Numerical and experimental investigation to determine the optimal configuration of an aeration component in the hollow fiber membrane cleaning process

Abstract

In this study an aeration component with an optimal hole arrangement was established for air scouring of a cylindrical hollow fiber membrane module. The effects of the aeration hole arrangement on the flow field in the internal space of the membrane module were investigated using computational fluid dynamics (CFD). The effects of the aeration hole design index (γ), namely, the ratio of the distance between the aeration hole and the vertical center axis of the module (r) to the membrane module radius (R) on the liquid velocity and shear stress on the membrane surface were assessed. Different aeration hole design indexes were employed in the study. The results of CFD simulation and experimental work both indicated that the best hydraulic performance was achieved at γ = 0.75, under the conditions of which the highest liquid velocity and strongest shear stress on the membrane surface were obtained as well as the more uniform distribution of them than others. Furthermore, membrane filtration and cleaning tests were conducted to evaluate the performances of different aeration hole design indexes, which showed the superiority of the configuration of γ = 0.75 with the transmembrane pressure (TMP) recovery of 88.51%. The index (γ) can provide guidance for the configuration optimization of the aeration component for better membrane fouling mitigation and a lower operating cost.