Energetic aspects of turbulence promotion applied to electrolysis processes

Abstract

This paper presents a simple and rational method for determining how much hydrodynamic factors influence the rate of production in electrochemical systems using turbulence promoters in various alternative flow conditions. Empirical and theoretical data correlations of limiting current densities (or mass transfer coefficients) and pressure drops are presented in unobstructed channels as well as for eddying flow induced by different types of eddy promoters. Based on the dimensional analysis and on the experimental results, it is shown that, within a given range of variations, all the promoters have an equivalent energetic effectiveness. However, when the conversion factor of the reacting species through the electrochemical reactor is near unity (complete transformation), this conclusion is no longer valid and the general methodology presented in this work shows that the rates of production present large differences depending on the system considered, the less sophisticated system (unobstructed channel) being the most effective.

Investigation into the effectiveness of feed spacer configurations for reverse osmosis membrane modules using Computational Fluid Dynamics

“…SPC represents the mechanical energy required to overcome the fluid's pressure drop per unit length of the domain [39]. Storck and Hutin [40] define SPC as…”

Optimization of commercial net spacers in spiral wound membrane modules

“…where P is the pressure drop over the channel, L is the channel length, A is the cross-section area of the channel, and u is the mean liquid velocity in the channel. A similar approach was described by Storck and Hutin [19] in which results were presented in the plots of k m versus SPC.…”

Simulation of the Flow around Spacer Filaments between Channel Walls. 2. Mass-Transfer Enhancement

“…[1][2][3][4] A number of researchers examined experimentally the effect of flow, which is obstructed by filaments, in electrochemical cells. [5][6][7][8][9][10][11][12][13] The filaments increased both the local and the overall mass-transfer rate. The results showed that high wall shear stresses and the reattachment regions of recirculation zones increase the local mass-transfer rate.…”

“…Spacer nets are used in spiral-wound membrane modules to keep the membrane leaves apart and to reduce the wall concentration by enhancing the mass transfer. − A number of researchers examined experimentally the effect of flow, which is obstructed by filaments, in electrochemical cells. − The filaments increased both the local and the overall mass-transfer rate. The results showed that high wall shear stresses and the reattachment regions of recirculation zones increase the local mass-transfer rate.…”