Experimental characterization of closely coupled split isooctane sprays under flash boiling conditions

The characteristics of isooctane spray in the near field and far field were experimentally studied under various flash boiling conditions representing both low load and high load hot engine operation conditions. Closely coupled split injection strategy was also employed to study the influence of flash boiling on the primary breakup of split injections and the interaction between split injections. It was found that flash boiling considerably boosted the spray atomization, especially during the end of injection stage when a large amount of liquid fuel with low speed was observed. The interaction between split injections in liquid phase was significantly weakened under flash boiling condition due to the enhanced atomization but the interaction in gaseous phase was boosted because of the resultant quicker evaporation. The effect of dwell interval on the spray behavior under flash boiling condition was profound, causing significant variation for the delivered fuel mass and spray characteristics.