2-D electrohydrodynamic simulations towards zero offset voltage with corona ionisers

This paper reports results from a computational investigation of charge neutralisation with DC, AC, and pulse-DC corona ionisers using 2-D axisymmetric electrohydrodynamic modelling with an emphasis on minimising the offset voltage. The results showed that balanced DC ionisers can effectively neutralise the charge of a conductive plate; however, balanced AC and pulse-DC ionisers give rise to a certain offset voltage with an oscillation caused by alternate mono-polar space charges created near the ionisers resulting from ions emitted from the ionisers. In addition, we suggest a modification for AC and pulse-DC ionisers to minimise the offset voltage, including its AC component. Consequently, we found that continuously balanced ions emitted from ionisers which can create a quasi-neutralised charge distribution by positive and negative ions in the entire space at a steady state are of significant importance to make the offset voltage zero.

► A 2-D electrohydrodynamic model for charge neutralisation has been developed.
► We investigate the charge neutralisation by ionisers to minimise the offset voltage.
► Quasi-neutralised ion distributions in the entire space make the offset voltage zero.
► Emitting continuously balanced ions from ionisers can create such distributions.
► A modification for AC and pulse-DC ionisers is proposed.