影响凝汽器钛复合管板高速钻孔加工的关键因素

某型凝汽器设备利用海水作为冷却介质,凝汽器管板采用了爆炸复合的钛复合板。对钛复合管板进行高速钻孔加工,是凝汽器制造中的难题。通过大量的工艺试验及数据分析,钛复合管板的平面度、管板加工时的装夹、选择刀具及切削参数等因素,都会影响高速钻孔的加工质量。选择适当的加工工艺,是提高钛管板钻孔质量的关键。     

汽水分离再热器新蒸汽换热器管板组件制造工艺研究

简要介绍岭澳核电站MSR新蒸汽换热器管板组件的制造工艺,着重介绍了设计结构、管板镍基合金堆焊、管板深孔加工以及管板的表面处理工艺。     

高压加热器管子管板自动脉冲氩弧焊的应用

阐述了汽轮机辅机中高压加热器U型换热管与管板的结构形式及焊接装配定位方法,对自动脉冲氩弧焊的焊接工艺过程与焊接过程中的控制措施进行了分析.该工艺应用后,保证了高压加热器换热管与管板管端焊缝质量,提升了高压加热器换热效率.     

核级热交换器管子管板胀接及质量控制

制造换热器管束时,管子管板的液压胀接是常用的加工工艺。在液压胀接过程中,主要经历了管子管壁屈服、管子管板间隙消失、加压到最大胀接力和卸压等过程,胀接质量主要受胀接力、间隙、清洁度和胀接长度等因素的影响。以CPR1000项目余热排出热交换器的胀接工艺为例,对管子管板液压胀接工艺评定和影响因素进行了分析,总结了胀接前及胀接过程中的质量控制要点,为核电换热器设备的质量控制提供参考。     

铁素体不锈钢管子管板焊接工艺研究

为了提高高压加热器管束的使用寿命和可靠性,高压加热器的管子管板接头中采用铁素体不锈钢传热管并且采用平角焊缝,这一焊接工艺变化对管子管板焊接提出了新的要求,因此,通过一系列特定的试验,确定铁素体不锈钢管子管板最佳的焊接工艺方案和工艺参数。     

凝汽器管板焊接工艺及变形控制

秦山核电二期扩建工程650 MW机组凝汽器采用了2种管板结构。由于管板焊缝较长,最长达4 m多,对焊接质量提出了较高的要求。介绍了焊接要点,阐述了管板焊接工艺,探讨了控制管板焊接变形的各项技术措施和方法,有效地解决了管板拼装焊接变形问题。     

多种胀管方法在生产中应用的特点分析

换热器管子与管板的连接,常需采用胀接工艺,管子管板的胀接质量直接影响换热器的密封性能。在换热器或压力容器的制造中,主要的胀管方式有机械胀管、爆炸胀管、液压胀管和橡胶胀管。经比较,提出了胀接形式的选择原则,并利用胀管实例,说明了胀接工艺的应用特点。     

核电小口径换热管与管板的焊接技术

核电系统中有很多核级热交换器,热交换器管子管板的焊接质量,关系到核电机组的安全运行。分析了换热器管子管板的结构特点,利用光感定位的方法,采用小口径管子管板专用的焊接设备,解决了焊接工艺中的难点,利用小口径管子管板的填丝自动焊技术,提高了管子管板接头的焊接质量,同时,还降低了焊工的劳动强度。     

镍基合金堆焊和管子管板焊接工艺的研究

为研制某型热交换器,进行了管板堆焊和管子管板的焊接试验。该型热交换器的换热管采用了690镍基合金管,管板材料为SA508Gr.3CL2,堆焊材料为690镍基合金。堆焊前,先通过试验确定焊接工艺参数,再正式堆焊试件。管板堆焊采用带极埋弧焊,管子管板焊接采用了自动钨极氩弧焊。经焊接试验,确定了各项焊接参数,并对焊后试件进行了无损检测、氦检漏(管子管板)和各项理化试验,试验结果均符合试验大纲的要求。     

超厚管板中的管子液压胀接技术探讨

高压加热器是电站设备中的重要辅机,管子管板的胀接在高压加热器制造中是较为关键的工序,随着新建发电机组功率的增大,使高压加热器管板的外形尺寸和厚度也相应增大。为此,需对大直径与超厚管板的高压加热器的管子管板胀接进行不同胀接工艺形式的比较,从而优选管子管板胀接的工艺方法。探讨不同胀接长度的单位拉脱力以确定合适的试样胀接长度,并对胀接参数做了定量的分析评定。     

锅炉末级过热器爆管原因分析及措施

通过宏观形貌、成分分析、低倍观察、金相组织、硬度检验、室温拉伸和冲击试验等对某电厂2×362MW机组锅炉末级过热器爆管原因进行了分析。结果表明,爆管I(材质T22)断裂与焊道设计不合理、母材管金相组织及力学性能不合格有关;爆管II(材质T91)断裂系焊接工艺执行不当,焊缝熔合线处存在夹渣和焊缝硬度偏高所致。对此提出了顶棚穿墙管与密封板的角焊缝应尽量避开密封板对接焊缝,改进密封板与管的焊接结构,减小定位块厚度等建议。     

钢管角钢组合塔变坡节点承载力研究

为研究钢管角钢组合塔变坡节点特性,对2个相同尺寸、不同加载方式的变坡节点进行静力足尺试验,对受力性能、承载力和破坏模式的分析研究表明,节点破坏模式均为受压端节点板平面外失稳,说明节点板是薄弱区域。采用有限元软件ABAQUS建立三维实体模型,对影响变坡节点承载力的主要因素进行参数分析,结果表明,在一定范围内,节点承载力随节点板厚度的增大而提高,节点板厚度每增加2 mm,承载力提高5%~9%,当厚度增加到一定限度,承载力提高30%左右,节点板得到充分利用。     

沙角A电厂5号锅炉再热器管泄漏原因分析及处理

针对沙角A电厂5号炉在每次机组大、小修后进行水压试验期间，末叛再热器管和屏式再热器管在与顶棚密封板的焊接焊缝处都会发生泄漏的问题，经多年的运行观察及对泄漏管子进行分析，认为顶棚密封的刚性结构、再热器管子材料金属机械性能相对较差，再热器管子与顶棚密封的焊接质量较差等是造成再热器管发生泄漏的主要原因，在该炉大修期间采用改装定位密封板、加装套管、更换再热嚣管材等相应措施对再热器顶棚密封结构进行了相应改造。改造后未出现泄漏情况，达到了预期的目的。     

大型燃气轮机余热锅炉进口烟道速度均匀性研究

通过对燃气轮机出口与锅炉本体进口之间过渡烟道的数值模拟，得出不同仰角上面板烟道出口的速度分布。根据出口速度均匀性，确定了最佳仰角。此外，对非均速进口气流流经锅炉管束时的流场也进行了数值模拟，结果表明：大约经过4～5排管子，主气流速度即趋于均匀。在管箱顶部和底部，存在局部高速区，易造成管子磨损。这些结论已用于燃机余热锅炉的设计，并取得良好效果，使烟气均匀性问题得到解决。     

300MW机组锅炉“四管”泄漏检修分析

对300MW机组锅炉受热面存在的长期或短期过热、材料性能劣化及异种钢焊缝失效,穿墙管密封、磨损腐蚀等问题分别进行了分析,提出了加强锅炉部件内部构件检查防止异物造成管孔堵塞,避免炉墙密封护板与受热面管直接焊接,定期清理不锈钢弯头部位积灰等预防及检修措施。     

Investigation of Heat Transfer Surfaces for Space Power Systems

Heat exchangers used in the composition of large-capacity energy conversion systems for space applications must be able to operate at high temperatures (above 1000 K) and at high (several MPa) values of pressure difference between the “hot” and “cold” heat carrier/coolant channels. This is why especially demanding strength and stiffness requirements are posed to the heat-transfer matrix of these devices, a circumstance that precludes almost completely the use of well-known compact and light plate-and-fin devices with 50–100-μm-thick foil fins. The article presents the results from experimental investigations into the thermal and hydraulic characteristics of alternative versions of heat-transfer elements involving the use of different heat transfer enhancement methods. Experimental investigations of heat transfer and hydrodynamics were carried out for three types of heat-transfer surfaces: a tubular one composed of small-diameter (3 mm) thin-walled tubes deformed over the cross-section perimeter and length (twisted tubes), a plate one finned with pins having a diamond-shaped cross section (2 × 2 mm in cross section and 4 mm in height), and a plate one composed of thin-walled 0.2-mm-thick plates with the surface formed by oppositely directed truncated cones with saddle-like bridges (a biconvex stamped plate). After processing and analyzing the experimental data obtained for these heat-transfer surfaces, dimensionless dependences for the Nusselt number and the pressure-drop coefficient on the Reynolds number were constructed. The dimensionless formulas obtained for twisted tubes and for the pin-finned surface are compared with the well-known correlations. It is shown that the use of twisted tubes instead of round ones results in improving the heat transfer intensity by more than 20% with the hydrodynamic indicators worsened by 50%. The use of the pin-finned plate surface improves the heat transfer intensity by more than a factor of two as compared with using a staggered tube bundle.     

Analysis of thermal stresses in horizontal delivery water heaters

Analysis of thermal stresses in tubes and a compensator, taking into account water heating in each heater bunch and temperature at which its mounting is implemented, and of stresses on pressure is presented. The 3D-model of the horizontal delivery water heater of PSG-4900-0.3-1.14 type is used. The tube plate is represented as the 3D-body with 6863 holes with offset center of the perforated area, the steam space shell is represented as a cylindrical casing, the bottoms of water chambers are considered as elliptical casings, the four-lens compensator is represented in the form of toroidal casings, and the tubes are considered as beams operating in tensile-compression and bending in two planes. Calculations were carried out for different temperatures of superheated steam and a steam space shell, respectively, as well as designs with compensator and without it. Various temperature values of the tubes on the passes were calculated and set. The studies were carried out taking into account nonaxis-symmetrical spacing the tube plate and compensator deformation. The calculation results of tensile-compression stresses in the tubes are presented. Furthermore, the central tubes experience compressive stresses, whose maximal values take place on the border between the tubes of the fourth and of the first passes. For its decrease, it is recommended to increase the distance between the tubes of these passes. The tension stresses in the peripheral tubes are the maximal stresses. To reduce the stresses and, therefore, increase service life of the delivery water heater at using wet or superheated (not more than by 30–50°C) steam in it (the larger value refers to the brass tubes and the water pressure of 1.6–2.5 MPa), it is necessary to recommend the noncompensatory design at using the steam superheated by more than 30–50°C (at Ural Turbine Works, it is the turbines of T-250/300-23.5 and T-113/145-12.4 types with intermediate superheating) and to recommend the installation of the compensator operating only at compression.     

加热器挡水板结构可靠性分析

加热器是发电厂常见的换热设备,加热器壳体内尾部的挡水板对于缓冲较高流速的疏水冲刷,并使疏水经过缓冲平稳地注入具有重要作用。由于来自管道的疏水流速较高、冲击力较大,且在特定的激振频率下,会使挡水板的振幅增大,产生应力变化。为确定挡板的受力,应对挡水板结构进行应力和疲劳分析,通过对流体冲击载荷的计算,才能确定牢固且合理的挡板结构。     

高温过热器T91、T22管爆管分析

某电厂锅炉高温过热器T91、T22管在运行2万h后多次发生爆管，通过对原始管、运行管、爆管的组织和性能检测表明，爆管是由于T22管长时处于超温运行，在蒸汽侧产生大量氧化层，而氧化层在起停时剥落并沉积在下弯头附近，从而使管内流量降低，管壁金属短时过热所致。     

利用超声导波检测不锈钢波纹管缺陷

分析得出不锈钢波纹管中超声导波的近似频散方程,利用disperse软件对方程进行数值求解,设计出满足不锈钢波纹管超声导波检测的电磁声(EMAT)换能器及压电换能器,并选择L(0,2)模态超声导波对不锈钢波纹管试样进行检测,结果表明超声导波可以检测不锈钢波纹管的横向裂纹缺陷,而对通孔缺陷较难识别。