高气液比倾斜管临界携液流速研究

摘要

天然气在管道输送过程中,随着温度和压力的降低会产生凝析液,凝析液聚集在管道的低洼处形成积液,不仅堵塞管道影响输气效率,而且腐蚀管线.生产中,通常采用提高气速的方法排出管道积液,能够使得管道积液从低洼处被携出的最小气速为该管道的临界气速.文中根据倾斜管内液相的基本动量方程,进行适当假设,建立倾斜管临界携液模型,并设计地势起伏的管路与实验管架,进行不同工况的实验,以确定管道的临界携液气速.另外还挑选出合适的气液界面摩擦系数,代入临界气速方程进行求解.结果对实验值与模型计算值进行对比,吻合度较好,其中Linehan的气液界面系数更适用于黏度较小流体模型的计算,Wongwises的气液界面系数则更适用于黏度偏大的流体.%Nature gas will produce condensate with the decrease of temperature and pressure during pipeline transportation.Condensate will accumulate to form effusions in low-lying areas of the pipes,which will not only block pipelines,affecting gas transmission efficiency,but also corrode pipes.In actual production,gas velocity tends to be improved so as to remove effusions.And the minimum gas velocity,which will allow effusions removing from low-lying areas of the pipes,is the critical gas velocity.According to the basic momentum equations of the liquid phase in the inclined tube,some appropriate assumptions are made and a critical liquid-carrying model is established in the paper.Then undulating pipes and the testing pipe rack are designed to do experiments under different conditions in order to determine the critical liquid-carrying gas velocity of the pipeline.Besides,the appropriate friction coefficient of the gas-liquid interface was selected and substituted into the critical gas velocity equation to solve equations.The result shows that the experimental results are well consistent with the model calculation values.In addition,Linehan's gas-liquid interface coefficient is more suitable for the calculation of low viscosity fluid model while Wongwises gas-liquid interface coefficient is more suitable for fluid with large viscosity.