3-D numerical investigation on commercial PTFE membranes for membrane distillation: Effect of inlet conditions on heat and mass transfer

Abstract

Computational fluid dynamics (CFD) techniques were implemented to develop a 3-D numerical model to investigate the effect of several inlet conditions on the heat and mass transfer through a commercial PTFE membrane in a specific direct contact membrane distillation (DCMD) cell design. The model was validated against other researchers’ results and was found to have a good arrangement. The model was then used to predict the effects of changing the direction of the flow, inlet Reynolds number and feed inlet temperature on the permeate flux through the membrane and the process thermal efficiency. It has been found that changing the flow arrangement from parallel to counter flow slightly increased the permeate flux. Changing the inlet Reynolds number from 25 to 50 significantly increased the permeate flux and the process thermal efficiency, while raising it from 50 to 150 had little to no effect. It has also been found that increasing the feed inlet temperature from 303 K to 323 K almost tripled the permeate flux. Keywords: Membrane distillation, Direct contact, Desalination, Modeling, CFD, PTFE, Polymers