Flow enhancement strategies and hydrodynamic analysis in hollow fiber modules for membrane distillation applications

摘要: Low-field bench-top nuclear magnetic resonance imaging (MRI) has been applied to investigate the hydrodynamics and flow distributions in novel hollow fiber modules designed for membrane distillation (MD) process. For this purpose, pulse field gradient (PFG) technique was acquire fluid displacement probability distribution (propagator) information inside module. Velocity mapped using a combined MRI PFG method. As an extension of our prior MD module study, dynamics performance four representative configurations (i.e., with randomly-packed fibers, spacer-knitted curly semi-curly fibers) were investigated terms cross-section imaging, diffusion propagator experiments, velocity maps shell-side flow. The results showed that compared (as benchmark), configuration fibers had narrower propagators bulk direction, higher water molecules large Y (parallel-to-flow) more intense local mixing homogeneity revealed through standard deviation calculation, which corresponded well enhanced performance. On contrary, as well-performed evaluated process tests, interesting ―channeling‖ phenomena via NMR at relatively high rate. Fortunately, able provide comprehensive understand unusual behaviors such complex channel.