【作者】 杜志锋；

【导师】 付忠广；

【作者基本信息】 华北电力大学 ， 热能工程， 2012， 硕士

【摘要】 随着国民经济的发展,我国用户用电量的不断增加,目前承担尖峰负荷的中小机组比例却越来越少,越来越多的大型汽轮机组需要参与调峰。频繁的启停、变负荷等非稳态工况运行,会使汽轮机转子温度变化增大,产生较大的温度梯度,从而产生较大的交变热应力,导致部件产生低周疲劳损耗；同时转子在恒定高温下长期运行,转子材料会发生蠕变现象,使其导致高温蠕变损耗；低周疲劳与高温蠕变的交互作用使转子产生裂纹,其逐渐扩展会导致转子断裂,这将严重影响机组运行的安全性。因此深入研究机组转子寿命损耗对确保电站设备的安全、经济运行具有重要意义。本论文第一部分介绍了选题的背景、意义以及国内外的研究现状；第二部分描述了一维递推算法和有限元算法的理论基础；第三部分以某电厂660MW超超临界汽轮机转子为研究对象,利用ansys软件对其进行模型的建立、网格的划分、边界条件的设定；第四部分模拟计算了机组冷态启动、温态启动、热态启动、正常停机的温度场、合成应力场,以及稳定运行时的等效蠕变应力场,利用非对称循环法、持久强度曲线计算了危险部位的致裂低周疲劳寿命损耗和致裂高温蠕变寿命损耗,在此基础上计算汽轮机高中压转子在蠕变和低周疲劳交互作用下一年的总裂纹萌生寿命损耗,并给出汽轮机安全、经济运行的建议。更多还原

【Abstract】 With the development of our country’s economy, the users of electricity consumption are increasing while a number of small and medium-sized unit is being out of service, more and more large steam turbine units are running on peak load. With frequent starting and stopping or variable load non-steady-state operating, temperature of steam turbine rotor will change sharply, which leads to a large temperature gradient and then produces larger alternating thermal stress, thus results to low cycle fatigue loss. At the same time, rotor runs in constant high temperature for a long term, materials creep phenomena will occur. So that it causes loss of high temperature creep. The interaction of Low-cycle fatigue and creep make rotor crack. Gradually extended cracks will make rotor fracture and will seriously affect security running of unit. So it is greatly significant for safe and economical operation of power plant equipment to in-depth study on the life loss of unit.The first part of this paper described the background, significance of subject, and the research status of domestic and foreign countries. The second part described the theoretical basis of a dimensional recursive methods and finite element algorithm. The third part made a660MW unit’s ultra-supercritical steam turbine rotors to be research object, using ANSYS software to established model, mesh and set boundary condition. The forth part used simulation to calculate the temperature field and stress field of the cold start-up, warm start-up, hot start-up and normal stop, and calculated the equivalent creep stress field of stable operation. Besides the paper used unsymmetrical cycled method and lasting strength curves to calculate dangerous section’s loss of low cycle fatigue and high temperature creep, and then calculated the total loss of high and medium pressure steam turbine rotor in a year time under the interaction of creep and low cycle fatigue. At last it gave suggestions of steam turbine safe and economic operation.更多还原