Abstract:

The calculation method of critical temperature was discussed when the flow state of oilwas changed on buried crude pipeline. The change of flow state and flowmodel judged by critical temperature on buried crude pipeline was put forward. On the basic of the change physic parameters ofoil and general heat transmission factorwith temperature and friction generating heat.he mathematical model was established on axial temperature drop when buried crude pipelinewas running. Calculation meth-od ofmathematicalmodelwas studied. The process of calculating axial temperature drop mathematical model was presented when buried crude pipelinewas running. The resultwas close to factbetter, because the change of physic parameter of oil and general heat transmission factorwith temperature is considered in the model

Key words: crude pipelin, critical temperature, flow state, axial temperature drop