Fluid flow and heat transfer across a curved hollow fiber membrane tube bank (CHFMTB): Effects of the tube deformations

- A cross-flow hollow fiber membrane tube bank (HFMTB) is employed.
- A curved hollow fiber membrane tube bank (CHFMTB) is formed.
- Fluid flow and heat transfer across the CHFMTB for air humidification/dehumidification are studied.
- The fundamental data for the staggered arrangement are larger than those for the in-line arrangement.
- The fundamental data for the HFMTB are somewhat larger than those for the CHFMTB.

A cross-flow hollow fiber membrane tube bank (HFMTB) is commonly employed for air humidification or dehumidification. The tubes in the HFMTB are easily deformed due to the gravity of the water/liquid desiccant stream inside the tubes and the scour of the air stream flowing across the tube bank. Fluid flow and heat transfer across a curved hollow fiber membrane tube bank (CHFMTB) with a regularly populated arrangement are investigated. Two unit cells containing two columns of the curved tubes are selected as the computational domains, which include 12 tubes both for the in-line and staggered arrangements. The equations governing the fluid flow and heat transfer are established via a renormalization group k-ε (RNG KE) turbulent model. The mean friction factors (fm) and Nusselt numbers (Num) for the air flowing across the CHFMTB under various tube arrangements (in-line, staggered), Reynolds numbers (Re), tube deformed heights (Δh) and angles (θ) are calculated and analyzed. It can be found that the mean friction factors and Nusselt numbers for the staggered arrangement are about 2.1-2.7 and 1.4-2.2 times of those for the in-line arrangement, respectively. For most of the Reynolds numbers ranging from 68.42 to 342.30, both the mean friction factors and Nusselt numbers for the HFMTB are almost larger than those for the CHFMTB. Further, the larger the Reynolds numbers are, the larger the differences are.