通过研究汽水分离器启动过程的应力分布，准确预测其疲劳寿命，可为锅炉设计、运行维护检修、启动过程优化提供依据。以某超临界600 MW 机组锅炉汽水分离器为研究对象，运用有限元法模拟了汽水分离器在冷态启动过程中的温度场、应力场分布，通过工质压力计算一次应力，并对热应力和一次应力进行耦合得到峰值应力。结果表明：热应力主要受分离器内外壁温差影响，随着内外壁温差的增加，热应力增大；一次应力由工质压力决定，当工质压力达到最大时，一次应力也达到最大；汽水分离器内壁靠近引入管开孔的上端区域峰值应力变化梯度较大，存在明显的应力集中现象，最大峰值应力位于该区域分离器筒体与引入管内壁的相贯线上端，该区域即为汽水分离器冷态启动过程中的危险区域，可作为锅炉运行维护检修的依据。%Investigation on stress distribution in steam water separator during start-up process can accurate-ly predict the separator's fatigue life,thus to provide references for boiler design,operation maintenance and start-up process optimization.Taking a supercritical 600 MW unit boiler's steam separator as the research object,the temperature and stress distribution during cold start-up process was simulated,by finite element method.Moreover,the working medium pressure was used to calculate the primary stress,then the primary stress was coupled with thermal stress to obtain the peak stress.The results indicate that,the thermal stress is mainly affected by temperature difference between internal and external wall of the separator. With the increasing temperature difference between the inner and outer wall,the thermal stress increases. The primary stress depends on the working medium pressure.It reaches the maximum when the working medium pressure increases to the highest value.The gradient of peak stress on the inner wall near the up-per opening area of the introducing tube is great.There is obvious stress concentration in this region.The maximum peak stress located in this region's inner intersecting line between the separator cylinder and inlet pipe.Therefore,this region will become dangerous during the cold state start-up process,which should be paid more attention during the maintenance.
展开▼
