In the course of transporting of heat oil in pipeline, heat transfer from heat -crude oil to soil because oil temperature is higher than soil temperature. As a result, the soil temperature rise, soil surrounding the oil pipeline has stored remarkable heat. When oil pipeline shutdown, The heat stored in the soil functions as delaying the oil temperature dropping. The function is also related to natural temperature. A definite solution problem on heat transfer is obtained. After finding the solution, the analytic solution of the changed soil temperature at any point outside pipeline has been obtained; the corresponding program software has also been programmed. Moreover, we have, measured the soil temperature in different directions on a real heat oil pipeline. The result shows that the measured value conforms to the calculated value basically. So the programmed software provides a scientific basic for determining safely shutdown time in various seasons.
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