Numerical examination of the effect of new type turbulator placed in pipe on heat transfer

In this study, the effect of turbulators, designed at different pitch heights (H), on heat transfer and flow in the pipe was investigated numerically at different period lengths (Lp). Air was used as the working fluid.The improvement of the heat transfer was aimed by producing longitudinal vortices in the pipe with the use of turbulators. The pitch of the turbulator, whose geometry periodically repeats in flow direction, is designed asymmetrically from 1mm thick sheet metal. The time-averaged Navier-Stokes (RANS) and energy equations for turbulent flow in the pipe were solved in 3D by using ANSYS Fluent 19.2 CFD package program. Realizable k-ε model with Menther Lencher as near wall treatment was used to capture turbulant flow. A constant heat flux of 1000 W/m2 was applied on the heated surface. The effects of turbulator having different pitch ratios (HR: 0.31-0.47-0.63) and period lengths (PR: 1.4-1.9-2.5) on flow and heat transfer were examined numerically in the range of 5000-28000 Re number. It has been determined that the Nusselt number and the friction factor increases with increasing Re Number whereas The Thermal Enhancement Factor (TEF) decreases. In terms of TEF, the maximum value was calucalated as 1.16 for HR = 0.63 and PR = 1.4 at Re = 5000.