FUEL DROP SPREADING ON A FLAT SMOOTH SURFACE: NUMERICAL SIMULATIONS WITH A VOF METHOD

With the current interest in bio-derived and blended transportation fuels, the impact of the variable viscosity in these fuels on spray and splash properties has become an area of concern. In this work, the dynamics of a liquid drop impacting and spreading on a flat, smooth surface was computationally investigated by employing the volume of fluid (VOF) approach with the commercial solver Fluent 12.0.16, and the results were base-lined with experimental measurements. Of particular interest was the degree of fidelity required of the contact angle model, with the present work proposing and testing a combined static contact angle-dynamic contact angle (SCA-DCA) model to describe drop spreading. This model was shown to reduce the behavior information required as compared with full dynamic contact angle (DCA) models while significantly improving over the accuracy of a pure static contact angle (SCA) model. Two different computational domains were tested and compared for the proposed SCA-DCA model, a quarter-drop versus a full-drop domain, with the results showing that the error was reduced when the full domain was employed.