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

Combined parallel and serial two shell-pass shell-and-tube heat exchangers (CPTSP-STHXs & CSTSP-STHXs) whose outer shell pass are set up continuous helical baffles have been proposed to enhance the heat transfer performance. The CPTSP-STHX and CSTSP-STHX are compared with the segmental baffled shell-and-tube heat exchanger (SG-STHX) by computer simulation. The results of simulation present that, total heat transfer rate Q of the CPTSP-STHX and CSTSP-STHX-1 raise nearly 5.1% and 9.5% respectively, and the heat transfer coefficient h of the CPTSP-STHX and CSTSP-STHX-1 enhance nearly 7.6% and 14.8% than that of SG-STHX, while all of them have the same mass flow rate M, the same heat transfer area A, and the same pressure drop Δp. Also under the same mass flow rate M and the same heat transfer area A, the Q and the Δp of the CSTSP-STHX-2 increase nearly by 46.3% and 130.9% than those of the SG-STHX, respectively. As to the comprehensive performance, under the same heat transfer area A and overall pressure drop Δp, the heat transfer coefficient h of the CPTSP-STHX, CSTSP-STHX-1 and CSTSP-STHX-2 raise nearly 7.6%, 14.8% and 31.2% respectively compared with the SG-STHX. Thereby the CPTSP-STHX and CSTSP-STHX have better comprehensive performance than that of SG-STHX, and furthermore the CSTSP-STHX is the best one among three.