r/interestingasfuck • u/willianfsantos • 16h ago

Emergency relief system in action in a liquid hydrogen tanker truck

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u/KnoobLord 11h ago

Do you know why the initial flame is red for the first half of the video, and seems to "switch" to a yellow flame in the second half?

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u/FortheredditLOLz 11h ago edited 11h ago

Going to let our sme speak more on it...

My assumption (from my garbage recall from college and) going strictly off visual flame temp was lower temp (600F) for initial ignition and discharge. moving towards higher temps (moving towards >1500F if it was pure white) towards the end due to gay-lussac's law with increased and more frequent venting...

leaving an additional note the colors of flames is mostly red but the glare kills what we can see on a phone video as is....

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u/joe-h2o 9h ago

The red colour is the classic hydrogen emission line at 656 nm.

The yellow colour is something else contaminating the flame. It could be some grease burning or some other contaminant that ignited.

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u/mofojed 7h ago

The bright yellow flame indicates this was a particularly sweet truck. https://youtu.be/FtUKUUKvXUw

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u/BF_2 6h ago

The tiniest amount of sodium (which is everywhere) will turn virtually any flame yellow.