However, in the case of pattern C, the fuel injection velocity increases with time and succeeding fuel droplets often catch up with and move past proceeding fuel droplets, resulting in the higher fuel concentration around the spray tip. The temporal evolution of the spray flame is shown in Figs. 8 (a) and (b). In these graphs, the temporal changes of the luminous flame area, which is indicated between the lines of the flame tip and bottom in the graphs, are compared with the temporal change of the spray tip penetration for the experiment on non-evaporating spray under same ambient density. From Fig.8 (a), in the case of pattern A, it can be seen that the combustion started between 20 to 30 mm downward from the nozzle with the ignition delay of 0.63 ms.
Figure 3 Photographs of non-evaporating spray under air pressure of 1.09 MPa and at room temperature; frame interval of (a) is 0.25 ms and that of (b) is 0.5 ms.
Figure 4 Experimental results of spray tip penetration for Pattern A, B, and C under air pressure of 1.09 MPa and at room temperature
Figure 5 Calculated results of spray tip penetration for Pattern A, B, and C under air pressure of 1.09 MPa and at room temperature
