2024/07/04 by Arabey, Andrey Borisovich, Kaputkin, Dmitry Efimovich, Istomina, Tatiana Yuryevna +2
#FOS: Materials engineering #Materials engineering
paper · doi:10.48612/letters/2024-2-119-124
During the mainline transportation, the flow of natural gas is always turbulent (Reynolds number Re =106…1010), accompanied by pressure fluctuations that cause previously unexplored small-amplitude oscillations in mechanical stress in the pipe wall, manifested in the acoustic effect (hum) observed in practice for gas pipelines. These stress fluctuations with an amplitude of no more than a few percent of the yield strength affect the pipe walls throughout the entire period of operation (40 – 50 years or more), so the total number of accumulated cycles can reach 1012. According to the authors’ hypothesis, when the protective coating of the pipeline is damaged and the wall contacts with ground electrolyte, such ultra-high-cycle low-energy corrosion-mechanical influence can be one of the factors of stress corrosion damage to the main gas pipeline. Theoretical evaluation and computer simulation showed that the resonant frequencies of oscillations of the gas in the pipeline and of the pipe wall could coincide (e. g., for the pipe diameter of 1020 mm — about n ∙ 800 Hz, where n means the harmonic number). Experiments confirmed this effect.