Effects of Shape and Quantity of Helical Baffle on the Shell-side Heat Transfer and Flow Performance of Heat Exchangers

Shape and quantity of helical baffles have great impact on the shell-side performance of helical baffled heat exchangers (HBHE). In this work, three physical models of HBHE with baffles of different shape (trisection, quadrant and sextant sector) were investigated. Numerical simulations were performed on HBHE at three helix angles (10 degrees, 25 degrees and 40 degrees) by the software ANSYS CFX. Analyses of numerical results indicate that the sextant HBHE shows relatively better fluid flow performance because the leakage flow in the triangle area is evidently reduced and the fluid streamline appears much closer to an ideal spiral flow, while the trisection and quadrant HBHE show more scattered and disordered streamline distributions. The convective heat transfer coefficient and pressure drop in three types of HBHE were presented. Further investigations on the shell side performance with different helical baffles were implemented by the field synergy theory. Both theoretical and numerical analyses gave support on the relations between helical baffle shape and shell-side performance. This paper may provide useful reference for the selection of baffle shape and quantity in HBHE.