Micale G

CFD modelling of profiled-membrane channels for reverse electrodialysis

AbstractReverse electrodialysis (RE) is a promising technology for electric power generation from controlled mixing of two differently concentrated salt solutions, where ion-exchange membranes are adopted for the generation of ionic currents within the system. Channel geometry strongly influences fluid flow and thus crucial phenomena such as pressure drop and concentration polarization. Profiled membranes are an alternative to the more commonly adopted net spacers and offer a number of advantages: avoiding the use of non-conductive and relatively expensive materials, reducing hydraulic losses and increasing the active membrane area. In this work, Computational Fluid Dynamic simulations were performed to predict the fluid flow and mass transfer behaviour in channels with profiled membranes for RE applications. In particular, channels equipped with pillars were simulated. The influence of channel geometry on fluid flow and concentration polarization was assessed by means of a parametric analysis for differe...

Digital image analysis technique for mixing pattern measurements in Bi-dispersed 2D gas fluidized beds

This work concerns a new experimental technique based on Digital Image Analysis for the measurement of the mixing behaviour in a bi-dispersed 2D fluidized bed. Two different sets of particles are fluidized with the same density and different size. The technique is based on suitable color-field decomposition of the fluidized bed snapshots, where particles of different colors are employed. The technique here proposed can effectively measure the concentration field in the whole bed during operation and capture the mixing and segregation dynamics of powders. Notably, the technique here developed can be used for both gasor liquidfluidized beds.