ID 365

Transient cavitation in transparent diesel injectors

 

Abstract:

While diesel fuel injectors with converging and hydro-eroded holes are generally known to cavitate less and have higher discharge coefficients during the steady period of injection, less is known about the flow during transients of needle opening and closing. In this study, single-hole transparent nozzles were manufactured with the same hole inlet radius and diameter as the Engine Combustion Network Spray D nozzle, mounted to a modified version of a common-rail Spray A injector body and needle. The transients of needle opening and closing were visualized with high-speed backlit microscopy at injection pressures as high as 1000 bar. Sources of cavitation were identified, which affect gas ingestion into the sac after the end of injection and disruption to the spray during next opening of the injector.