Estudo do comportamento de spray diesel em injeção direta através de modelos macroscópicos

Abstract

The main objective of this paper is to analyze the robustness of one and two zones macroscopic models for diesel engine spray penetration and angle. The analysis was performed comparing models and published literature experimental results. The experimental data obtained ranged a wide variety of fuels (such as pure mineral diesel, biodiesel of many origin as well as some single component fuels) at various injection and ambient pressures, so that the robustness could be analyzed at different input conditions. Based on the experimental data, the model from Hiroyasu and Arai (1990) presented the best results, basing robustness on the ability to produce good R² consistently for all the experimental conditions for spray penetration prediction. It was also observed that the results of this model were able to predict the progression of spray penetration for several experimental conditions, mainly during the intermediate stages of the injection process. This model also presented the best results while using pure methyl oleate and mineral diesel. The second model in terms of robustness was the one of Dent (1971), followed by the one of Bahl et al. (2016). The least robust of the four studied models was the one of Kegl and Lešnik (2018). The poor quality of the results can be explained by the use of the injection pressure. In regard to the spray angle, it was concluded that none of the models are genuinely robust. Some spray angle models were able to show good results for certain experimental conditions, but none of them were able to consistently show good results for all experimental conditions. For future works, it’s suggested an analysis using various injection nozzles and fuels, while varying the ambient temperature as well as the pressures used. It is also recommended to use own experiments as that would make it possible to use more models since it would be possible to obtain the parameters used in them. Using own experiments would also reduce the amount of external factors.