车过程中高速轴叶轮端可倾瓦轴承出现的超温问题,系统分析了原因并给出了解决方案。通过研究该机组试车时的运行情况,总结了机组高速轴叶轮端可倾瓦轴承超温问题的现象,系统分析了超温问题的原因,给出了可行的处理方案。运行结果表明:采用该处理方案可以有效的解决单级悬臂机组的超温问题,对其它领域应用的可倾瓦轴承超温问题有借鉴意义。     

核电主给水泵叶轮不同加工成形状态对比试验

通过对采用不同加工成形方法制作的核电主给水泵用马氏体不锈钢叶轮进行热处理试验、金相组织分析、力学性能测试、全面腐蚀试验、表面粗糙度测定及材料弹性模量等对比试验分析,阐述并论证了核电主给水泵用锻造成形叶轮在使用性能、寿命以及对整机运行可靠性等方面均优于铸造成形叶轮;锻造叶轮能充分满足核电主给水泵设计要求及整机功能需要。     

离心式压缩机叶轮裂纹分析及修复措施

针对某大型空压机叶轮根部产生裂纹问题,通过有限元方法(FEM)对叶轮内部应力分布进行了数值计算,采用电镜扫描和能谱分析方法对叶轮裂纹失效机理进行了实验分析,发现叶轮裂纹为典型的应力腐蚀沿晶开裂,并对该叶轮的修复技术进行了研究探讨.     

新型高效CO2压缩机改造设计和研制

对原CO2压缩机组存在的问题进行了调查和分析,并采用实际运行分析和理论计算相结合的方法,重新设计了5#CO2机,合5#CO2机组的运行效率与旧机组相比提高了40%以上,同时,机组清理周期延长一倍,稳定了系统生产.     

岱海电厂凝结水泵去叶轮改造分析

介绍了岱海电厂二期机组凝结水泵去叶轮改造的基本情况,并根据凝结水泵去叶轮改造前后运行参数的对比,计算出了改造后的具体节能效果。同时根据运行中已发现的问题,分析并总结了凝结水泵改造后对各相关系统及设备安全的影响,提出了相应的预防措施,并取得了一定的效果。     

淮安抽水二站更新改造分析研究

淮安抽水二站因运行已久,水工建筑物混凝土破损,金属结构部分锈蚀严重,主要电气设备绝缘性能差,机组效率下降,存在严重安全隐患。针对淮安二站的现状,从水工建筑物、主机、辅机、电气设备四个方面分析现存的问题,提出相应的改造措施。着重对主机部分的叶轮、叶片、导叶的汽蚀状况进行分析,并根据运行至今的水头与装置效率曲线分析机组效率下降问题,这对类似泵站的安全检测与分析具有参考借鉴意义。     

Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling

Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.     

Review on Stress Corrosion and Corrosion Fatigue Failure of Centrifugal Compressor Impeller

Corrosion failure,especially stress corrosion cracking and corrosion fatigue,is the main cause of centrifugal compressor impeller failure.And it is concealed and destructive.This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments,and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution(AD),the hydrogen-induced cracking(HIC),and the combined AD and HIC mechanisms.The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking.The effects of stress ratio,loading frequency,and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized.The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments,which contain sulfide,chlorides,and carbonate,are analyzed.The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments.The current research methods for centrifugal compressor impeller corrosion failure are analyzed.Physical analysis,numerical simulation,and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.     

C150M×3型空压机运行分析及改进措施

简述了C150M×3型空压机的结构和工作原理,详细分析了机组在运行过程中出现的振动高、级间换热器结垢和扩压器腐蚀等问题的原因,提出相应的改进措施。     

中东含硫原油炼制设备的腐蚀分析及防护

通过对某炼油厂常减压蒸馏装置在生产中出现的腐蚀情况的分析,探讨引起腐蚀的原因,并提出一些防腐措施,以供工程参考。     

用组合单元法分析轴流通风机叶轮的耦合振动特性

采用组合单元法分析了轴流通风机叶轮的振动特性。首先，建立轴流通风机叶轮的组合单元动力学模型，再在此基础上计算了叶轮的固有振动频率和振型。据此，指出了采用组合单元法分析叶轮振动是切实可行的好方法。     

延迟焦化辐射进料泵节能改造

对某炼厂延迟焦化辐射进料泵的运行情况进行了分析,论证了切割叶轮、拆去个别叶轮、变频调速3种改造方案的优劣,发现实施拆除个别叶轮的方案较好,并按此法对某炼厂延迟焦化辐射进料泵实施改造,改造后泵性能完全可以满足生产要求,电机运行电流降低了10A,经济效益明显。最后提出了拆去个别叶轮与叶轮切割组合实施的方案最具经济性。     

基于Fluent的油井井下发电机叶轮的仿真设计

叶轮是叶片式机械中直接进行能量转换的部件,是叶片式流体机械的心脏,合理的叶片形状对叶轮的水力性能、空蚀性能、工作稳定性能及适应井下工作状况的能力有着直接的影响.根据石油井下特殊情况,引入了发电叶轮的设计模型,生成3种不同叶形的叶轮,并利用Fluent软件对3种叶轮进行对比分析,获得水力性能最优的叶轮.     

多级离心泵叶轮口环磨损监测方法研究

采用计算流体动力学理论对多级离心泵整机流场进行了建模,分析了多级离心泵口环间隙对整机流场的影响,得到了多级离心泵效率随口环磨损变化的曲线,引入了轴向振动指标,将效率与轴向振动相结合,提出一种口环磨损量实时监测评估方法。建立了多级离心泵实验台,将实验结果与模拟结果相对比,验证了所提出方法的可行性。通过实验分析了口环磨损故障与叶轮腐蚀以及堵塞故障的特点,排除了叶轮腐蚀及堵塞对口环磨损实时监测的影响,完善了所提出方法。     

污垢对换热器壳程压降的影响分析

随着污垢在传热表面上积聚,换热器流道表面的粗糙度增加,摩擦系数增大,并且流体的流通截面积减小,引起流体流速增加,压力降增大。建立了换热器壳程单元流道模型,对计及污垢影响下的壳程压降进行了试探性的分析及讨论,研究并确定了换热器污垢影响最小化因素,为设计、操作换热器时降低污垢带来的影响提供理论依据。     

Failure analysis of melt urea pump impeller

Abstract

A melt urea pump is out of work after only 6 days in service. The failure of the melt urea pump impeller is analysed using different methods including chemical composition analysis, metallographic observation, SEM and energy dispersive spectroscopy analyses, etc. The results show that the material of the impeller is not the reported AISI 321 stainless steel but AISI 316 stainless steel. There are many honeycombed holes on its impeller, which is the typical feature of cavitation damage. Therefore, the main failure reason of the impeller is the cavitation erosion, and the electrochemical corrosion of the medium also accelerated the failure of the impeller. The failure of the impeller is not related with the as casted defects of the material because no obvious as casted defects are found in the material.