Abstract
This study focusses on the influence of nozzle geometry on mixture formation and spray/wall interaction. We compare two high-pressure, multi-hole nozzles with an identical structure but different rounding radius of the orifice hole-inlet and different orifice hole-geometries with one another: Injector A with an orifice length to diameter ratio of 3/2 and Injector B with an orifice length to diameter ratio of 1/1. On the one hand, we visualized the spray formation using high-speed imaging, where we observed several differences. On the other hand, we also examined the spray/wall interaction and wall film forming by means of infrared thermography (IR). The IR measurements show that Injector B generates clear benefits while proving the positive effect of a reduced amount of wall film. This is very important for a clean combustion and a decrease in soot emissions.
KEYWORDS – nozzle geometry, spray formation, piston wetting, infrared thermography