原油长输管道顺序输送动态传热特性研究

Study on Dynamic Heat Transfer Characteristics of Batch Transportation in Long Distance Crude Oil Transportation Pipelines

长输管道冷热原油顺序输送是为了使冷油通过后热油也能安全地通过管道输送进站,因此对于周围环境的土壤温度场具有严格的要求。以传热学和流体动力学理论为指导,建立长输管道中的流体流动与传热的基本模型,再利用数值模拟,对长输管道冷热原油顺序输送时不同轴向位置的土壤温度场和轴向油温间的对应关系进行相关拟合研究。结果表明:当管道输送的原油量较小时,输送距离超过相关值后,管道沿线不同位置的温度近似保持一定值;而当管道冷热原油顺序输送时,由于油温不断交替变化,使得管道内油温及周围环境的土壤温度场随之不断周期性变化,但会发生空间滞后性,并且在输送热油时,由于管道受之前运送冷油的温度影响,热油头进站温度达到最低值,这是在编制安全运行方案时应重点考虑的因素之一。

Cold and hot crude oil batch transportation in long distance transportation pipelines is for the safe passing of hot oil through the pipeline to the station after the passing of cold oil. Therefore,requirements for the soil temperature field of surrounding environment are very strict. Based on the theory of heat transfer and fluid dynamics, the basic model of the fluid flow and heat transfer equation in underground long distance transportation pipelines is established,and numerical simulation is used to conduct relevant fitting study on corresponding relationship between soil temperature field and axial temperature under different axial position coordinates during the batch transportation of cold and hot oil in long distance transportation pipelines.The results show that when the pipeline transportation amount of crude oil is small and the transportation distance is greater than relevant value,temperatures at different position coordinates along the pipeline are approximatively the same. When the batch transportation of cold and hot crude oil conducts, the temperature is changing alternately, making the pipeline oil temperature and the soil temperature field of surrounding environment change periodically accordingly.But spatial lag will happen,and when conveying hot oil,because of the temperature influence of cold oil transport before, the inlet temperature of will reach the lowest temperature, which should be one of the factors mainly considered in the preparation of safety operation scheme.