大功率汽轮机末级长叶片三维动态应力及服役寿命的研究

Study on 3-Dimensional Dynamic Stress and Service Life of Large Steam Turbines' Last Stage Blades

提出了一种预测汽轮机叶片服役寿命的综合数值模型。首先,开发了分析汽轮机叶片激振力、动频和动应力的计算模型,基于动应力的分析结果,提出了考虑制造和腐蚀环境等多种因素的汽轮机叶片服役寿命模型。给出了叶片材料的疲劳特性试验结果,为叶片寿命分析提供了必要参数据。此外,还对汽轮机末级680 mm叶片进行了分析。结果表明:所建立的叶片激振力、动频和动应力分析模型具有良好的工程精度,开发的叶片服役寿命分析模型可以定量考虑影响叶片寿命的各个因素,从而为在设计阶段及运行中保证叶片的可靠性提供了有力的依据。

A comprehensive model for predicting the service life of steam turbine blades is presented. First of all, calculation models, with which exciting forces acting on steam turbine blades, the latter＇ s dynamic frequencies and dynamic stresses can be calculated, were developed; followed by a proposed model, based on dynamic stress analysis results, for estimating the service life of steam turbine blades, which takes into consideration the manufacturing technology used and the erosive environment of operation, as well as other factors. Finally, a steam turbine＇s 680 mm long last stage blade is being analyzed with given experimentally based fatigue curve of the material and other necessary data. Results show that the exciting force, the dynamic frequency and dynamic stress analyzing models, all exhibit satisfactory engineering accuracy. This newly developed service life analyzing model is capable of qualitatively considering all factors that have an influence on the blades＇ service life, there with providing a strong basis for warranting the blade＇ s reliability already in the design stage as well as during operation. Figs 7 and refs 9.