Fuel/oxidizer preheating to a high temperature

[Tera]

imagine you burn something, like H2 in O2. let's say you have a nice flame with a temperature T. for the sake of this discussion let's assume that T is 1000.

what happens if you preheat both H2 and O2 to 1000 first? is the resulting flame temperature higher? does the flame look the same? what happens if you preheat both H2 and O2 to 2x1000 or 5x1000 or 10x1000 ?

 

[DrStupid]

what happens if you preheat both H2 and O2 to 1000 first? is the resulting flame temperature higher?

Yes.

what happens if you preheat both H2 and O2 to 2x1000 or 5x1000 or 10x1000 ?

The reaction will become less efficient. At around 3000 K only half of H2 and O2 will burn to water. At 10000 K nothig happens anymore.

 

[hilbert2]

The explosivity limits of a gaseous fuel-oxygen mixture are also wider if the mixture is pre-heated, and an electric spark of smaller energy is sufficient for ignition. If a $H_2$/$O_2$ mixture is heated close enough to the autoignition temperature, something like a single stray particle of ionizing radiation may be enough to trigger the explosion. That's the reason why the most sensitive explosive compounds may sometimes go off for no obvious reason.