0000000000726492
AUTHOR
Francesco Nicolò Ponzio
Unsteadiness and transition to turbulence in woven spacer filled channels for Membrane Distillation
To characterize the performance of Membrane Distillation (MD) modules, channels filled with woven spacers were investigated by Computational Fluid Dynamics (including Direct Numerical Simulations and the use of the SST k-Ï turbulence model) and by parallel experiments with Thermochromic Liquid Crystals. The cases considered here regard mutually orthogonal filaments with a spacer pitch to channel height ratio P/H=2, two spacer orientations θ with respect to the main flow (0° and 45°), and bulk Reynolds numbers Re from â¼200 to â¼2000, an interval of great interest in practical MD applications. For both values of θ, CFD predicted steady-state flow for Re up to â¼300, and chaotic flow …
Experimental and computational investigation of heat transfer in channels filled by woven spacers
Abstract Models of woven-type spacer-filled channels were investigated by Computational Fluid Dynamics (CFD) and parallel experiments in order to characterize the performance of Membrane Distillation (MD) modules. The case of overlapped spacers was analysed in a companion paper. Experiments were based on a non-intrusive technique using Thermochromic Liquid Crystals (TLC) and digital image processing, and provided the distribution of the local convective heat transfer coefficient on a thermally active wall. CFD simulations ranged from steady-state conditions to unsteady and early turbulent flow, covering a Reynolds number interval of great practical interest in real MD applications. A specif…