埋地输气管道发生天然气泄漏是严重的安全事件，会对经济和环境造成重大影响。针对大直径高压输气管道，采用计算流体力学（computational fluid dynamics, CFD）方法建立包含1.4 m直径管道及周围土壤的三维数值模型，研究高压气体经过预设泄漏孔在土壤中的泄漏特性。CFD模型将土壤考虑为多孔介质材料，采用Redilich-Kwong状态方程描述高压气体的温度-压力效应，结合组分输运和湍流模型，研究泄漏孔径、管内压力等因素对泄漏速率和温度分布的影响规律。结果表明：泄漏速率随着孔径、压力的增大而增大，当泄漏孔径在10 ~ 50 mm变化时，泄漏速率增加了77.78%；环境温度会导致土壤温度场分布呈现不同形式，环境温度较低时，管道内高温气体泄漏产生的温度-压力效应将被削弱；当环境温度与管内气体温度接近时，在泄漏口上方0.7 ~ 1.2 m埋地范围内产生可监测的温度变化区。研究成果有助于理解埋地大直径高压输气管道泄漏特性和温度变化规律，为管道泄漏监测光缆的布设提供理论依据。

The occurrence of natural gas leaks in buried gas pipelines is a serious safety event that can have significant economic and environmental impacts. For large-diameter high-pressure gas transmission pipelines, the computational fluid dynamics (CFD) method was used to establish a three-dimensional numerical model that included a 1.4 m diameter pipeline and the surrounding soil, to study the leakage characteristics of high-pressure gas through a pre-set leak hole in the soil. The CFD model considered the soil as a porous medium material, used the Redlich-Kwong equation of state to describe the temperature-pressure effects of high-pressure gas, and combined species transport and turbulence models to study the impact of leak hole diameter and internal pipeline pressure on leakage rate and temperature distribution. The results show that the leakage rate increases with the increase of hole diameter and pressure. When the leak hole diameter varies from 10 to 50 mm, the leakage rate increases by 77.78%. Ambient temperature can cause the soil temperature field distribution to take different forms. When the ambient temperature is low, the temperature-pressure effect produced by the leakage of high-temperature gas inside the pipeline will be weakened. When the ambient temperature is close to the temperature of the gas inside the pipeline, a detectable temperature change area is produced in the buried range of 0.7 to 1.2 m above the leak hole. The research results help to understand the leakage characteristics and temperature change patterns of buried large-diameter high-pressure gas transmission pipelines, providing a theoretical basis for the layout of pipeline leak monitoring optical cables.