【作者】 徐浩；

【导师】 刘应征； 徐嗣华；

【作者基本信息】 上海交通大学 ， 动力工程（专业学位）， 2017， 硕士

【摘要】 二次再热技术即在常规的朗肯循环中进行两次中间再热,这项技术可以有效的提高整个热循环效率。随着汽轮机技术的发展,新型的常规一次再热机组已经将进汽参数提高到了目前高温材料可承受的极限。因此,为了进一步提高机组效率、降低煤耗,采用二次再热技术是一个重要途径。经过分析,如果将二次再热技术应用在百万等级超超临界机组上,机组的热效率较常规一次再热机组可以提高3.3%~3.6%。采用二次再热技术后,根据热力循环分析,汽轮机设计面临着主蒸汽压力提升、再热蒸汽温度提升、轴系增加一个高温再热缸等难题。特别是对于汽轮机上的高温高压部件的设计带来了极大的挑战,其中阀门作为汽轮机的关键部件之一,需要承受最高的进汽温度和进汽压力,工作环境状况较为恶劣。本文就是已二次再热机组高压阀门为研究对象,对其流场特性、强度性能和疲劳寿命进行计算分析考核。本文首先以CFD流场计算软件CFX为平台,对二次再热机组的高压阀门的内部流场特性进行分析计算,通过在不同流量工况下的全三维蒸汽流场分析,得出高压阀门的流场特征及损失,进而对二次再热机组高压阀门的性能进行分析。其次以有限元软件Abaqus为平台,对二次再热机组的高压阀门进行建模计算分析:对阀门阀体的稳态温度场分析、应力场分析、高温蠕变强度分析,得出该阀门在结构强度上的性能。最后通过对阀门进行热或冷冲击后的结构应力研究,对其在启停及变负荷工况时的寿命进行分析,得出了在不同工况下的寿命损耗,为后续控制机组启动和停机的现场操作提供了依据。通过本文的研究,可以确保二次再热机组高压阀门的成功研发,进而为二次再热机组的成功开发奠定良好的基础,并对同类型高温部件的分析研究方法提供参考。更多还原

【Abstract】 Two intermediate reheat adopted in the conventional Rankine cycle.is the double reheat technology,this technique can effectively improve the efficiency of the whole thermal cycle.With the development of steam turbine technology,the new type of primary reheat unit has increased the inlet steam parameters to the limit that the high temperature material can bear.Therefore,in order to further improve unit efficiency and reduce coal consumption,the double reheat technology is an important way.After analysis,if the double reheat technology is applied to the million degree ultra supercritical unit,the thermal efficiency of the unit can be increased by 3.3% to 3.6% compared to the conventional reheat unit.According to the thermodynamic cycle analysis,the design of the steam turbine is faced with such problems as the increase of the main steam pressure,the increase of reheated steam temperature,and the addition of a high temperature reheat cylinder to the shaft system.Especially,the design of high temperature and high pressure parts on steam turbine has brought great challenges.The valve,as one of the key components of the steam turbine,needs to bear the highest inlet steam temperature and the inlet steam pressure.The working environment is in bad condition.In this paper,the high pressure valve of the double reheat unit is taken as the object of study.The flow characteristics,strength performance and fatigue life of the valve are calculated,analyzed and evaluated.First of all,by the software CFX as a platform to CFD flow calculation,the high pressure valve of double reheat unit would be analyzed.Through the different flow conditions of three-dimensional steam flow analysis,flow field characteristics and the loss of high pressure valves would be obtained.Then high pressure valves performance of double reheat unit would be analyzed.Secondly,based on the finite element software Abaqus,the high pressure valve of double reheat unit would be calculated and analyzed.According to the steady temperature field analysis,stress field analysis and high temperature creep strength analysis of valve body,the performance of the valve in the structure intensity would be achieved.Finally,by the research of structure stress of valve after hot or cold shock on the valve,the variable load、unit start and stop conditions affected the valve life analyzed.The life loss under different working conditions is obtained,which provides a basis for the on-site operation of the start-up and shutdown of the control unit.Through this study,can ensure that the high pressure valve of the double reheat unit was developed successfully.It lays a good foundation for the successful development of the double reheat unit.and provide reference for the analysis and research methods of the same type of high temperature parts.更多还原