Aj. Yule et Dg. Salters, ON THE DISTANCE REQUIRED TO ATOMIZE DIESEL SPRAYS INJECTED FROM ORIFICE-TYPE NOZZLES, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNALOF AUTOMOBILE ENGINEERING, 209(3), 1995, pp. 217-226
Conductivity probe measurements, using ranges of nozzles, liquid prope
rties and gas densities, have revealed more extensive and reliable inf
ormation on the break-up process of diesel sprays than has been publis
hed to date. The spray generated from a single-hole orifice-type nozzl
e has an incompletely atomized break-up length which typically extends
at least 100 hole diameters downstream. The physical structure of thi
s break-up zone varies, depending on the liquid properties and both in
itial and boundary conditions,from that of a central liquid column, wi
th outer drops and ligaments, to, more typically, that of a chaotic 'w
ire wool' structure of ligaments and drops. Time variations of the bre
ak-up length are found during spray pulses and concentrations of poorl
y atomized liquid are convected downstream in the form of coherent str
uctures. The existence of this zone has repercussions with respect to
spray-gas flow interaction, fuel vaporization and wall wetting in inte
rnal combustion engines.