300 MW机组三通的结构应力分析与形状优化

提出一种降低300 MW汽轮机组主蒸汽管道T形异径三通结构应力的设计方法。该方法利用三通在工作载荷下的变形数据修正原有结构。首先使用ANSYS5．7建立一个有限元分析模型，然后用实验结果考核了模型的有效性。在这个模型的基础上，计算不同修正量下结构的最高应力。发现三通肩部内壁转角处的应力水平随修正量的增大而减小，并且结构的最高应力呈现波动变化。在最大修正量达到原结构尺寸8．65％时，结构的最高应力可以下降45．9％。表明该方法能有效地降低这种三通的应力水平。这一结论为进一步改进三通的结构设计提供了理论依据。

STRESS ANALYSIS AND OPTIMIZATION FOR A TEE OF 300 MW TURBINE SET

A design method is presented, which can lower stress of T-typed unequal-diameter tee used by main steam pipe of 300?MW steam turbine set. The method use displacement data to modify original design and then a new design is obtained. A finite element model of tee is built in ANSYS 5.7 and reliability of the model was confirmed by an experiment. Based on the model, structure stress is calculated under different modified quantities. It is found that the stress level decreases in the corner of inner surface between main pipe and branch pipe in the shoulder when a modified quantity increases and max stress of the tee is fluctuant. While maximum of a modified quantity is up to 8.65% of structure size, maximum stress intensity is down to 45.9%. It shows that the method can effectively lower the level of this kind of the tee.