Numerical simulation of the deposition pattern in multiple electrohydrodynamic spraying

Abstract

The numerical simulation of a deposition pattern produced by multiple electrohydrodynamic spraying with a capillary-extractor-substrate configuration was investigated using a three-dimensional Lagrangian model. The variables that controlled the characteristics of the deposition pattern were the extractor-substrate voltage, the moving speed of nozzles, and the distance between the nozzles. The deposition characteristics, including the spatial distribution and the average thickness distribution, Varied considerably as a function of these factors. In particular, the thickness and uniformity of the intervening region of adjacent sprays are important characteristics that affect the nature of the deposition that results from this technique. The results of the numerical simulation of this study show that the thickness of the intervening region gradually decreases compared with the core region of the sprays when the extractor-substrate voltage or the distance between the nozzles increases. As the moving speed of nozzles increases, the average thickness of the deposition pattern decreases. However. the uniformity of the thickness in the intervening region, as well as the extent of the coverage of the deposition, is maintained despite increases in moving speed of nozzles. It is suggested that the electrical self-dispersion effect and the electrical repulsive interaction between adjacent sprays play an important role in determining the characteristics of the spray evolution and deposition patterns for Multiple electrohydrodynamic spraying. In addition, an understanding of multiple electrohydrodynamic spraying, as controlled by the factors mentioned above, can improve the prediction of its deposition characteristics. (C) 2009 Elsevier B.V. All rights reserved.