The Safety Study on Shutdown of Daqing to Harbin Buried Oil Pipeline

After flow stoppage, the temperature of oil in the pipeline will go down. When it gets low enough, the oil pipelines will restart very difficult.Therefore, it is necessary to do rese arch work in order to protect the pipelines. In this paper, the overall coefficient of heat transfer of buried pip eline from Daqing to Harbin is calculated with two different ways, the location where the oil congeals first is found out. A modified rectangular stable heat transfer physical model and the corresponding mathematical models are developed. These two models take the influenoes from the constant temperature of the earth's layer and soil thermal physical properties(thermal conductivity, temperature diffusivity etc.)into account. From this, finite differential software is programmed.Then, the finite differential software is used to simulate the changes in the temperature field of the soil, the oil temperature over time, and the flow stoppage time of the pipeline from Daqing to Harbin.