Numerical study on the effect of EHD flow on mass transfer of gas mixtures

Abstract

Purpose The paper aims to discuss the mass transfer of gas mixtures under the influence of electrohydrodynamic (EHD) flow induced by direct current (DC) corona discharge of wire-to-plane electrode, using a coupled numerical model. Design/methodology/approach A coupled numerical method is developed in this paper. Lattice Boltzmann model of binary gas mixtures coupled with the Coulomb force as an external force is introduced to predict the gas flow and species transport affected by EHD flow. Meanwhile, the distributions of electric field and space charge density during DC corona discharge are obtained using the finite difference method and the method of characteristics. Findings The numerical results of mass transfer effected by EHD flow reveal that the high electric field intensity is observed near the surface of corona wire, which causes the higher Coulomb force to form the EHD flow pattern of anticlockwise vortex. The EHD vortex flow plays a considerable role in the mass transport enhancement of gas species emit from the plane electrode, and the significant difference of the local Sherwood number is presented along the direction parallel to plane electrode. In addition, the enhance effectiveness with the different applied voltage is assessed, and the influencing mechanism of enhancement is investigated in this work. Originality/value The proposed numerical model will be useful in the study of mass transfer and fluid flow effected by EHD.