Numerical studies of combined multiple shell-pass shell-and-tube heat exchangers with helical baffles

Abstract

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.

In order to simplify the manufacture and improve the heat transfer performance, we have invented a combined multiple shell-pass shell-and-tube heat exchanger. The novel combined multiple shell-pass shell-and-tube heat exchanger (CM-STHXs) with continuous helical baffles in the outer shell-pass and other different baffles in the inner shell-pass was compared with conventional STHX with segmental baffles by Computational Fluid Dynamics method. The numerical results show that, under the same mass flow rate M and the same overall heat transfer rate Qm in the shell side, the CM-STHX with discontinuous helical baffles in the inner shell-pass has the lowest overall pressure drop DP, which was 13% lower than that of the segmental baffled STHX; The heat transfer rate Qm of the CM-STHX with discontinuous helical baffles in the inner shell-pass is about 2% and 12% higher than those of the CM-STHX with segmental baffles and disk-and-doughnut baffles in the inner shell-pass. The CM-STHX with discontinuous helical baffles in the inner shell-pass has a much better heat transfer performance and can be used to replace the conventional STHX with segmental baffles in industrial applications to save energy, reduce cost and prolong the service life.