Analysis on enhanced turbulent heat transfer and flow characteristic in a twisted and dimpled oval tube

This work reveals the heat transfer and flow characteristic in a twisted oval tube under turbulent constant flux conditions. Numerical analyses were carried out on several configurations. In order to clearly reveal effect of dimples swirl flow, tubes with without are considered. enhance convective transfer, placed narrowing region where was inefficient. The results indicate that significantly increase although they cause slightly pressure drop penalty. While decrease pitch length induced it negatively affected hydraulic performance tube. Furthermore, while induce average Nusselt number by 14.8%, friction factor 18.0%. best configuration is case dimpled having 200 mm at Reynolds 10,000, yields thermo-hydraulic criteria 1.428.