Physical modifications for improving inlet flow distribution evenness in multiple parallel-arrayed membrane modules

Abstract

This study was conducted to validate a proposed hydraulic modification for improving the evenness of the inlet flow distribution in a manifold pipe in a water treatment system in which the treated water flows in parallelly arranged membrane modules, by performing computational fluid dynamics (CFD) simulations and experiments. The results of the CFD simulations confirmed that the coefficient of variation of the flow rate distribution in the manifold pipe could be reduced by approximately 47% by installing an inner orifice pipe within the header pipe (double header pipe). In addition, the experimental results showed that the coefficient of variation was reduced by 67% for a double header pipe compared with a single header pipe. Furthermore, when the diameter of the inner orifice pipe was identical to that of the branch pipe connected to the external header pipe, the flow distribution evenness was maximized.