含腐蚀缺陷输气管道高频声致振动响应规律数值模拟

中国石油大学(北京)机械与储运工程学院·油气管道输送安全国家工程研究中心

输气管道;腐蚀缺陷;声致振动;疲劳失效;高频激励;能源研究所导则

Numerical simulation of the law of response to high-frequency acoustic-induced vibration along gas pipeline with corrosion defects
CHEN Yanfei,LIU Yu,HU Dong,YIN Yi,HE Mingchang,JIANG Nan

College of Mechanical and Transportation Engineering, China University of Petroleum (Beijing)//National Engineering Research Center for Pipeline Safety

gas pipeline, corrosion defect, acoustic-induced vibration, fatigue failure, high-frequency excitation, Energy Institute guidelines

DOI: 10.6047/j.issn.1000-8241.2024.04.005

备注

【目的】气体通过减压装置时产生的高频声学能量会激发输气管道管壁的高阶模态,导致管道结构出现声致振动,可能引起焊接支架、三通及管道腐蚀缺陷等不连续点处在短时间内发生疲劳失效。【方法】通过计算噪声谱,将声功率级转换为声压级,量化了声源强度的影响;构建了含腐蚀缺陷的输气管道声致振动有限元模型,并将声压施加于模型管壁,研究了无量纲腐蚀缺陷长度、宽度及深度对输气管道声致振动的影响,并与英国能源研究所(Energy Institute,EI)导则评估结果进行对比。【结果】在不同的无量纲腐蚀缺陷长度下,输气管道的应力响应呈现出驼峰状变化,即应力水平随无量纲缺陷长度的增大先增后减,但应力集中现象随无量纲缺陷长度的增大而减弱;随着无量纲缺陷宽度的增加,输气管道的分布趋于均匀;管道应力随着无量纲缺陷深度增大呈马鞍形变化,即输气管道的应力水平先降后升。【结论】腐蚀缺陷的存在显著影响输气管道的应力响应,尤其是腐蚀缺陷长度对管道应力影响最为显著,但当无量纲腐蚀缺陷深度增至0.6后,其对输气管道应力、振动模态的影响显著增大,今后应重点关注腐蚀缺陷深度对声致振动的影响。通过对含腐蚀缺陷输气管道声致振动响应的定量分析,既为解决管道强烈振动问题提供了理论支撑,也为输气管道设计、建设及运维提供了参考依据。(图 10表5,参[19]
[Objective] High-frequency acoustic energy generated by gas passing through decompression devices induces high-order modes of the pipeline wall, leading to acoustic-induced vibrations of the pipeline structure. These vibrations can potentially trigger fatigue failures at discontinuous, such as welded supports, tees, and areas of pipeline corrosion defects, over a short period. [Methods] Initially, the influence of sound source strength was quantified by calculating the noise spectrum and converting the sound power levels into sound pressure levels. A finite element model was created to simulate acoustic-induced vibrations in a gas pipeline featuring corrosion defects. Acoustic pressure was applied to the pipeline wall within the model to investigate the impact of corrosion defect dimensions on acoustic-induced vibrations, i.e. length, width, and depth. Subsequently, the obtained results were compared against the evaluation outcomes derived from the Energy Institute (EI) guidelines. [Results] Under varying dimensionless lengths of corrosion defects, the gas pipeline exhibited stress responses characterized by hump-like fluctuations. Specifically, the stress level initially increased and then decreased corresponding to increases in dimensionless defect length. However, the stress concentration weakened with increasing dimensionless defect lengths. As the defect width increased, the gas pipeline showed a uniform stress distribution. Additionally, the pipeline stress fluctuated in a saddle shape with increases in dimensionless defect depth. Specifically, the gas pipeline experienced initial decreases followed by rises in the stress level. [Conclusion] This study reveals the substantial impact of corrosion defects on gas pipeline’s stress responses, highlighting the most noticeable impact from the length of corrosion defects. Furthermore, corrosion defects with dimensionless depths over 0.6 lead to significant increases in their influence on the stress and vibration modes of gas pipelines. Consequently, future research should focus on investigating the impact of corrosion defect depths on acoustic-induced vibrations. The quantitative analysis outcomes of acoustic-induced vibration responses in gas pipelines with corrosion defects not only offer theoretical support for mitigating strong vibrations of gas pipelines but also serve as a reference basis for gas pipelines across design, construction, operation, and maintenance stages. (10 Figures, 5 Tables, 19 References)
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