Orange Exhaust

[willedoo]

I've been curious for a while as to why the Tupolev Tu-160 bomber puts out orange exhaust and have finally found out that it's added nitrogen. Googling the subject doesn't shed much light on it and mainly comes up with academic papers waffling on at great length about American jet fuels. Question is, does it boost power or just make the engine burn cleaner, or both?

 

 

 

[pmccarthy1]

You get the same orange fumes from nitrous explosives. Nitrous oxides in air react to form nitric acid, very bad to breathe in. So I think this would be banned outside Russia.

 

 

[facthunter]

It could be a result of very high temp burning in air of any fuel. Nitrous oxides form  that way .   There used to be a layer of it hanging over Melbourne and when you descend through it the acrid smell goes through the pressurisation system into the cabin..Nev

 

 

[old man emu]

You can see the same thing over Sydney, but the Tree Huggers have solved the problem this summer by ensuring that the air in the Sydney Basin is filled with eucalyptus smoke.

 

 

[willedoo]

It would be interesting to know a bit more about it. They add the nitrogen when fueling up on the ground, but I'd assume it's separate storage and injected somehow. The orange seems to be only present on takeoff and I was wondering if the nitrogen is injected only during afterburner takeoffs.

 

Both bombers, the Tu-160 and the Tu-22 both burn blue with reheat, more so the Tu-22 and I was told that is ionization of the gas molecules in the flame due to the more complete combustion. But the nitrogen orange seems to be particular to the Tu-160 and not the Tu-22, which makes me think it's not the cause of the blue combustion. So maybe it's a power boost more than an additive for clean burning. Would it make the fuel burn hotter.

 

 

[Yenn]

I recently saw an article in Nature, that stated Nitrous oxides were over 200  times worse than Carbon dioxide for the environment.

 

Nobody else seems interested.

 

 

[facthunter]

Apparently Nitrous oxides are commonly used  to provide extra oxygen to burn more fuel for extra power.  That probably makes the nice blue flames on afterburn. No big deal except it's probably a bad polluter.. Nev

 

 

[pmccarthy1]

NOx injection is available for road registered sports cars if you want. I know someone who had it in a Mazda MX3.

 

 

[willedoo]

Apparently Nitrous oxides are commonly used  to provide extra oxygen to burn more fuel for extra power.  That probably makes the nice blue flames on afterburn. No big deal except it's probably a bad polluter.. Nev

 

That makes sense, Nev. Extra oxygen, more complete combustion, = nice blue flame. As opposed to no nitrogen, less efficient burning = normal red/orange reheat flame from unburnt gases exhausting.

 

 

[Yenn]

Surely the aim is not to get excess oxygen, but to enable more fuel to be burnt, producing more power.

 

 

[facthunter]

You get both Yenn. The engine is an air pump and can only process a certain amount of mass  airflow. By using"nitrous" and adding more fuel to match the extra Oxygen available you get more HEAT = more power. Rich mixtures Produce a Yellow-red torching exhaust due to unburned Carbon .The Hydrogen is burned preferentially as it's more chemically active. and the carbon particles incandesce  or sometimes form visible soot., like the early B 707's did..Nev