Coupled heat and mass transfer of cross-flow random hollow fiber membrane tube bundle used for seawater desalination

Abstract

Fluid flow and coupled heat and mass transfer of a cross-flow random hollow fiber membrane tube bundle (RHFMTB) used for seawater desalination are numerically studied. The fiber tubes are in random distribution in the fiber bundle, and the physic-mathematical model is established for fluid flow, temperature and humidity fields. The influences of fiber distribution feature, packing fraction and Reynolds number on the thermo-humid-fluid performance of the fiber bundle are investigated. In order to quantitatively analyze the distributed features of RHFMTB, the Delaunay subdivision of the cross section is used. It is found that the cut-through cavities which are defined as the void spaces around the fiber bundle have significant effect on the air flow distribution, and further impact on the heat and mass transfer performance. The packing fraction is also an important parameter and the Nusselt number, Sherwood number and friction factor are obtained with various packing fractions. The results show that the friction factor has an explosive growth with high packing fraction due to the easily formed narrow flow channels. At last, the performances of fiber bundle with different arrangements are compared. The friction factor with random arrangement is the maximum, especially with high packing fraction.