The combustion process of a diesel engine is mainly determined by the fuel-air mixing characteristics. In order to study the effect of injection pressure and ambient pressure on jatropha oil fuel-air mixing characteristics in diesel engine. In this paper, based on the open source finite element software OpenFOAM, a new spray model was established, which considered the effect of fuel evaporation on the spray, and the model has been verified by experimental results. We analyzed the fuel-air mixing characteristics of Jatropha oil spray used this model. The result show, changing injection pressure and ambient pressure can improve jatropha oil fuel-air mixing characteristics, As the injection pressure increases and the ambient pressure decreases, the spray breakup velocity gradually decreased and finally tends to a constant, spray volume increased dramatically, a small increase in spray air entrainment and spray equivalent ratio unchanged at early and late stage, greater reduction in the middle. Therefore, we can award good fuel-air mixing characteristics of jatropha oil by increasing the injection pressure and reduce the back pressure.
Fuel-air mixing characteristics, Jatropha oil, Air entrainment, Diesel engine.
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