Optical fuel spray characterization of hydrotreated vegetable oil (HVO) and ethanol

Abstract

The global concern about climate change has remarkably increased because of its tangible environmental effects. Transportation being one of the major contributors to greenhouse gas emissions is taking a substantial part in global warming and climate change. Fortunately, the shift of emerging transportation technology towards electric power sources has proven to be a favorable solution towards sustainable and cleaner transportation addressing global climate change. However, some constraints related to battery technologies and charging infrastructure created a necessity of research towards alternative cleaner fuels for internal combustion engines. Ethanol is one of the alternative fuel that has caught much attention because of its remarkably low emissions.

The experimental study in this thesis investigated the comparison of HVO and ethanol with EN590 diesel fuel sprays in terms of overall spray geometry and droplet size measurements by analyzing the monochrome spray images. The fuel sprays were injected using two different fuel injectors with different nozzle orifice diameters into a constant volume chamber at varying conditions of injection pressure and gas density.

In terms of overall spray geometry and droplet size measurements, HVO and EN590 diesel sprays showed quite similar trends, however, significant differences could be observed for ethanol sprays. Ethanol sprays were characterized with lower penetration, larger opening angles and smaller droplet sizes than HVO and EN590 sprays. A Significant decrease in mean diameters and droplet size distributions could be identified by increasing the injection pressures. Furthermore, the results for the injector with increased nozzle orifice diameter compared with the reference nozzle suggested decrement in spray penetration and increased opening angles for EN590 fuel sprays.