Photographic Study of Spray Impinging onto a Projection on a Wall

As a fundamental work on Direct Injection Impinging Diffusion Combustion Engine, fuel spray was injected momentary into a pressured CO₂ gas and impinged onto a projection on a wall. Instantaneous photograph was taken and analyzed to clarify the spray characteristics. Nozzle opening pressure was varied to clarify its effects on spray characteristics. Nozzle needle was cut to form two pairs of flats on needle surface instead of its cylindrical one. The effect of this needle shape was also studied.

Opening pressure of injection nozzle has produced very little effect on the spray tip penetration. Spray thickness is larger when needle opening pressure of injection nozzle is high.

Spray tip penetration and spray thickness have become large when widths across flats is narrow.