In the present research, numerical simulations of the turbulent, three-dimensional fluid flow, heat transfer, and friction for shell and tube heat exchanger using ANSYS FLUENT CFD technique are performed. The studied parameters are Nusselt number and friction factor at different values of mass flow rates (from 0.5 kg/s to 2.0 kg/s of water fluid flow) with the corresponding effect on thermal enhancement factor, and a correlation relating heat transfer and friction for different vane swirlers diameters and blade angles have been developed. The investigated cases are the case of plain tubes and different cases with inserted vane swirlers of different blade angles (15º, 20º, 30º, 35º, 40º, 45º and 60º) and swirler diameters (5, 10, 15, 18, and 19 mm). The results showed that the highest achieved heat transfer enhancement is for ij = 19 mm and ș = 15º case, resulting in for Nusselt number, friction factor, and thermal enhancement factor times that of plain tubes case of 1.62, 58.75, and 0.42, respectively. Also, the margin for selecting the proper vane swirler is the required heat transfer enhancement level with the maximum permissible friction loss. Throughout the investigation; numerical validation is carried out by comparing the numerical predictions obtained from the present model with the results reported in the literature. Fair agreement is found among both results.