火电调峰机组导汽管的疲劳损伤

Fatigue damage of steam conduit in thermal power peaking unit

为了研究火电机组调峰运行对设备的损伤情况,采用有限元软件对某导汽管在调峰运行工况下的应力变化进行分析,结合材料的疲劳寿命数据对设备的安全状况进行评估。结果表明:仅考虑内压应力时,导汽管内壁应力约为40MPa,外壁应力约为27MPa;考虑热膨胀后,导汽管同样位置的内、外壁应力分别达到了98.73,62.159MPa;导汽管的应力受结构热膨胀应力的影响较大,但应力波动幅度降低;热膨胀应力对导汽管的疲劳寿命影响较大。

In order to study the damage of the thermal power unit to the equipment during the peaking operation,the finite element software was used to analyze the stress change of a steam pipe under the peaking operation condition,and the safety status of the equipment was evaluated based on the fatigue life data of the material.The results show that when only considering the internal pressure stress,the inner wall stress of the steam pipe was about 40 MPa,and the outer wall stress was about 27 MPa.After considering the thermal expansion,the stress of the inner and outer walls of the steam pipe at the same positionreached98.73 MPaand 62.159MParespectively.The stress of the steam pipe was greatly affected by the thermal expansion stress of the structure,but the stress fluctuation was reduced.Thermal expansion stress had a great influence on the fatigue life of steam pipe.