Experiments on Heat Transfer Enhancement in 3D Inner Finned Helical Pipe

Experiments were performed to investigate the enhancement performance of single-phase flow and boiling heat transfer in the 3D inner finned helical pipes. The experimental results of two finned helical pipes with different inner fin geometry showed that the heat transfer and flow resistance in the 3D inner finned helical pipe gained greater augmentation than those in the smooth one. Within the measured range of Reynolds number, the average augmentation ratio of heat transfer for the two finned pipes are 71% and 103%, respectively, compared with the smooth helical pipe, and flow resistance are 90% and 140%. The tests for boiling heat transfer were carried out in the 3D inner finned helical pipes with the curvature of 0.0605 and the length of 0.668m.Comparied with that in the smooth helical pipe, the boiling heat transfer coefficient in the 3D finned helical pipe had been increased by 40% to 120% under various mass flow rates and wall heat flux, and the flow resistance coefficient increased by 18% to 119%.