Numerical Simulation of Heat Transfer Performance of a Dimpled Tubular Heat Exchanger

The processing of dimple on the outer wall of tube will produce corresponding protrusion dimple on the inner wall. The turbulent flow and heat transfer performance of a tubular heat exchanger containing a dimpled inner tube is studied numerically. The results show that the main reason for the enhancement of heat transfer ability of the dimple is the flow vortex in the concave dimple and the shock to the wall induced by the protrusion dimple. Compared with the smooth wall of the tube, the maximum enhancement of heat transfer was 1.94 times in concave dimple and 2.74 times in protrusion dimple. By comparing the heat transfer performance, flow resistance, and comprehensive heat transfer factor of the tube and shell of different sizes of exchange heat pipe, it is determined that the combination of inner and outer wall dimple size of 10-15 mm is a structure with better comprehensive heat transfer performance.

Automated summary

This study numerically investigates the turbulent flow and heat transfer performance of a tubular heat exchanger with a dimpled inner tube. The results demonstrate that the flow vortex in the concave dimple and the shock induced by the protrusion dimple are the main reasons for the enhancement of heat transfer ability. Compared to a smooth-walled tube, the maximum increase in heat transfer is 1.94 times in the concave dimple region and 2.74 times in the protrusion dimple region. By comparing different sizes of heat exchange pipes, it is determined that a structure with inner and outer wall dimple sizes of 10-15 mm exhibits better comprehensive heat transfer performance.