Experiment And Simulation Of Fluid Dynamics And Mass Transfer In An Electrochemical Oxidation Reactor

Environmental problems are increasingly highlighted by industrial organic wastewater,and electro-catalytic oxidation technology as an effective Advanced Oxidation Process of treatment has been the focus of environmental technology research.Based on the P-Methoxyphenol?PMP?as a model pollutant,the bubble effect,fluid dynamics and mass transfer behavior in the electrochemical oxidation were studied by Computational Fluid Dynamics?CFD?,which provides a theoretical basis for the reactor design and the operation condition selection.This paper studied PMP degradation process by ultraviolet absorption spectroscopy,combined with the related literature of apparent degradation kinetics,heterogeneous phase rate constant k_app and the adsorption desorption equilibrium constant K have been obtained by the nonlinear fitting.In addition,the 4-5 min process of degradation reaction was recorded by high speed camera.The photograph of motion behavior of the bubble curtains on the anode surface was analyzed.The bubble size information was counted by ImageJ,and the average diameter of the bubble was 0.125mm.The surface gas fraction of electro-oxidation area was obtained by Photoshop and MATLAB.Combined with the theory of depth of field,gas volume fraction was obtained from surface gas fraction,and compared with the simulation results,the experimental and simulation results are consistent,the comparison show that the correctness of the mathematical model for numerical simulation.The Eulerian-Eulerian method was used to describe two-phase bubbly flow of the degradation process in the numerical simulation.In order to accurately predict the bubbly flow,the bubble size effect has been considered by interfacial area concentration model,and the results of the constant size bubble and variable size bubble show that bubble size has important influence on gas bubble movement.The influence of flow velocity,the distribution of PMP concentration and gas fraction distribution on fluid dynamics were simulated in the research,the results indicate the electrochemical cell exist the retention area,bubble layer have larger resistance effect on the distribution of PMP.Compared with other conditions,the electrode gap have a great effect on the fluid dynamics and distribution of PMP.According to the viewpoint of reducing the bubble effect,the optimum operation condition for I=45 A/m²,u_in=0.07 m/s,?=8 mm.Through analyzing the contours of Sherwood number on the anode surface under different conditions,the results show that electrochemical reaction and bubble effect play an important role in the mass transfer on the anode surface,and the mass transfer region is mostly in the mass transfer efficiency of 28-50%.