输气管道二元气体混合长度变化规律分析

运用模拟试验、平推流建模、数值计算与现场数据对比等手段,对输气管道二元气体的混合系数和混合长度进行了研究。在平推流模型求解过程中,为提高计算精度,将Taylor公式中的摩擦系数进行了修正。通过国内外10条天然气管道气体置换实例的对比分析,可知粗糙度对混合系数影响很小。同时,采用不同方法计算得出了二元气体的混合系数,Taylor-CW得出的混合系数平均比Taylor公式大1.1倍。在大管径、长距离、高流速的置换工况下,GR I(美国天然气研究所)公式混合长度计算结果与实测值误差较小。而对于小管径、短距离或者低流速的工况,用Taylor-CW公式能获得更真实准确的结果。

Analysis of binary gas mixing length variation rules in gas pipeline

By using the simulated test,plug flow model,numerical calculation and field data comparison means,binary gas mixture coefficient and mixing length of gas pipelines were studied.In the solution process of plug flow model,the friction coefficient of Taylor formula was amended in order to improve calculation accuracy.Through the comparative analysis for 10 gas pipelines of gas exchange examples at home and abroad,it indicates that roughness has little effect on the mixing coefficient.At the same time,the mixture coefficients of binary gas were calculated by different methods,and the mixing coefficient derived from Taylor-CW is averagely 1.1 times greater than that from the Taylor formula.In large diameter,long distance,high-flow velocity replacement operating conditions,the formula mixing length calculated results of GRI(U.S.Gas Research Institute) have less error with measured values.For the small diameter,short-range or low velocity conditions,a more realistic and accurate result can be got by using Taylor-CW formula.