Turbulent heat transfer in tubular heat exchangers with twisted tape

Enhancing heat transfer in heat exchangers has gained attention of researchers for many years because of reduction in costs of generating heat exchanger. Application of improved tubes is one way of increasing heat transfer. In the present study, the turbulent flow in tubular heat exchangers with two twisted tapes was numerically investigated. Constant input velocity and output pressure with non-slip conditions on the surface of the tape and the tube were also considered as the hydrodynamic boundary condition. In addition, the constant heat flow and heat resistance boundary conditions were also considered for the surface of the tube and the tape, respectively. The fluent software was applied to solve the governing differential equations. Results indicated that reducing the torsion ratio at constant Reynolds number with unaligned orientation of tapes increases the average Nusselt number. Results also demonstrated that in aligned orientation, performance enhancement is more compared to aligned orientation.