Atomization and combustion of a simple electrospray

A simple atomizing device is presented capable of generating controlled spray by using an electric field either in isothermal and burning conditions. The stability operating range of controlling parameters (e.g. liquid flow rate and applied voltage) is determined. The coupling of atomization and combustion processes is analyzed by measuring, using a PDA system, the drop diameter distribution as well as the radial and axial components of drop velocities. Preliminarily the influence of controlling parameters on the droplet size is presented and discussed. The spray structure as well as its evolution in space and time is presented in selected conditions, chosen on the ground of the preliminary analysis. The presence of the flame affects significantly the spray shape and the droplet dimensions. This effect is particularly relevant in the higher liquid flow rate case. A deeper analysis of the measurements allow for the determination of relative importance of different physical effects in the different conditions. The final conclusions of the paper is that the coupling between atomization and combustion processes can be hardly forecasted without a thorough analysis of the spray characteristics in the specific working condition. This poses a severe challenge for the practical application of these atomizing system for the set-up of effective combustion controlling systems that want take advantage of electric field modulation.