Numerical investigation of the flow dynamics and heat transfer in a rectangular shell-and-tube heat exchanger

Abstract

Numerical simulations have been carried out to investigate the turbulent flows and coupled conductive/convective heat transfers in a glycol to water shell-and-tube heat exchanger (one shell, one tube doing six passes). The refrigerant (glycol) flows in the tube, and a secondary fluid (water) flows in the shell. The k-ω SST model is used to close the system of equations in the turbulent regime. The present model is first favorably compared and validated against experimental and numerical researches for a concentric annular heated pipe for two radius ratios (R∗=0.1and0.5) at a bulk Reynolds number ReDh=8900 and a Prandtl number Pr=0.71. It is then extended to consider the shell-and-tube configuration with a rectangular shell. Its thermo-hydraulic performances in the tube side are quantified for different Reynolds numbers at the cold inlet ranging from 1.03 × 103 to 1.47 × 105. The performance of the heat exchanger is then enhanced by introducing baffles in the rectangular shell. The results are finally discussed in terms of three global performance metrics.

Keywords

• RANS modeling
• Shell-and-tube heat exchanger
• Rectangular geometric shell
• Concentric annular pipe
• Baffles