基于CFD和灰色理论的含缺陷管道冲蚀剩余寿命研究

Remaining erosion life of pipelines with defects based on CFD and grey theory

为降低管道输送系统受固液两相流冲蚀磨损影响导致的失效行为,以30°弯管为研究对象,采用Fluent软件建立了含缺陷管道的冲蚀模型,并对不同缺陷尺寸和服役时间下的冲蚀特性进行了分析,随后基于灰色理论建立了多个壁厚减薄量预测模型,最后结合冲蚀状态损伤分级标准,对管道剩余寿命进行了评价。结果表明,30°弯管下形成的冲蚀磨损核心区和影响区的划分不明显,在轴向角度0°~45°区域内的冲蚀速率较大;缺陷深度和缺陷长度对最大冲蚀速率的影响较大;GM(1,1)模型、无偏灰色模型、无偏灰色-马尔科夫链模型的平均相对误差分别为3.92%、2.71%、0.69%;现场验证结果中壁厚减薄量预测值与实际值的最大相对误差为6.47%,证明了无偏灰色-马尔科夫链模型的可靠性和优越性。研究结果可为定期开展弯管等重点部位的无损检测提供实际参考。

In order to reduce the failure behavior of pipeline transportation systems affected by erosion wear caused by solid-liquid twophase flow,the erosion model of pipelines with defects was established by using Fluent software with a 30°bending pipe as the research object,and the erosion characteristics under different defect sizes and service time were analyzed.Then,multiple prediction models of wall thickness thinning were established based on gray theory.Finally,the remaininglife of the pipeline was evaluated according to the state damage classification standard of erosion.The results show that the division of the coreerosionwear zone and affected zone in the 30°bend pipeis not obvious,and the erosionrate is larger atthe axial angle of 0°~45°.The defect depth and defect length have a great influence on the maximum erosion rate.The average relative errors of the GM(1,1)model,unbiased grey model,and unbiased grey-Markov chain model are 3.92%,2.71%,and 0.69%,respectively.The maximum relative error between the predicted value and the actual value of wall thickness thinning is 6.47% during site verification,which proves the reliability and superiority of the unbiased gray-Markov chain model.The research results can provide a practical reference for regular non-destructive testing of bending pipes and key parts.