The heat exchanger, as the main element in various types of energy systems, is widely studied in technological and production processes to improve their performance and efficiency. There are various techniques available to enhance the performance of heat exchangers, but in recent years, vortex generators have gained significant attention. Vortex generators (VGs) is a passive control method that can improve heat transfer if properly designed. Vortex generators achieve enhancement by creating transverse, longitudinal, or normal twiddle flows, disrupting the flow field, and improving transport phenomena. The improvement in convective heat transfer coefficient is achieved by increasing fluid mixing, breaking down the thermal boundary layer, and enhancing mean velocity and temperature gradient. In this paper, a coaxial counter-flow heat exchanger was considered. Prism shape vortex generators were installed on the outer surface of the inner tube of the heat exchanger and resulting performance was compared to that of the same heat exchanger without vortex generators. RANS CFD study (SST k-ω turbulence model was used; this model predicts well near-wall turbulence, which is crucial when investigating the impact of vortex generators) demonstrated 13% improvement in heat transfer rate in case of heat exchanger with vortex generators.