Numerical investigation of helically coiled tube from the viewpoint of field synergy principle

The heat transfer characteristics of helically coiled tube are numerically investigated from the viewpoint of field synergy principle, and the simulation results have a good agreement with experimental results. The heat transfer enhancement of helically coiled tube can be attributed to the improvement of the synergy between the velocity vector and temperature gradient due to secondary flow, and the effects of Reynolds number, curvature ratio, and coil pitch on heat transfer performance can be well described by the field synergy principle. Moreover, the entransy dissipation augmentation number is proposed to evaluate the heat transfer performance of helically coiled tube, which is found to be suitable to evaluate heat transfer augmentation techniques. (C) 2015 Elsevier Ltd. All rights reserved.