Computational Studies for the Design Parameters of Hollow Fibre Membrane Modules

In this paper, several design features of Hollow Fibre Membrane Modules have been studied using Computational Fluid Dynamics (CFD). The features studied included the combined effects of packing density, fibre length, fibre inner diameter, as well as the potting thickness, so as to analyse the corresponding changes to the local flux distribution and permeate output flowrate. Under different feed pressures, simulation results showed that the decrease in feed pressure along the membrane fibre was greatly affected by both the fibre length and packing density. In general, fibres packed at 0.5 packing density (i.e. 50% of the total space within the module is occupied by hollow fibres) had the highest permeate flow rate, and the optimum packing densities of longer fibres (Length≥1 m) were lesser than those of shorter fibres. The increase in inner diameter led to a proportional reduction in the permeate pressure, while improving the overall Transmembrane Pressure (TMP) and permeate flowrate. The inner diameter required for optimum output flowrate was dependent on the length of fibre used, in which longer fibres used required a larger inner diameter to ensure optimum output flowrate. Finally, reduction in permeate flowrate caused by potting thickness was found to be proportional to the permeate flowrate at the outlet of the hollow fibre.