In the present study, computational fluid dynamics techniques are used to investigate numerically the performance of a heat exchanger (shell and helical tube) in order to improve its ability of transferring the heat through its body. The heat exchanger model includes a helical tube, a shell and baffles where the latter are of a cone shaped and distributed in the center and in the shell side. The angle and length of baffles are taken to be varied in the range of 0 degrees to 90 degrees and 10 cm to 35 cm, respectively. The major findings of the thermal analyses show that due to the baffles shape of the shell, the fluid moves inside the domain, with continuous baffles, and varies significantly, which is resulted in a significant increase in the heat transfer coefficient in the heat exchanger. The maximum amount of the transferred heat was obtained at the angle of 80 degrees and length of 30cm of the baffle.