RT Journal Article
ID 76acd89c79964a98
A1 Pratama, Raditya Hendra
A1 Sou, Akira
A1 Katsui, Tokihiro 
A1 Nishio, Shigeru
T1 STRING CAVITATION IN A FUEL INJECTOR
JF Atomization and Sprays
JO AAS
YR 2017
FD 2017-03-07
VO 27
IS 3
SP 189
OP 205
K1 string cavitation
K1 diesel fuel injector
K1 visualization
K1 lateral inflow
AB In a nozzle hole of a diesel fuel injector, string cavitation may appear along the nozzle-hole axis which affects the fuel
spray characteristics. Previous studies concluded that string cavitation is the result of the complex swirling flow in the
upstream region. However, the mechanism of the swirling flow formation, the condition of string cavitation appearance,
and its effects on the injected liquid jet are not well understood. In this study, visualization of cavitation in a cylindrical nozzle hole with an asymmetric inflow from various simple rectangular upstream channels was conducted. The effects
of needle lift and the number of nozzle holes were examined by changing the height and the width of the upstream
channel, respectively. High-speed images of string cavitation formation were captured. A simple numerical simulation
was carried out to qualitatively examine the velocity and pressure distributions. As a result, we clarify the condition
of string cavitation formation and propose the string cavitation regime maps which take dimensionless needle lift and
liquid velocity as major parameters. We find that string cavitation and a resulting swirling hollow-cone liquid skirt
are formed at low needle lift and high liquid velocity, while at high needle lift no string cavitation is formed. Under the
narrower upstream channel width condition, which represents a fuel injector with many nozzle holes, string cavitation
occurs only at much lower needle lift and higher liquid velocity. The numerical results show a good agreement with
the experiment results; i.e., a slanted swirling inflow with low pressure along its axis is formed in the nozzle hole only
under the low needle lift condition.

PB Begell House
LK https://www.dl.begellhouse.com/journals/6a7c7e10642258cc,3959832a022ff403,76acd89c79964a98.html