On the Formation of Nitrogen Oxides During the Combustion of ...

3.1 Droplet Combustion Facility
for 5, 9, 13, and 17 droplets were manufactured and used in the experiments.
The deviation of the orifice area within the glass tube sets composed was below
±5µm 2 . For the TEXUS-46 sounding rocket campaign, this resulted in a
maximum error of the generated droplet diameter D 0 from its nominal value
D 0,nom = 1.5 mm of less than 5%. The diameter reproducibility within the experiment
campaign was high, with a deviation below 1%.
3.1.2 Droplet Suspension Technique
In order to generate a droplet array, the droplet array generation device interoperates
with the droplet array holder (Fig. 3.6). The latter features the
droplet suspension technique, as reported in Avedisian and Callahan [28] and
Mikami et al. [282, 283]. Silicon carbide (SiC) fibers are aligned as X-shaped
fiber pairs, corresponding to the fine glass tubes of the droplet array generation
device (cf. Fig. 3.5). A single suspension fiber has a diameter of 14µm
(manufacturer: Nippon Carbon; type: Hi-Nicalon). It has a low oxygen content,
is heat resistant up to 1700 ◦ C in an inert gas atmosphere, and is primarily
designed for application in the hot parts of gas turbines. The SiC fiber setup
imposes smaller disturbing effects on shape and heat transfer of a tethered
droplet than the most commonly used quartz fibers of 100 to 150µm diame-
A
B
Figure 3.6: Droplet Array Holder. The assembly is shown for a setup of five droplets, as used
on the TEXUS-46 campaign [196, 208]. A: tethered fuel droplet, B: ignition wire.
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