机组变负荷对省煤器入口管道焊接结构疲劳寿命影响的分析

Analysis of the Influence of Variable Load on Fatigue Life of Economizer Inlet Pipeline Structure in a Thermal Power Unit

研究某600 MW火电机组负荷变化对省煤器入口管道结构疲劳寿命的影响,采用材料拉伸试验、疲劳试验及数值模拟3种方法,分别得到应变与疲劳寿命之间的关系。结果表明:材料拉伸试验预测结构寿命与疲劳试验的偏差较大,而数值模拟结果与疲劳试验结果较为吻合,数值模拟方法能够合理评估结构疲劳性能,并且结构疲劳损伤随机组负荷变化幅度的增大而明显增大。

Researches were conducted on the influence of the variable load on the fatigue life of the economizer inlet pipeline structure in a 600 MW thermal power unit,the relationship between strain and fatigue life was obtained through following three methods,such as material tensile test,fatigue test,and numerical simulation method.Results show that,the fatigue life of material tensile test is quite different from that obtained by fatigue test,while the fatigue life of numerical simulation method is in accordance with that of fatigue test.The fatigue performance of the structure can be reasonably evaluated by numerical simulation method,while the life loss of the structure significantly increases with the increase of the change range of the unit load.