Turbulent flow and heat transfer in a new type of internally torsion-ribbed helical tube

Adding inserts is an effective technique to enhance heat transfer in tubes. In this paper, a new internally torsion-ribbed helical tube is designed to enhance the heat transfer capability and improve the temperature uniformity inside the pipe by adding torsional ribs inside the tube. The flow and heat transfer characteristics of high-temperature heat transfer oil in a straight tube, a common helical tube, and a new internally torsion-ribbed helical tube are numerically compared. The results show that the presence of internally torsional ribs can effectively strengthen the fluid perturbation inside the tube and further weaken the boundary layer, thus improving the heat transfer effect. Moreover, the convergence of strong vortices in the fluid is weakened by 29.3% to 41.2%. The comprehensive heat transfer factor (PEC) of the internally torsion-ribbed helical tube is between 1.1 and 1.2, which is 11.1% to 12.0% higher than that of the common helical tube, and the temperature uniformity TU=0.18% is 72.3% better than that of the common helical tube. These data show that the new helical tube has excellent performance in strengthening heat transfer and preventing carbon deposition and coking caused by high local temperature of high-temperature heat transfer oil.