蒸汽发生器堵头设计与堵管研究

堵管是核电站蒸汽发生器传热管破损的主要维修方法。调研并设计了堵头的结构，利用有限元软件ANSYS仿真分析了堵管过程，进行了堵管试验，并对被堵的传热管进行了密封性和力学性能检验。试验结果表明，堵头的结构设计合理，堵管通过了RCC—M规定的性能测试。     

核电站蒸汽发生器传热管机械堵管工艺评定

堵管是核电站蒸汽发生器传热管破损的主要维修方法.根据ASME B&PVC规范,介绍了核电站蒸汽发生器机械堵管工艺评定的相关要求,如水压试验、热态循环试验等,并举例介绍了具体的评定过程,供核电站蒸汽发生器堵管工具设计、制造及维修单位参考.     

压水堆核电厂蒸汽发生器传热管的降质问题

核电厂蒸汽发生器传热管的降质将影响到核电厂一回路边界的完整性。通过对蒸汽发生器传热管的降质模式进行分析，并对在役传热管无损检测技术应用以及寿命预测的介绍，从而针对产生的传热管降质的原因，采取相应的防护措施，确保蒸汽发生器传热管的安全运行。     

核电站蒸汽发生器传热管涡流自动检测系统研制

设计了蒸汽发生器传热管涡流自动检测系统,从探头定位系统、探头扫查系统、集成传输系统和相关软件等方面,分析了系统设计。将系统用于对核电站蒸汽发生器传热管进行涡流检查,能够及早发现传热管上存在的缺陷,为进一步采取的维修措施提供准确的参考依据,并成功应用于各核电厂的役前和在役检测。     

核电厂蒸汽发生器运行维护的措施

蒸汽发生器是核电站的重要设备之一,通过对蒸汽发生器运行性能、结构特性降解表现形式以及影响因素的分析,结合国内外核电领域的研究成果和运行经验,描述了在役蒸汽发生器在功率运行期间水化学管理,换料大修停用期间二次侧泥渣冲洗、内部构件检查、保养等方面需采取的维护措施;进行蒸汽发生器结构完整性评估,以降低蒸汽发生器传热管破损风险,保障蒸汽发生器结构的完整性。     

蒸汽发生器单根传热管振动特性试验和分析

掌握蒸汽发生器单根传热管的振动特性是开展管束区流致振动分析评价的基础,针对某型蒸汽发生器,选取弯管半径最大的局部单根传热管,通过试验方法研究传热管管内外附加水质量、管内压力、防振条支撑间隙以及防振条支撑位置传热管正常磨损等因素对振动特性的影响,并通过试验结果与分析结果进行对比,论证设计间隙情况下分析模型和边界条件的合理性。研究结果表明,附加水质量会造成传热管频率降低,管内压力和传热管正常磨损不会影响传热管振动特性,连续两个防振条支撑点间隙大于0.13 mm会造成传热管弯管区开始出现支撑失效,处于设计名义间隙内的传热管在防振条位置的边界条件可以近似简化为简支。     

核电蒸汽发生器传热管与管板胀接性能分析

蒸汽发生器中传热管与管板接头的泄漏是威胁核安全的主要原因。通过有限元软件ANSYS Workbench模拟了传热管与管板胀接与拉脱的过程,得到了残余接触压力的分布规律以及胀接压力与残余接触压力、拉脱力、壁厚减薄率的关系。并针对传热管的尺寸公差,研究了传热管直径与壁厚对于胀接性能的影响。结果表明:在胀接工艺中,胀接压力选取在260 MPa比较合适,能使核电蒸发器中全部10025根传热管达到较好的胀接质量,同时保证了生产效率和经济性。     

蒸汽发生器换热管与支承板的材料及结构

对核电蒸汽发生器换热管与管子支承板材料、结构及两者匹配合理性进行分析,指出当前蒸汽发生器设计过程中换热管的优选材料及支承板结构。     

蒸汽发生器一次侧受损处理原则的讨论

蒸汽发生器一次侧异物事件可造成蒸汽发生器一次侧表面甚至传热管损伤,可对蒸汽发生器完整性产生危害。简述蒸汽发生器异物一次侧的设计及功能要求,对一次侧受损所产生的影响进行分析,并对修复原则进行讨论。认为异物导致的表面硬化会影响材料的抗应力腐蚀性能,但裂纹不会对设备的完整性产生影响;管子-管板焊缝承担了部分结构焊缝的功能,有条件时,可进行修复。     

蒸汽发生器传热管流弹失稳计算

蒸汽发生器管束一旦出现流弹失稳现象,可以在很短的时间内破坏传热管的完整性,影响核电站安全。因此,在设计蒸汽发生器时要预测与防止传热管流弹失稳现象。通过有限元软件ANSYS的梁单元建立传热管模型,进行模态分析并提取相关结果;然后将模态分析的结果代入MATLAB计算传热管流弹不稳定率并和专用软件进行对比。该方法计算结果与专用软件吻合,且分析表明套筒开口区与弯管区流速对流弹不稳定率影响较大;管子高频时不易发生流弹失稳现象。     

Plugging criteria for thinned high-pressure feedwater heater tubes considering pressure and thermal loading

When heat exchanger tubes have critical thinning which could cause unsafe conditions, it is general practice to plug the tubes so that they are out of service to prevent rupture failure at the thinnest location. Plugging criteria for the high-pressure feedwater heater tubes of fossil power plant were studied. Tubes in the desuperheating zone were considered due to their high internal pressure and the high temperature difference across the tube wall. Theoretical analysis of uniform thinning and eccentric thinning of the tube was conducted to determine the stress conditions at the thinnest location under internal/external pressure and thermal gradient across the tube. The minimum required tube thickness was determined using the maximum shear stress criterion (Tresca theory). Accuracy and effectiveness of the analytic solutions of the stresses were verified by comparing the results obtained with those obtained from finite element analysis. Using finite element analysis, the stresses for eccentric thinning were determined. Thermal loading due to temperature difference across the wall was considered even though the contribution of pressure loading to the stress of the tube was known to be higher than that of the thermal loading. As case studies, the tube plugging criteria of three high pressure feedwater heaters were determined using actual temperature and design pressure industry data. The procedure used in this study can be applied to different pressure and temperature operating conditions, and different tube materials.     

管道封堵气囊结构设计与密封性能研究

为实现石油和天然气管道的快速封堵,设计一款可用于管道快速封堵和导流的机器人以及充气膨胀性的封堵装置。该封堵装置由气囊和导通管组成,气囊充气膨胀后挤压管道的内壁和导通管的外壁,从而构成一个密封区域,使液体不会从管道裂缝中泄漏,而是从中间导通管流过,实现封堵和导流功能。设计4种不同结构的气囊模型,研究其在不同压力下的最大von Mises应力和接触应力分布。结果表明,气囊外部与管壁接触边的倒角为直角,气囊内部为圆形中空结构时,气囊的接触应力最大,接触密封效果最好,同时应力也最小,承压能力最强。     

A newly developed plug in the drawing process for achieving the high accuracy of aluminum rectangular tube

Aluminum rectangular tube is the key component in the field of microwave transmission whose service condition requests strict dimensional accuracy and internal surface quality. To meet these requirements, a newly developed plug featuring a tiny boss club structure in the sizing zone has been proposed in the plug drawing process. The optimal combination of the dimensions in the boss club has been obtained using the method of 3D finite element simulation and orthogonal experimental design. The plastic strain distribution, the contact status between the tube inner surface and the plug, the dimensional accuracy of the formed part, and the forming load have been compared between conditions where the traditional linear-type plug and this new type of plug have been used, respectively. It can be seen clearly that when the plug with a tiny boss club structure is adopted, the contact quality is better and the larger plastic strain exists on the inner surface of the tube, which is very crucial in improving the surface finish of the formed part. Meanwhile, the deviation of wall thickness and the axial length in the formed part is smaller based on the new type of plug. The experiment of the drawing process with two types of plugs has been carried out in which the surface finish of the inner tube surface and the wall thickness have been measured and compared. Experiment result shows that the dimensional accuracy and inner surface quality meet the requirements of the service condition when the plug with a tiny boss club structure is employed.     

Contact pressure distribution in circular tube expansion using a conical plug

The technique of evaluating contact pressure distributions along a plug metal interface by measuring the deformations in terms of plug surface strains using electrical resistance strain gauges has been explored. To relate the unknown pressure distributions to the strain gauge readings, a finite element model of a plug was used assuming that the normal and shear pressures can be represented as a linear combination of generalized distributions, which have the form of polynomials up to the fourth order.This technique has been suitably applied to a thin brass tube expanding process for a single expansion ratio, and a single conical hollow plug with and without lubricant. To ensure good accuracy in the results, particular care was given to technological plug design and the choice of a number of appropriate strain gauged points on the inside surface of the plug.The more adequate polynomial representations of the normal and shear contact pressures were found by analyzing the degree of randomness in the distribution of the residuals. A comparison was made between experimental pressure distributions and those predicted by the slab method. Results obtained were compared with those derived from the use of a polynomial curve fitting method, besides assuming an average coefficient of friction at the interface.     

径向双球塞柱塞马达广义椭圆定子曲线导轨的分析与设计

针对常规径向液压马达存在定子导轨曲线绘图精度低且过程繁琐、曲线导轨磨损严重的问题,提出了一种采用广义椭圆定子曲线导轨的双球塞结构的液压马达。广义椭圆定子曲线延展性好,在一定程度上可以解决常规径向液压马达定子导轨曲线绘图精度低且过程繁琐的问题;双球塞结构增大了球塞与定子曲线内壁的接触面积,一定程度上可以解决常规径向液压马达导轨磨损严重的问题。当作用次数为5~12,长、短轴比例系数为1.07~1.18时,该类型球塞马达可以获得较为优异的输出性能。     

高压预冷器2205异种钢焊接制造工艺技术探讨

某天然气处理厂的高压预冷器,采用固定薄管板结构,由于管程介质中Cl-含量较高,管箱材质采用2205双相钢复合钢板,管板采用2205双相钢纯材,壳程材质为16MnR(或09MnNiDR)。阐述和分析了管板与管箱、壳程在焊接制造过程中遇到的技术难题和采取的有效措施,从而为双相钢设备的焊接制造提供经验。     

压力容器接管与壳体装焊的质量控制

分析了压力容器接管与壳体组装结构对压力容器安全运行的影响。论述了接管与壳体组装与焊接过程中质量控制的重要性及质量控制要素。最终获得能够满足使用要求的接管与壳体焊接接头。     

A parametric study on residual stresses and forging load in cold radial forging process

In this work, a comprehensive study of radial forging process is presented through 2-D axisymmetric and 3-D finite element simulations while considering internal tube profile. The tube used in this investigation has four internal helical grooves along its length. The material is modeled with the elastic-plastic behavior, and sliding-sticking friction model is utilized to model the die-workpiece and mandrel-workpiece contacts. The numerical results in the 2-D case are compared with available experimental data. Residual stresses in the forged product, stress concentration around the grooves, pressure distribution on the hammers and mandrel and maximum forging load are studied. The effects of process parameters such as workpiece and die geometries, percentage of deformation, and workpiece motions on residual stresses and applied pressures on the hammers and mandrel are investigated. The results provide a valuable insight into the parameters affecting radially forged products and provide a useful tool for better design of this process.     

液压胀管法在冷凝器上的应用

主要介绍了液压胀管的胀管压力的理论计算和试验情况以及在设备上的实际应用。