非定常噴霧火炎の流れ特性に関する実験的研究

抄録

In diesel engines, mixture formation of fuel and air is closely related to the formation of a spray flame. The relationship of the behavior between an evaporated fuel spray and a spray flame needs to be clarified for further improvement of thermal efficiency in the diesel engine. However, it is difficult to measure the in-plane velocity field of a spray flame using the PIV method because it is impossible to separate the scattered light from the tracer particles and the luminous flame. In this study, the flow characteristics of an unsteady spray flame were experimentally investigated by obtaining the velocity field inside its flame with typical PIV. Oxygenated fuel was used as test fuel in order to suppress the light intensity from the luminous flame. The velocity field of the spray flame was compared with that of the evaporated spray. As the results, the axial velocity of the spray flame was higher than that of the evaporated spray. Furthermore, the normalized turbulent intensity of the spray flame regardless of the position in the flow direction and the injection pressure was smaller than that of the turbulent jet.