Experimental Investigation of the Entrainment into Diesel Spray

The mixing process of fuel with the surroundings are necessary to verify combustion process and then to make a combustion model.

In this study, a single shot of diesel spray is injected through either a constant pressure injection system or bypass type injection system which has the same characteristics as the one of an actual engine.

Measurement are made on the gas velocity distribution around the spray and its time history using a hot wire anemometer. The gas flow direction is determined by the smoke tracer method.

In this investigation the axial and radial distributions of entrainment air are determined, and also their time histories are observed. Radial distribution of the entrainment velocity can be shown

ū(t) = Cr^A

and the entrainment coefficient α_e is estimated to be a volume between 0.2 ∼ 0.3.