Hydrogen gas stands as a renewable energy fuel for the transportation sector. The hydrogen to air ratio is an essential factor in deciding the combustion and therefore the thermal efficiency of an internal combustion engine. In this study, the mixing of hydrogen and air is considered among the four geometrical configurations. These cases are considered from the simple duct and vortex tube which induces an additional swirl inside a cylinder. The approach of the study involves the meshing and computation of mass, momentum and energy equations by finite volume method. After the convergence of results, mixture ratio is analyzed with the velocity components and vorticity variables. The ratio of hydrogen to air is found to vary between 8 and 35 among the cases considered. The desired ratio could be obtained from the combination of vortex tube and plain duct configurations. Stratification of mixture is found to be significant from the gradient of velocity components in this study. © 2021 Hydrogen Energy Publications LLC