Numerical investigation of heat transfer and flow characteristics of laminar flow in a tube with center-tapered wavy-tape insert

In this study, a new type of insert, named center-tapered wavy-tape insert, which is designed from bionics based on the movement of cuttlefish, is introduced. The thermo-hydraulic performance of laminar flow in a plain tube fitted with a center-tapered wavy-tape insert under constant heat flux conditions was investigated using numerical simulation. Further, the results were compared with the conventional wavy-tape insert. It was observed that the center-tapered wavy-tape inserts have a significant influence on the reduction of flow resistance and improvement of the overall performance for producing a similar flow structure and temperature field inside the tube with a small disturbance to the core area. The optimal conditions of use of the center-tapered wavy-tape insert were studied. The considered geometric parameter combinations of the model are provided herein. The best Nusselt number could be enhanced by 5.23-8.99 times and the best performance evaluation criterion could be improved to 2.62. Then, two empirical formulas were developed for predicting Nu and f with an error band of +/- 14%. Finally, the numerical results were verified by the Stereo-PIV experiments.