The present paper is focused on the computational analysis of the flow field inside a vortex tube using RANS based two-equation turbulence model . The flow inside the vortex tube is a highly swirling one with very high values of swirl number. The current 3D CFD model was validated using published experimental data and was found to have a very good agreement in terms of total temperature predictions at the hot and cold outlets. The flow field was then compared to another published research study which utilized a higher order model, LES and was found to have qualitative differences between the tangential velocity profiles and the distributions of the free and forced vortex regions. The axial velocities and static temperature profiles on the other hand had a better agreement. With an idea of the strength and the weakness of the model, further analysis was done with respect to the flow properties i.e. Vorticity, Strain Rate and Reynolds Stress to provide a well-documented flow field of the flow inside vortex tube and explanations to the different phenomena observed are also presented.