天然气管道动态泄漏率的数值研究

摘要

The leakage rate of natural gas is one of the important factors that affect the safety of evaluation of the pipeline, the calculation of which can provide a numerical basis for safety evaluation.According to the calculation model of the dynamic leakage rate of natural gas pipelines, the leakage rate of the critical leakage phase and the sub critical leakage phase in different operating conditions were calculated by using Matlab software.The results show that the change of leakage rate is larger in the critical leakage phase than that in the sub critical leakage phase.The critical leakage phase is much longer than that of the sub critical leakage phase.The factors influencing the dynamic leakage rate are the leakage aperture, the quality of residual gas in pipe and the initial pressure.When other conditions are the same, the pipeline with large leakage aperture has a big initial leakage rate and great changesin the leakage rate while the time of leakage is short.Different quality of the residual gas in pipelines has no effect on the initial leakage rate, but the pipeline with quality of residual gas has a small change in leakage rate,and the leak lasts for a long time.The pipeline with large initial pressure has a large initial leakage rate and it takes more time for gas leakage.%天然气泄漏率是影响管道安全评价的重要因素之一,能够为安全评价提供数值依据.根据天然气管道动态泄漏率计算模型,利用Matlab软件分别计算了不同工况下临界泄漏阶段和亚临界泄漏阶段的泄漏率,从而获得了动态泄漏率的变化规律和不同因素对动态泄漏率的影响.结果表明:泄漏率在临界泄漏阶段变化率较大,在亚临界泄漏阶段变化率较小,临界泄漏阶段所用的时间远远长于亚临界泄漏阶段.影响动态泄漏率的因素有泄漏孔径、初始管内剩余气体质量、初始压力等.在其他条件相同时,泄漏孔径大的管道初始泄漏率和泄漏率的变化都大,泄漏所用时间短.不同初始管内剩余气体质量对初始泄漏率没影响,但剩余质量大的管道泄漏率变化小,泄漏持续时间长;初始压力大的管道初始泄漏率也大,泄漏所用的时间长.