A parametric study on optimization of ring inserted heat exchanger tube

This study presents a parametric optimization of ring inserted heat exchanger tube according toNusselt number and friction factor. The heat exchanger tube was heated with constant heat flux and flowconditions is turbulent corresponding to Reynolds number of 25,000. Inner diameter, thickness and pitchlengths of the rings were considered as factors and each factor is composed of five various levels. The studywas carried out by using a computational fluid dynamics program that is Ansys-Fluent 18.0. Realizable kepsilon turbulence model is employed to simulate the turbulent flow condition. The results showed thatinner diameter, thickness and pitch length of the rings increases, the Nusselt number and the friction factortend to decrease. The configuration of the ring inserted heat exchanger tube provides the highest Nusseltnumber which is the inner diameter of 17mm, the thickness of 4 mm and the pitch length of 50 mm. On theother hand, the configuration of the ring inserted heat exchanger tube provides the lowest friction factorwhich is the inner diameter of 25 mm, the thickness of 10 mm and the pitch length of 250 mm. When theresults are simultaneously optimized according to both the Nusselt number and the friction factor, it wasfound that the best configuration is the inner diameter of 25 mm, the thickness of 2 mm and the pitch lengthof 50 mm.