NUMERICAL INVESTIGATION OF COMBINED PARALLEL TWO SHELL-PASS SHELL-AND-TUBE HEAT EXCHANGERS WITH CONTINUOUS HELICAL BAFFLES

摘要

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 Delta p, and the heat transfer coefficient per pressure drop h/Delta p 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.