Use of numerical modelling to assess the influence of the electrostatic configuration on the electric field in an electrospray thruster

The use of electric propulsion systems is increasing and is operational in more than 300 active spacecraft. The present study uses a 2D axisymmetric model to numerically investigate the electric field within an electrospray thruster by considering different emitter geometries and varying extractor placement relative to the emitter. The electrohydrodynamics model in OpenFOAM has been used. The electric potential contours for the hole emitter geometry varied substantially compared to other geometries that showed similar contour pattern. Using identical fixed input settings for each emitter design, matching cone-jet profiles were observed with variation only for hole shape emitter where the cone base commenced much further back against other emitter designs due to the highest peak field strength outputted at the edge of the hole emitter. Altering the emitter and extractor distance influenced the electric potential contours while electric potential remained constant but showed negligible effect on the axial velocity.