Analysis Of Stress And Vibration Characteristics Of ANAN Pipeline Station

Gas gathering station is an important hub of the gas transmission pipeline system. Normal running of its equipment and pipelines plays an important role in the safe transportation of gas. The inlet pipeline of ANAN gas gathering station includes the buried pipeline and the pipeline on the ground. Complex structure, two-phase flow and high fluid pressure in the inlet pipeline make it prone to stress exceeds the allowable stress and vibration problems. Analyze the stress distribution and vibration characteristics of the inlet pipeline in ANAN gas gathering station are necessary to make it operate safely.Firstly, the software CEASARII is used in this analysis work according to design information. It is used to check the stress at the elbow of buried pipelines. It is also used to check the level of the first stresses and the second stresses of inlet pipelines according to the related standard. Through comparison and selection, the optimal design scheme of the inlet pipeline is determined.Secondly, from the perspective of fluid in pipeline causes vibrations, with hinged beam model, the free vibration equation of two-phase flow is established. The natural frequency and the instability critical velocity based on the equation are solved. The effect of structure and fluid parameters to the natural frequency is analyzed with MATLAB software. Sensitivity analysis of the impact of the fluid parameters on natural frequency is performed through the orthogonal experimental range method. The result shows that void fraction and oil density have a significant impact on the natural frequency. Flow rate and density of nature gas have little impact on the natural frequency.Finally, fluid parameters affecting the characteristics of fluid-structure interaction are analyzed by ANSYS Workbench software. The results show that the effect of fluid-structure interaction may reduce the natural frequency, but it can be ignored to modal shape. According to the results of modal analysis, harmonic analysis is carried out on the inlet pipeline to obtain the relationship between displacement and frequencies. Analysis of harmonic response also find out the peak frequency of the inlet pipeline possible to resonate and the stress and displacement under peak frequency. The results show that the maximum stress and displacement response of the inlet pipeline occur under the first natural frequency. Tee joint and the middle of the inlet pipeline are the main monitoring parts in the process of operation. The vibration protection measures of gas-liquid two-phase flow pipelines are provided.