天然气在土壤中泄漏的稳态温度场分析

Analysis on Stationary Temperature Field of Nature Gas Leaks in Soil

埋地高压天然气经小孔泄漏会导致土壤冻结形成冻土,应用一元气体动力学、流体力学和传热学知识建立了天然气小孔泄漏吸热率模型和土壤稳态温度场模型,并进行了实例计算。结果表明:当天然气输送压力小于临界压力,小孔泄漏吸热率随压力的增大而增大;当天然气输送压力大于等于临界压力,小孔泄漏吸热率达到最大值;冻土厚度随土壤热导率或空气对流传热系数的增大而减小,但土壤热导率对其影响较小,空气对流传热系数对其影响较大。

The pinhole leakage of buried high pressure gas pipeline will lead to frozen soil. Applying the knowledge of gas dynamics, fluid mechanics and heat transmission science, the pinhole leakage absorption rate of heat model and stationary temperature field in the soil model are obtained. And the model is used in real calculation. The results show that if the pressure of pipeline is smaller than the chamber pressure, the pinhole leakage absorption rate of heat increases with the increase of pressure of pipeline. If the pressure of pipeline is as much or bigger than the chamber pressure, the pinhole leakage absorption reaches its maximum. The thickness of frozen soil reduces with the increase of soil＇s thermal conductivity and air＇s heat transfer co-efficiency, but the soil＇s thermal conductivity exerts relatively small effect on the scope of frozen soil, while relatively big effect on the air＇s heat transfer coefficiency.