将氢气掺入已有天然气管道混合输送,被视为低成本转运绿色氢能的重要手段。利用计算流体力学方法数值研究了不同浓度氢气注入天然气管道后的混合过程,对比分析了不同注氢位置、不同注氢管径以及不同注氢量对均匀掺混距离的影响。结果表明：相较于从管道上部或下部注入,从管轴注入达到均匀混合的距离最短,这与注氢口下游气流的湍动强度有关;当从中部注入时,随着注氢管径的增加或注氢量的减小,管内气流湍动强度增强,均匀混合所需的距离缩短。因此,在工况允许的条件下,将注氢口伸至天然气管道管轴处,并适当增大注氢管径,可以实现较快的均匀掺混。

The mixed transmission of natural gas with injected hydrogen is an important means of transporting the green hydrogen energy at a lower cost. The mixing process of injecting hydrogen with different concentration in natural gas is numerically simulated in this research using the computational fluid dynamics method. The effects of the injection position and size of injection tube and the injecting flux of hydrogen on the required length to achieve uniform mixing are examined. Compared with injection from the upper or lower part of the pipeline, injection from the pipe axis resulted in the shortest distance to achieve uniform mixing; as this is dependent on the turbulent intensity downstream the injection point. When injection from the axis of the pipe, the turbulent intensity is enhanced with the increase of the diameter of injection tube or the decrease of injecting flux, resulting in the shortened required length for uniform mixing. Therefore, when operating condition permits, it is recommended to arrange the injection tube at the pipe axis and to enlarge its size appropriately so as to achieve faster and uniform mixing.