机动管线气顶排空速度的影响因素及作用机理分析

为提高机动管线的排空速度和机动能力，建立机动管线气顶排空的动力模型，采用特征线法求解，得到清管球速度和管内压力降的变化规律。利用该模型对排空过程进行了计算和实验验证，发现排空速度与空压机流量、压力以及管线的临界长度有关：当管线长度大于临界长度时，空压机的排气量起主要作用，使用大流量的空压机排空速度较快；反之当管线长度小于临界长度时，压力起主要作用，使用大压力的空压机排空速度较快。因此，为提高排空速度，可以在设计时首先计算临界长度，之后根据管线的总长度和临界长度选择性能合适的空压机，或者依据空压机的性能划分排空段的长度。

Analysis of the Influencing Factors and Mechanism of Gas Draining Rate of Mobile Pipeline

In order to promote the emptying efficiency of mobile pipeline,a dynamic model of emptying is established,which is solved by the method of characteristics (MOC),and the velocity of spherical pig and the variation of pressure drop are obtained.The model was verified by experiments.The emptying rate is related to the critical length of pipeline,the gas flow rate and max pressure of compressor.If the length of pipeline is longer than its critical length,the gas flow rate plays a dominant role in the emptying rate,and a high-flow-rate compressor should be used.On the contrary,if the length of pipeline is shorter than its critical length,the gas pressure plays a dominant role,and a high-pressure compressor should be used.The critical length increases with the development of pipe length,while the critical length decreases with the development of gas flow rate and pressure.Hence,in order to promote the emptying efficiency,the critical length should be determined in the design,and then an appropriate compressor is chosen in terms of the overall length and critical length of pipeline or the length of emptying segment is partitioned according the compressor performance.