In this study, different heat transfer mechanisms and flow conditions were investigated to determine the temperature distribution. For this purpose, we proposed a coaxial tubular heat exchanger with a hemispherical end for different thermal parameters. Our attention was focused on the effect of geometry on the thermal and dynamic characteristics of the flow and on the performance of the studied heat exchanger. The results obtained show a qualitative agreement between those obtained and those found in the literature with a difference mainly due to the difference in geometry (the hemispherical end of the heat exchanger) and the code used.