超临界压力汽轮机固体颗粒侵蚀的表面硬化处理技术

简要介绍汽轮机的固体颗粒侵蚀及其对机组安全性和经济性的危害，介绍国外为预防汽轮机通流部分的某些喷嘴和动叶固体颗粒侵蚀所采用的各种表面硬化处理技术，包括等离子喷涂和扩散渗层的现场运行经验，供我国发展高性能大容量超临界压力汽轮机及亚临界压力机组受到固体颗粒侵蚀损伤恢复其性能时参考。     

基于SPE的660 MW超临界汽轮机阀控方案数值模拟研究

超临界汽轮机更为突出的固体颗粒侵蚀问题,已成为限制其运行灵活性的障碍。在汽轮发电机组深度调峰和频繁调峰运行模式下,优化阀控方案是减少固体颗粒侵蚀对汽轮机的危害的有效途径。论文以某660 MW超临界汽轮机为研究对象,建立调节级固体颗粒侵蚀模型,对机组在滑压运行和定压运行两种方式下、对应不同工况下,固体颗粒对汽轮机调节级动叶的侵蚀情况进行了数值模拟。通过数值模拟,确定了该型超临界汽轮机调节级固体颗粒侵蚀的主要发生部位,得到了机组分别在定压和滑压运行时,调节级固体颗粒侵蚀密度随负荷变化的规律。通过对模拟结果的分析,提出了降低调节级动叶固体颗粒侵蚀的阀控方案。     

汽轮机进汽固体颗粒捕集技术研究

锅炉氧化皮脱落产生的固体颗粒导致汽轮机叶片破损、阀门磨损、围带铆钉磨损等问题,是超临界、超超临界机组面临的世界性技术难题之一,分析了流场的分布规律,制定了减小固体颗粒对汽轮机喷嘴的冲蚀的措施,达到提高汽轮机寿命的目的。     

超超临界机组蒸汽氧化及固体颗粒侵蚀的综合防治

论述了超超临界机组所面临的突出问题——管道的蒸汽侧氧化及汽轮机叶片的固体颗粒侵蚀(SPE)的产生及对机组的危害,阐述了对SPE进行全方位全过程综合防治的思路:通过锅炉的合理选材,选择塔式炉,配置大容量旁路,采用无调节级汽轮机及合理的进汽结构,对汽轮机叶片作抗冲蚀处理,大幅降低热控保护的误动概率及锅炉强停次数,选择合理的启动和运行方式,慎用减温喷水等,能显著降低锅炉蒸汽侧氧化及氧化皮脱落造成的危害,极大地缓解汽轮机的固体颗粒侵蚀问题。     

362MW汽轮机通流部件的固体颗粒侵蚀分析

通过对362MW进口机组2次大修检查,确认中压缸第1级隔板喷嘴和叶轮遭受固体颗粒侵蚀。分析了隔板和叶轮遭受侵蚀的机理,提出了增强汽轮机通流部件抗侵蚀性的对策。     

1000MW超超临界机组旁路系统工程实践

针对1000 MW超临界机组参数较亚临界机组有很大提高,蒸汽品质要求高,而固体颗粒侵蚀问题更加突出,需要合理地配置旁路系统,才能减轻汽轮机固体颗粒侵蚀的问题,介绍了旁路系统的作用,浙江国华浙能发电有限责任公司二期工程采用了全容量高压旁路和大容量低压旁路的二级旁路配置情况。     

1000MW超超临界机组旁路系统工程实践

针对1000 MW超临界机组参数较亚临界机组有很大提高,蒸汽品质要求高,而固体颗粒侵蚀问题更加突出,需要合理地配置旁路系统,才能减轻汽轮机固体颗粒侵蚀的问题,介绍了旁路系统的作用,浙江国华浙能发电有限责任公司二期工程采用了全容量高压旁路和大容量低压旁路的二级旁路配置情况。     

超(超超)临界机组固体颗粒冲蚀的机理及防治

通过研究超超临界汽轮机固体颗粒侵蚀产生的原因,在制造和运行中采取通流部分优化及喷涂硬化、灵活运用旁路系统等防治措施,可有效降低固体颗粒侵蚀现象的发生。     

汽轮机喷嘴固粒冲蚀模化试验系统及测试方法

基于相似模化理论，并结合数值模拟结果自行设计研制出超超临界、超临界、亚临界3种汽轮机调节级喷嘴蒸汽参数范围的高温高速气固两相流模化试验系统，为研究叶片材料抗固粒冲蚀特性和粒子运动行为规律提供必需的试验条件。为人工生成上述条件下的气固两相流，还研制出一种可调性宽、稳定性良好的固体颗粒加料系统，并对影响加料量脉动因素及其抑制方法进行了专题研究；利用PIV技术并经过多次尝试获得温度在650℃以下、粒子尺寸为2~ 150mm范围、颗粒群速度为150~500m/s的速度矢量场及其运动行为特征；借助快速响应的电子秤并结合取样、调节和控制等多路辅助子系统解决了颗粒加料量的静态和瞬态测量难题；为说明本模化试验系统的主要功能和关键参数的测试方法，文中还给出2个试验研究实例及其典型结果。     

华亭电厂2号汽轮机现状及防范措施

通过对华亭电厂2号汽轮机喷嘴及动叶固体颗粒侵蚀、动叶水蚀、通流部分结垢和积盐现象的分析，初步找到了造成这些现象的原因，并针对具体情况提出了相应的防范措施。     

粒子尺寸和速度对喷嘴叶栅磨蚀特性的影响

应用PIV激光测速仪对某调节级喷嘴叶栅(73A)进行了气固两相流场测量,以研究粒子的尺寸和速度对喷嘴叶栅内粒子运动轨迹及磨蚀特性的影响。实验结果表明:随着固粒尺寸的增加,撞击速度减小,撞击角度和撞击次数增大,叶栅磨蚀大都是大、中粒子造成。粒子的撞击速度与气流速度成正比,气流速度越高,粒子对喷嘴壁面的磨蚀越严重。     

超超临界汽轮机固粒侵蚀和汽流激振分析

超超临界汽轮机的开发设计有很多特殊要求,需解决许多技术问题,其中通流部件的防固粒侵蚀、防止高压转子汽流激振、汽轮机选材问题、转子冷却结构问题、低压进汽容积流量小问题,是关系到超超临界汽轮机组能否安全、稳定、经济运行的关键,为此,重点探讨如何防止通流部件的固粒侵蚀(SPE)和高压转子汽流激振问题。     

超临界压力汽轮机蒸汽激振问题分析及对策

介绍机组蒸汽激振的机理和特征，国外超临界压力机组高压转子低频振动和近年来国内若干大型机组高压转子汽流激振引起的低频振动的分析和现场处理情况，归纳总结引起该类振动的主要因素和我国在发展超临界压力机组中应采取的对策。     

汽轮机通流部分故障诊断模型的研究

本文提出了汽轮机通流部分的故障诊断模型。文中介绍了汽轮机调节闹闹杆断落、喷咀磨损、叶片断阻塞静叶、通流部分结垢、通流部分团体颗粒磨损、汽缸进水、大轴弯曲、动静元件轴向碰摩、蒸汽振荡和真空恶化等10种故障的特征信号、征兆和诊断规则。文中给出了基于可靠性理论的故障诊断模型，以及这10种故障发生概率的计算公式和一些应用实例。     

田湾核电站汽轮机围带间隙超标问题的分析处理

简要描述田湾核电站汽轮机的概况,重点针对汽轮机低压缸转子末级叶片围带间隙超标的缺陷的原因进行了分析,详细介绍了缺陷处理工艺过程,工程实践证明处理措施有效,确保了汽轮机安全稳定运行.     

顺序阀运行方式下600 MW汽轮机瓦温偏高分析

分析了2台西屋600 MW汽轮机在顺序阀运行方式下高压转子径向轴承的瓦温偏高问题,认为这主要与调节级进汽方式有关,而解决调节级部分进汽工况下蒸汽作用力的周向均匀分布,在机组中、低负荷时调节级喷嘴组改为间断性交叉进汽是最为有效的方法.在征询西屋公司改造的可行性并进行调研论证后,进行了现场试验,试验结果表明瓦温下降显著.     

Control valves and cascades for the first stages of turbines with ultrasupercritical steam parameters

This paper considers the problems that will unavoidably be encountered in the creation of new-generation turbines operated at ultrasupercritical initial steam parameters, namely, the development of new control and shutoff valves, the reduction of end energy losses in blade cascades and steam leaks in high-pressure cylinders (HPCs), the elimination of effect produced by regenerative steam bleedoffs on the afterextraction stage, the cooling of a blade cascade, etc. Some possible solutions are given for the two first of the listed problems. The conclusion about the need for the transition to new-generation control valves in the development of new advanced steam turbines with ultrasupercritical initial steam parameters has been made. From the viewpoint of their design, the considered new-generation valves differ from the known contemporary constructions by a shaped axially symmetric confusor channel and perforated zones on the streamlined spool surface and the inlet diffuser saddle part. The analysis of the vibration behavior of new-generation valves has demonstrated a decrease in the dynamic loads acting on their stems. To reduce the end energy losses in nozzle or blade cascades with small aspect ratios, it is proposed to use finned shrouds in the interblade channels. The cross section of fins has a triangular profile, and their height must be comparable with the thickness of the boundary layer in the outlet cross section of a cascade and, provisionally, be smaller than 8% of the cascade chord.     

Ways for Improving Efficiency and Reliability of Steam Turbines at Nuclear Power Stations

The current state and ways for improving the effectiveness of steam turbine units at nuclear power stations (NPS) are examined. The specifics of NPS turbines is described. The comparison of NPS steam turbine performance with the performance of steam turbines at thermal power stations (TPS) demonstrates that power units of NPSs are much poorer in effectiveness due to relatively low steam conditions at the inlet and the presence of wet steam already in the first stages of turbines. A decrease in the relative internal efficiency of NPS turbines results from the enhanced negative effect of wetness in the expansion process: in modern NPS turbines, more than two-thirds of the heat drop is spent in the two-phase region, while less than one fourth in TPS turbines. It is demonstrated that the effectiveness of NPS steam turbine units can be increased drastically in the future only through a considerable rise in the turbine inlet steam conditions. This can be achieved by using a heat carrier at supercritical conditions in the NPS reactor. The dependence of the effectiveness of NPS modern turbines on the turbine inlet steam conditions in the applicable pressure ranges of the saturated steam and vacuum in the condenser, as well as on the turbine exhaust area, is examined. For a 1000 MW turbine, increasing the inlet pressure from 6.0 to 8.0 MPa raises the turbine power and efficiency by 3.5%. At a condensing turbine outlet pressure ranging from 2.5 to 7.5 kPa and a constant velocity downstream of the last stage, the turbine power and efficiency can be increased by 7%. The importance of the exhaust area for the turbine effectiveness is revealed. Alternative designs of the flowpath in a low-pressure cylinder are analyzed. A unique configuration of a steam turbine unit with two-stage moisture separation is proposed. The comparison of high-speed turbines with low-speed ones was performed. It is demonstrated that the efficiency of the examined turbines is nearly the same within the accuracy of design calculations and the test results, and it is slightly higher for low-speed turbines due to lower losses with outlet velocity.