Numerical investigation of combined parallel two shell-pass shell-and-tube heat exchangers with continuous helical baffles

A combined parallel two shell-pass shell-and-tube heat exchanger with continuous helical baffles (CPTP-STHX) and an improved model (CPTP-STHX-improved) have been proposed to improve the heat transfer performance of shell-and-tube heat exchangers (STHXs). It is found that proportion of the mass flow rate of the inner shell pass to the total mass flow rate of the shell side is a constant. The heat transfer performance increases with the resistance of the inner shell pass. The CPTP-STHX-improved is compared with a conventional STHX with segmental baffles (SG-STHXs) by means of the computational fluid dynamic (CFD) method. The numerical results show that for the same mass flow rate m in the shell side, the heat transfer coefficient h, the overall pressure drop Δp, and the heat transfer coefficient per pressure drop h/Δp of the CPTP-STHX-improved are 41.1%, 34.5%, and 4.9% higher than those of the SG-STHX, respectively. For the same overall pressure drop in the shell side, the heat transfer coefficient of the CPTP-STHX-improved has 23.1% increases than that of the SG-STHX. Based on these results, it can be concluded that the CPTP-STHX-improved might be used to replace the conventional STHX with segmental baffles in industrial applications.