An analysis of performance on trisection helical baffles heat exchangers with diverse inclination angles and baffle structures

Investigations of thermo-hydraulic performance were conducted on five trisection helical baffle heat exchangers with different inclination angles, baffle shapes, or connection patterns, and one segmental baffle heat exchanger (SEG). A comparative analysis of three sector baffle schemes with inclination angles of 10° (10°S), 15° (15°S), and 20° (20°S); an ellipse baffle scheme with an inclination angle of 15° (15°E); and an axial overlap sector baffle scheme with an inclination angle of 20° (20°D) was performed. Local images were constructed to obtain pressure loss characteristics and flow field distributions. The flow field characteristics, such as the Dean vortex secondary flow and bypass leakage between adjacent baffles, are clearly shown and discussed. The same inclination angle schemes have completely different properties because of the baffle shapes or connection patterns. The performance of the end-to-end scheme is superior to that of the axial overlap scheme, and the ellipse baffle scheme is inferior to the sector baffle scheme. The 20°S scheme has the optimum comprehensive index and lowest shell-side pressure loss. The 10°S scheme has the highest shell-side Nusselt number and shell-side pressure loss, and can be selected only when heat transfer capability is very important in an engineering application.