Aj. Yule et Dg. Salters, THE BREAKUP ZONE OF A DIESEL SPRAY .1. LENGTH OF ZONE AND VOLUME OF UNATOMIZED LIQUID, Atomization and sprays, 5(2), 1995, pp. 157-174
A new conductivity probe technique is applied to high-speed, pulsed di
esel sprays to measure the dimensions and time dependency of the break
up zone. Variations are made of liquid properties, gas density, and or
ifice size. A flat-plate probe is used to detect the contiguous liquid
in the breakup zone. Breakup length is of the order 100 nozzle diamet
ers at engine conditions of gas density, and a increases with increase
of liquid viscosity and reduction of gas density. Typically, of the o
rder of 1% of injected liquid is measured to be incompletely atomized
at 100 diameters downstream. Some agreement with published correlation
s for breakup length is found; however, a is shown that liquid viscosi
ty should be included in correlations and analyses of breakup, and not
simply the ratio of liquid and gas density as in some previous work.
A revised correlation gives reasonable agreement with the new data. Th
e breakup length is found to vary throughout the spray pulse, reflecti
ng, in a complex manner, the time-varying flow rate produced by a conv
entional injector and pump. Periodicity of the breakup zone structure
is noted at frequencies of the order 10 kHz, and this appears to be in
accordance with published results using photography and laser anemome
try.