Abstract: A mathematical model for accidental gas release in long transmission pipeline was given,on the basis of computational fluid mechanics.It is found that the existing model for describing hole on a pipe is suitable for predicting gas release through a small punctured hole,while the other existing pipe model is suitable to predict the gas release through a complete break of a pipe.In this paper,a new model for the hole diameter that lies between the above two situations was proposed.The calculation results of an example show that when the initial pressure inside the pipe is higher than 1.5 MPa,the mass of gas released during sonic flow is more than 90 percent of the total mass of the released gas.The total average rate of released gas could be substituted by 30 percent of initial released rate.This approximation would become more accurate with increasing the pressure inside the pipe.

Key words: long-distance transmission pipeline, released gas rate, critical flow, mathematical model, calculation

摘要： 应用计算流体力学理论,给出了长输管线气体泄漏率新的计算方法.当管线破坏的孔径较小(属于小孔泄漏)时,采用孔模型计算气体泄漏率;当管线发生全截面断裂时,利用管线模型计算;孔径介于两者之间时则利用新推荐的方法.由计算实例可知,管内起始压力大于1.5MPa时,临界流阶段泄漏的气体质量占总泄漏质量的90%以上,可用临界流阶段的平均泄漏率代替总平均泄漏率;也可用起始泄漏率的30%近似代替总平均泄漏率.随管内起始压力的增加,这种近似效果更好.利用文中的数学模型可以较好地估算不同孔径的气体泄漏率,可为定量评价长输管线失效后对环境的影响提供依据.

关键词: 长输管线, 气体泄漏率, 临界流动, 数学模型, 计算方法