考虑离心力与热应力的组合转子裂纹扩展研究

摘要

组合转子工作在高温、高转速的工况下,启停过程中有较大的交变热应力和交变离心力,容易产生疲劳裂纹.针对某重型燃气轮机组合转子,利用有限元方法,分析组合转子启动过程中拉杆孔和透平拉杆的离心力和热应力分布以及离心力一热应力耦合时综合应力分布,确定应力集中位置,研究启停过程中离心力、热应力对组合转子裂纹扩展规律的影响.研究结果表明,综合应力最大、最易产生裂纹和裂纹扩展最快的位置是组合转子透平一级轮盘入口拉杆孔六点钟方向,离心力和热应力对组合转子综合应力分布有很大影响,在考虑裂纹扩展时不可忽略.%The combined rotor usually works under the situation of high temperature and high speed.Fatigue cracks easily occur because the centrifugal force and the thermal stress are continuously changed during start-up process of the combined rotor.In this article,the centrifugal force,the thermal stress and the coupling stress between the centrifugal stress and the thermal stress of combined rotor rod hole and rod were analyzed using the finite element approach and the stress concentration zone is found.The effects of centrifugal force and the thermal stress during start -up process of the combined rotor on the propagation of cracks were researched.The results show that the maximum stress and crack occurs most easily at six o'clock direction of the first disk rod hole which has the minimum critical crack size.The centrifugal force and thermal stress which have a significant effect on the distribution of stress cannot be ignored.