Computational fluid dynamic modeling of methane-hydrogen mixture transportation in pipelines: Understanding the effects of pipe roughness, pipe diameter and pipe bends

A computational fluid dynamic modeling framework is developed to quantify frictional losses, assess the energy efficiency of transport, and characterize the mixing behavior of methane-hydrogen blends across representative regions of a large gas network such as transmission, distribution, and household pipeline sections. The principal conclusions from the present study are: (i) The increase in the energy required for transporting hydrogen as methane-hydrogen blends depends on the volume fraction of hydrogen, the nature of the flow conditions, pipe diameter, pipe roughness and pipe bends. (ii) Pipelines that have larger surface roughness or smaller diameters or those with bend sections require greater energy for transporting gas blends. (iii) The methane-hydrogen gas blends develop a core-annular flow pattern under steady state conditions with the denser and more viscous methane flowing near the pipe wall as the annulus while the less dense and less viscous hydrogen concentrated more towards the mid-sections of the pipelines.