Numerical simulation of the effect of EHD flow on corona discharge in compressed air

This paper presents the numerical study of the effect of electrohydrodynamic flow on corona discharge in a pin-plate system in compressed air (one to sixty atmospheres pressure). The coupled electric and gas flow fields were solved simultaneously by using the commercial CFD FLUENT software. A hybrid numerical algorithm based on the Boundary Element Method, the Finite Element Method and the Method of Characteristics was employed to calculate the electric conditions solving both the Poisson´s and charge transport equations. This part is coded as the User-Defined-Function in FLUENT and the gas flow simulation does not start until the calculation of the electric field is convergent. It has been shown that the ion convection effect increases with the increase of pressure. Under higher operation pressures the corona current is no longer proportional to the ion mobility and neglecting the influence of EHD flow on corona discharge may result in significant errors.