Numerical study on ion conduction-induced electro-thermo-convection in a square cavity

Abstract

This paper presents a numerical study of electro-thermo-convection (ETC) in dielectric liquid within a square cavity, incorporating electric conduction modeling to investigate flow characteristics under the influence of electric field and Rayleigh number. The governing equations of electro-thermo-hydrodynamic (ETHD) are solved using finite volume method. Compared to natural convection, ETC exhibits significant changes in both flow structure and intensity. The critical Rayleigh number for the onset of ETC in this study is about 6500. As Rayleigh number increases, the ETHD system transitions from static state to steady flow, then to stable periodic flow, ultimately reaching quasi-periodic flow. The critical Rayleigh number for the transition from steady to periodic flow is around 31,750. During this transition, the system sequentially loses its left–right and up–down symmetries, with the loss of up–down symmetry leading to a reduction in oscillation amplitude. Additionally, within a certain range, the flow intensity exhibits an approximately linear relationship with the Rayleigh number.