Abstract: During the process of reconstruction and enlargement of petrochemical unit and crude oil degradation inland, the unscheduled shutdown of oil processing enterprises caused by flow-induced corrosion occurred universally, which affected enterprise production, surrounding environment and public safety seriously. In view of the frequently failure for the outlet elbow piping system of REAC, the mechanism of pipeline erosion destroy which dues to corrosion and multiphase flow interaction was studied. The model elbow pipe was designed and the experimental parameters were determined based on ascertained similarity criterion and obtained characteristic data. Moreover, the simulated erosion experiments were performed on the self-designed loop test apparatus for multiphase flow erosion-corrosion, and the erosion critical characteristic parameters of model elbow pipe were obtained by computational fluid dynamics (CFD) simulation on the process of corrosion. The simulated erosion test and the result of model elbow pipe simulation show that the erosion critical velocity of model origin is 7.93 m·s^-1, and the maximum shear stress of model elbow is 2.21 Pa, which tend to agree to the position of maximum water phase. Furthermore, the mathematical equation that reflects the relationship between the critical characteristic of prototype model and that of test model were established by dimensional analysis method. The correction coefficient of similarity theory was therefore solved, and the erosion critical characteristics of real case were corrected and acquired. The reliability and accuracy of the tests on erosion critical characteristics and the results of amendments were verified by the thickness measurement data, and the critical shear stress that cased erosion-corrosion was about 1.79 Pa. The erosion tests and analysis methods were innovative, which provided scientific theories and experimental methods for the multiphase flow erosion prediction of various pressure pipe related to different industries.

Key words: hydrogen cracking, REAC outlet elbow pipe, similarity theory, similarity criterion, erosion tests, erosion critical characteristics

摘要： 针对加氢REAC系统的频繁失效问题，研究流动与腐蚀耦合作用下REAC出口弯管的冲蚀破坏机理；在确定相似准则的基础上，结合具体的工艺特性运行数据，设计模型弯管，确定实验常数，并运用环道式多相流冲蚀实验装置，进行冲蚀瞬态特性测试，结合实验过程的CFD数值模拟获取模型弯管冲蚀瞬态特性参数。实验和仿真结果表明，模型弯管出现冲蚀瞬态特性时速度为7.93 m·s^-1，最大剪切应力为2.21 Pa；运用量纲分析法建立原型与模型冲蚀临界特性之间的数理方程，实现相似理论的求解，修正实验结果形成实际弯管的冲蚀瞬态特性参数，冲蚀剪切应力为1.79 Pa，结合工程测厚验证冲蚀瞬态特性测试实验和相似理论修正结果的可靠性和准确性；研究成果可为压力管道的多相流冲蚀预测提供科学的理论依据和实验方法。

关键词: 加氢裂化, REAC出口弯管, 相似理论, 相似准则, 冲蚀实验, 冲蚀瞬态特性