n-dodecane, 21% O2, 900 K, 22.8 kg/m3

See Skeen et al. 2016 , Manin et al. 2013, and the ECN soot diagnostics page for the experimental methodology.

High-speed line-of-sight extinction imaging provides a time-resolved measure of the optical thickness (KL) throughout at large region of the spray flame as shown in the movie below.

Download KL movie

High-speed KL images are processed to determine the onset time of soot. The total mass within the entire spray flame at each time step is computed. The time at which the total mass of soot within the flame exceeds 0.5 µg defines the onset based on the total mass. The total soot mass as a function of time is shown below.

Total soot mass (µg) as a function of time (ms) (right-click and select “save link as…”)

 

High-speed KL images are also processed to determine the onset location and timing of soot based on the soot mass observed at each axial position. A threshold of 10 ng resulted in consistency between this method and the total mass technique shown above. An example of the spatially resolved soot mass as a function of time is shown in the movie below. The derived onset times and location are tabulated below

Download soot mass movie (right-click and select “save link as…”)
Soot Onset Data
TambientρambientO2,ambientFuelInj. DurationNozzletonset, totaltonset, axialOnset location
[K]kg/m3%[ms][ms][ms][mm]
90022.821DN>43700.360.3923.1

 

Optical Thickness, KL

 

The ensemble-averaged KL maps at 1.5 ms, 2.0 ms, 2.5 ms, and 4.5 ms ASOI are shown below. These images, in conjunction with the total soot mass at their respective timings from above, can be used as a target for modeling efforts of soot in the Spray A condition (and its parametric variants).

The time- and ensemble-averaged KL map during the quasi-steady period of a 6-ms injection is also provided below. The time-averaging was performed between 2.5 ms and 6 ms ASOI. The visible region of interest (ROI) in the experiment extends from 15.2 mm to 67.2 mm, thus model comparisons should be made only within this ROI.

time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
1.5XYKL 1.5 ms PNG4.8907e+04KL 1.5 ms CSV

time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
2.0XYKL 2.0 ms PNG3.9961e+04KL 2.0 ms CSV

time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
2.5XYKL 2.5 ms PNG6.0125e+04KL 2.5 ms CSV

time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
4.5XYKL 4.5 ms PNG5.1200e+04KL 4.5 ms CSV


time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
quasi-steadyXYKL quasi-steady ms PNG7.6205e+04KL quasi-steady CSV

 

Soot Mass Data (DN, 900 K, 22.8 kg/m3, 21% O2, Nozzle: 370, Inj. duration >4 ms)
time ASOImasssoot

[ms][μg]1.511.342.012.642.510.694.510.42quasi-steady10.39

 

Soot Volume Fraction fv

Time-averaging over the quasi-steady period for each injection and subsequently ensemble-averaging multiple injection events yields an axisymmetric KL map that can be tomographically inverted to yield soot volume fraction, fv. For the fv map below, the incident LED light was centered at 406 nm and the non-dimensional extinction coefficient was determined to be 7.76 from Rayleigh-Debye-Gans theory for fractal aggregates. For more information see Manin et al. SAE-PFL-2013

time ASOI [ms]axial values (X) [mm]radial values (Y) [mm]16-bit PNGScale for PNG+.csv
quasi-steadyXYfv quasi-steady ms PNG7.2018e+03fv quasi-steady CSV

 

Soot Particle Sizing

Particles were collected on a transmission electron microscope (TEM) grid 36, 45, and 60 mm from the injector orifice at IFPEN. The TEM grids were shipped to Meiji University for TEM analysis. Measured particle diameters at these three positions under the Spray A O2 varient condition (21%) are shown in the figure below. Emre Cenker (IFPEN), Gilles Bruneaux (IFPEN), Katsufumi Kondo (Meiji University), Tetsuya Aizawa (Meiji University), and Christof Schulz (University of Duisberg-Essen) are acknowledged for the data shown below.

 

Last updated 12 March 2014