Modeling the effect of transients on the work of the pipeline
The article presents a study of heat transfer from the pipeline to the soil. The effect of simplifying the heat transfer model is investigated. In the course of the studies conducted using various configurations of the model being developed, stable, one-dimensional non-stationary and two-dimensional non-stationary models of the pipe wall and soil were studied. In the course of work, various solutions to the task were considered. A comparison was made of the possibility of solving the problem using analytical and numerical methods. When using numerical methods, various configurations of spatial and temporal discretization were tested depending on the purpose of the study. For a one-dimensional model, a scheme of concentric rings was proposed with a constant increase in their thickness as the distance from the pipeline was increased. For the two-dimensional model, the radial grid of splitting was considered optimal, which, as the distance from the pipeline goes, becomes perpendicular. This allowed us to achieve a high accuracy of calculation while maintaining the balance with the processing time of the simulation results. Also during the work various conditions for the entry of the stream into the pipeline were considered. The effects of rapid changes in gas mass flow and inlet temperature are investigated. These conditions are often found in large-diameter pipelines designed for gas exports. In such systems, marine and deep areas along the pipeline route are often found. Therefore, these studies will be relevant to optimize the operation of various types of gas pipelines. The paper also carried out a comparative analysis of the data obtained with the data on the industrial operation of the export gas pipeline.