Experimental study on fuel drop impacts onto rigid surfaces: Morphological comparisons, disintegration limits and secondary atomization

This paper addresses an experimental study of the effects of the topography of surfaces impacted by fuel sprays on the process of fuel–air mixing in internal combustion engines. The experiments reported here consider the use of a simplified flow configuration consisting of individual droplets impacting onto flat surfaces with different surface topographies, roughness and temperatures. The main parameters which were systematically varied are surface wettability and topography and liquid viscosity. The analysis considers the onset of splash, which involves the identification and characterization of different disintegration mechanisms. The characterization is performed in terms of crown morphology, temporal evolution and secondary droplet characteristics, for different boiling regimes. The results are interpreted to better understand the influence of the nature of the surface in the efficiency of the disintegration mechanisms.