AIAA-2015-3867 Effect of Water and Humidity on Hypergolic Propellant Ignition Delay
Figure 5. Video frames from a representative test (Case #1). Recorded at 20 000 fps, 48 s exposure, 256 x 400 pixels The IDT on the photodiode is marked when the signal rises 100% higher than the noise level. Similarly the onset of the streak camera signals occurs when the intensity is 100% higher than noise. Successful ignition captured by the streak camera for both TEAB and MMH tests show strong signals around 306 nm, 310 nm, and 336 nm. The 306 nm and 310 nm signals have nearly identical profiles and are believed to both be the OH radical. The signal at 336 nm is believed to be the NH radical As illustrated in Figure 6, the NH signal is typically much weaker than the OH signal.
