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

3.1 Droplet Combustion Facility
• High surface quality – by applying surface coating
• High temperature resistance – by using special sealing
• High vacuum level and low leakage rate
As illustrated in Figure 3.2, the EGS system is installed on the fifth experiment
platform, in close proximity to the combustion chamber. It is shown in greater
detail in Figure 3.9. The installation directly above the combustion chamber
is chosen to keep the dead volume of the piping low, which results in low contamination
of the samples and an optimized performance of the EGS system.
The design meets the strict relation of V piping /V sample ≤ 1%, and the piping itself
has a surface to volume ratio of 1.85 with an inner diameter of D i = 2.16mm.
Since four combustion runs were scheduled on the TEXUS-46 sounding rocket
campaign, the layout is based on four sample cylinders. Each of them has a
volume of 200 ml, which is optimized towards the minimum volume required
for gas analysis. All metal surfaces of the EGS system being directly exposed to
the combustion products are coated with amorphous silicon 1 to prevent negative
surface effects on the gas composition and a distorting gas adsorption.
B
C
A
D
Figure 3.9: Exhaust Gas Sampling Platform. Left: top view, right: bottom view [196, 197, 293,
294, 296]. A: sample cylinders, B: solenoid vacuum valve for connection to combustion
chamber, C: solenoid vacuum valve for connection to evacuation line, D:
vacuum gauge.
1 Sulfinert ® coating was used instead of the Silcosteel ® coating mentioned above. Both are very similar from the
chemical point of view but have different product names.
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