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The interference effect on an array of electrospray emitters is analytically and experimentally investigated. An analytical model is presented to predict the behavior of the operating voltage with respect to emitter spacing in an array of emitters. The basic idea of these models is to superimpose the electric potential of individual emitters together in an array of emitters. If only one of the emitters operates and no liquid is supplied through the neighboring emitters, the potential required to form a stable cone-jet generally increases as the emitters move closer to each other due to electrical shielding. However, at very close spacing the required potential decreases. If all the emitters operate simultaneously, the operating voltage required for cone-jet spraying increases as the emitter spacing decreases; furthermore, there is no decrease in potential when the spacing is very close. The results of the analytical electrostatic interference model agree well with the experimental data.

This paper presents numerical quasi-static simulation results of air entrainment phenomenon between a web and a spirally grooved roller. The numerical result shows that during one circle rotation of spirally grooved roller, traction coefficient between the web and roller is changed according to time due to changing shape of groove in contact region and average traction coefficient of spirally grooved roller is higher than circumferential grooved roller. Using laser sensor, web deflection is measured and compared with the numerical results of web deflection at the entrance region. Furthermore, smoke wire experiment shows a clear view of air entrainment phenomenon at the entrance region between the web and roller.