Numerical simulation of a buried hot crude oil pipeline under normal operation

A physical model is proposed to study the heat transfer and oil flow of a buried hot oil pipeline under normal operation. With certain physically reasonable assumptions, the governing equations for the thermal analyses are derived. An approach combining unstructured-finite-volume and finite difference methods is applied to solve the governing equations, in which the soil domain was discretized by unstructured grids. Numerical simulations in a wide range of operating conditions are conducted. The operating conditions cover 5 months (April, May, June, October and November) with throughputs ranging from 15,007 tons per day to 27,451 tons per day and outlet temperatures varying from 40.6 °C to 64.8 °C. Measured data are provided for comparison. A good agreement between numerical simulations and field measurement suggests that the proposed numerical scheme is a suitable method to simulate the heat transfer and oil flow of buried hot crude oil pipelines. We also analyze a number of influential factors on the temperature distribution of oil along the pipeline.