Electrospray performance of interacting multi-capillary emitters in a linear array

Here, we report electrospray performance of multiple emitters (of internal diameter 200 µm) arranged in a linear (inline) array. For a fixed flow rate Q, at higher voltages Va, multi-jet mode is observed, which leads to a rapid increase in the spray current (I∼Va) as compared to the single cone-jet case (I∼Va0.8). A theoretical model is presented that predicts (within 10% of experimental data) the divergence of sprays g(x) issued from a pair of interacting emitters due to the mutual Columbic interaction of space charges. The variation of onset voltage Vo and spray current I with spacing between the emitters p is studied and it is found that Vo∼p−0.2 and I∼p0.8. The effect of the flow rate Q, voltage V and number of emitters n on the spray current I is investigated and it is found that I∼Q0.5, I∼Va0.8 and I∼n. The present work provides insight regarding the behavior of interacting sprays in an inline configuration and could be significant in the design of multiple emitter systems for electrospray applications.