Numerical Study On Spray&Combustion Characteristic Of Marine Engine Injectors In A Constant Volume Chamber

To investigate the effect of injector parameters on spray,combustion and emissions in marine low speed large two-stroke diesel engine with heavy fuel oil(HFO),in present work an injector with five holes is used and three-dimensional simulation carried out.To study HFO characteristic,physical properties of HFO applied using an experimental data from rotational flow constant volume combustion chamber and validating it with present model.Based on the different physical properties of heavy fuel oil,the spray penetration length,evaporated fuel mass,SMD,spray plume is analysed,under different ambient pressures,ambient temperature,holes diameter variation,holes position variation,injection pressure variation and swirl condition.For a non-reacting simulation,it initiate that computed liquid penetration length is in good covenant with experiment data.The influence of swirl ratio on spray penetration length has been investigated simulation penetration are improved under swirl ratio condition,but the Penetration of one injector hole drastically decreased due to anti swirl effect.During the nozzle diameter variation from 0.675 mm to 0.875 mm,the penetration length of liquid spray reduced with decrease.For the injection pressure variation from 1000 bar to 1400 bar,the liquid spray penetration length increased with the increase in injection pressure and evaporated fuel mass and SMD increased with the increase in the injection pressure.For the variation of ambient temperature from 900 K to 1100 K,the spray penetration and evaporated fuel mass are slightly rises,with the rise in ambient temperature but it has great impact on SMD with the increase in ambient temperature.For combustion simulations,carried out in a constant volume combustion chamber using Shell/CTC combustion model.The effects oxygen concentration on the combustion and emissions of heavy oils additionally studied.Studies have shown oxygen concentrations will has a significant effect on the flame morphology and flame structure of the combustion process,which affects NOx and Soot emissions...