Effects of sealing strips on shell-side flow and heat transfer performance of a heat exchanger with helical baffles

Abstract

In the present paper, numerical simulations are carried out to investigate the effects of number and width of the sealing strips on shell-side flow and heat transfer of a shell-and-tube heat exchanger (STHX) with helical baffles. Based on the periodic model, the STHX with discontinuous helical baffles (DCH-STHX) and the STHX with continuous helical baffles (CH-STHX) are investigated under the same helix angle 40° which is the optimal angle proved by the previous research studies. The 320# conductive oil is selected as the working fluid. The results show that under the same mass flow rate M and the width of the sealing strips W, with the increase of the number of sealing strip, the shell side Nusselt number is 9.3–41.7% higher than that without sealing strips while the resistance increases by 37.5–189.7%. Four uniformly distributed sealing strips is the optimal structure. Under the same mass flow rate M and the number of sealing strip, with the increase of the width of the sealing strips W, the Nusselt number increases by 1.6–34.5% while the resistance increases by 11.1–146.6%. The larger width of sealing strips, the better heat transfer performance. However, the comprehensive performance j/f decreases with increasing in width and the number of the sealing strips. The numerical simulation results also show that the sealing strips are more effective to improve the heat transfer performance of the CH-STHX than that of the DCH-STHX, especially in the cases of large mass flow rate.