The influence of cavitation on the internal flow and the spray characteristics in diesel injection nozzles

Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics

A basis for the comparison of various experimental methods for studying spray penetration.

Diesel fuel injector nozzles have a significant effect on the quality of spray and charge preparation. However, the mechanism and degree of this effect is unclear. The complexity of the internal nozzle flow has hindered the study of the fuel injection process. Diesel fuel injector nozzle flows are highly turbulent and usually two-phase. Several experiments have shown the presence of cavitation in the nozzles to be a dominating effect. Recent experimental work has revealed new qualitative details about the cavitation in fuel injector nozzles. The cavity tends to be smooth near the inlet, transitioning to a more ruffled appearance downstream. These flows are also strongly asymmetric in realistic geometries. Additionally, photographs have shown string cavitation inside the sac volume extending into the nozzles. The strings appear to be a form of stratified two-phase flow, like the cavities near the inlet corner. Like the cavities, the strings break down into bubbly flow near the exit of the nozzle. F...

The internal flow of diesel fuel injector nozzles: A review:

Modeling the Effects of Injector Nozzle Geometry on Diesel Sprays

The results of a number of previous investigations of the discharge characteristics of parallel-bore orifices with length/diameter ratios up to 10 and Reynolds numbers up to about 105are collected ...

A. Lichtarowicz

Papers

Discharge Coefficients for Incompressible Non-Cavitating Flow through Long Orifices