蠕变疲劳交互作用下的高温转子寿命预测研究  

Life Prediction of High Temperature Turbine Rotor Under Creep and Fatigue Interaction

作　　者：王海涛 刘岩 杨彦磊 

机构地区：[1]上海电气电站设备有限公司汽轮机厂,上海200240

出　　处：《热力透平》2016年第4期253-258,共6页Thermal Turbine

基　　金：上海市科学技术委员会资助项目(13DZ1101500)

摘　　要：在锻造、加工及服役过程中,汽轮机转子表面或内部可能会产生缺陷。为保证含缺陷转子在全寿命周期内的完整性,需要执行可靠的缺陷转子剩余寿命预测及评定。采用参考应力法对高参数、大功率汽轮机含缺陷转子进行了寿命预测研究,结果证实,在启动、稳态运行及停机过程中,转子表面的应力状态以切向应力为主。将转子缺陷位置处的切向应力施加到高拘束单边缺口拉伸试样两侧,并以此裂纹尖端参考应力及应力强度因子来预测缺陷转子的服役寿命,其评定结果是保守、可靠的。分析寿命演化曲线后发现,转子中的裂纹尺寸及裂纹扩展速率随启停循环次数的增加而不断增大,蠕变疲劳交互作用加速缺陷转子的寿命损耗。采用拘束度过高的深裂纹试样来评价缺陷转子寿命,将得到过于保守的结果。研究指出,为保证缺陷转子在长寿命服役中的完整性,需要选取裂纹深度合适的等效试样,并对缺陷转子进行耦合损伤机制下的寿命预测及评定。The surface or internal defects may occur in steam turbine rotors in the process of forging, machining and service. In order to ensure integrity of a rotor with defects in the whole life time, the reliable residual life prediction and evaluation for the defect rotor are required. The residual life prediction for a high parameter and large capacity steam turbine rotor containing crack defect was investigated using reference stress method. The results prove that the tangent stress is dominant during the long-term operation of start-up, running and shut-down. With the tangent stress applied to a single edge crack in a flat plate, the life prediction for high temperature rotors is demonstrated to be more conservative and reliable according to the crack tip intensity factor and associated reference stress. In addition, it is found that the length and propagation rate of crack are increased with the increase of start-up and shut-down cycles and the interaction of creep and fatigue may accelerate the life loss of the rotor. And too conservative assessment will be obtained using specimen containing crack with exorbitant constraint. In order to guarantee integrity of high temperature rotor in longterm operation, equivalent specimen containing cracks with certain depth is selected to predict and evaluate the life time for defect rotor based on coupling damage mechanism.

关 键 词：高温转子 蠕变疲劳交互 参考应力法 寿命预测 

分 类 号：TK263.6[动力工程及工程热物理—动力机械及工程]