A correlation image velocimetry-based study of high-pressure fuel spray tip evolution

A correlation image velocimetry (CIV) technique has been developed to study the evolution of the leading edge, or tip, of isothermal high-pressure fuel sprays. Adaptations of the analysis permit determination of both the average spray tip motion and the spatial distribution of velocity along the spray edge. From these measurements, three distinct regions of the tip's evolution have been observed and scaling relations developed. Further investigation has revealed significant uniformity in the radial evolution of the spray tip, despite the apparent similarity to turbulent jet flow. Examination of pdfs of the average tip velocity reveals among the many repeatable injection events a significant amount of variability and that this variability extends to regions near the nozzle, implying that among the sources of shot-to-shot viability is the atomisation process itself.