Experimental and numerical analyses of electrohydrodynamic force according to air pressure


 Electrohydrodynamic (EHD) force induced by corona discharge has been suggested as a new thrust for solar planes and stratosphere balloons in near space. However, its performance at low air pressures remains to be clarified. An experiment to measure the EHD force at pressures of 0.02～1.0 atm has been carried out with the wire-to-cylinder geometry. The drift-diffusion model with two-dimensional numerical simulation is used to analyze the ions’ distribution. The experiment result shows that the EHD force is not linearly related to the corona discharge current at low air pressures. Numerical simulation finds that the proportion of ions in the counter-direction electric field increases from approximately 0.36% to 30% when the pressure drops from 1.0 to 0.2 atm. As a result, the EHD force with a constant power supply drops faster than the previous theoretical prediction in the ground experiment. It suggests that the consideration of counter-direction EHD force is necessary to improve the ionic wind propulsion efficiency in near-space applications.