Effect of Gasoline Fuel Additives on Combustion and Engine Performance

K
inem
a
tic 
Vis
co
sit
y
, 
m
m
²/
s
Temperature, Deg C
Esteban et.al. (2012)
Malvern Measuring Points
16 °C 
20 °C 
25 °C

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5.2 Droplet Sizing with Alternative Fuels 
127 
improved evaporation. Mixtures of heptane and toluene were carried out in pure and 
in a 50 % mixture forms. The main aim of the investigations was to determine SMD 
for pure and mixture forms in order to understand if physical properties of the fuels 
can be used to explain the effects combustion, as found by Hellier et al. [242].
Furthermore, it was thought such fundamental study would enable better explaining 
results obtained from droplet sizing with additives. 
5.2.2.1
 
Hexene and Dodecane Binary Mixtures
The pressure dependence at minimum transmission of the pure forms and 
blends can be seen in Figure 5.12. Evidently, hexene produces smaller droplets than 
dodecane under the same experimental conditions. Binary blends at higher pressures 
separate nearly evenly between pure forms but at lower pressures, especially at 50 – 
70 bar, seem to tend towards the SMD size of dodecane. It is possible that this is 
caused by the hexene portion of the fuel blend evaporating faster than the dodecane 
portion, thus, the tendency towards the dodecane SMD. However, this effect should 
be seen throughout the pressure range, which is not the case for the current set of 
experiments. As such, the results can more likely be explained by limitations in 
experimental repeatability rather than fuel blend effects. 
 
Figure 5.12: Pressure dependence of hexene and dodecane in pure and blended forms at