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Indexed by:Journal Papers

Date of Publication:2019-12-01

Journal:EXPERIMENTS IN FLUIDS

Included Journals:SCIE

Volume:60

Issue:12

ISSN No.:0723-4864

Abstract:The vaporization of the fuel film after spray/wall impingement dramatically affects the combustion and emission behaviors in engines. In this study, the formation and vaporization characteristics of the fuel film were investigated by injecting diesel fuel from a single-hole injector onto a high-temperature, rough wall. The film thickness was measured using the refractive index matching (RIM) technique. The influence of fuel injection duration, injection pressure, and wall temperature on the film vaporization process was discussed based on the measurements. The results indicated that when the wall temperature reached a critical value, the nucleate boiling of the fuel film appeared. The boiling intensity dramatically increased and the boiling duration decreased with the increasing wall temperature. It was also found that the boiling phenomenon of the wall film was closely associated with the thickness of the residual fuel film on the wall and the film temperature, while it was nearly independent on the fuel injection conditions. Based on the theoretical analysis, it was revealed that there was a critical bubble radius for the bubble nuclei growing in a certain thickness of the fuel film within a conical pit.