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

 

 

[Phuh gough]

I'm pretty sure the engines in the aircraft are over powered for lift off. They use them at half power until clear of the ground and then when the danger of shockwaves from the ground they power up. 

[turboplanner]

NOx has been reduced in motor vehicles since the 1976 model year in Australia via the Australian Design Rule system and had been reducing to 1992 when major reductions started because it is one of the causes of Lung Cancers.

Since 1992 in Australia we have reduced NOx in new vehicles by 99.4% on the 1992 figures.

We pay a lot of money for this on new vehicles, and it would be interesting to see if there were any statistics on a parallel reduction in lung cancers.

 

 

[Phuh gough]

1 hour ago, Phuh gough said:

I'm pretty sure the engines in the aircraft are over powered for lift off. They use them at half power until clear of the ground and then when the danger of shockwaves from the ground they power up. 

This is why there is extra orange smoke during takeoff. It is less efficient to run them this way causing extra emissions. 

[facthunter]

Take off power is MAX on pistons and is where the mixture is enrichened to reduce detonation. It's often limited to 5 minutes use.  Nev

[Phuh gough]

On a t-160. Ok?

[facthunter]

After 4 YEARS I thought a bit of drift might be OK.   Nev

[Phuh gough]

15 hours ago, facthunter said:

Nev

Drift away. I thought this was a place for actual answers. 

[danny_galaga]

On 01/05/2024 at 4:21 PM, turboplanner said:

NOx has been reduced in motor vehicles since the 1976 model year in Australia via the Australian Design Rule system and had been reducing to 1992 when major reductions started because it is one of the causes of Lung Cancers.

Since 1992 in Australia we have reduced NOx in new vehicles by 99.4% on the 1992 figures.

We pay a lot of money for this on new vehicles, and it would be interesting to see if there were any statistics on a parallel reduction in lung cancers.

 

 

 

In any case, it's not good to breath so having it reduced is a good thing, no?

[facthunter]

Makes plants grow. Generated naturally by lightning.  Called laughing gas, used as an anaesthetic.  Nev

[Freizeitpilot]

and nangs now litter the back alleys.

[turboplanner]

1 hour ago, danny_galaga said:

 

In any case, it's not good to breath so having it reduced is a good thing, no?

Yes.

The automotive and transport industries are the leaders in this. Emissions are regulated from the time you turn the key on until you turn it off.

Static Industries are way back in the dark ages with politically tainted legislation which allows them to emit but then average what they emit over 24 hours and that's on top of higher emissions anyway.

 

[facthunter]

It's done by exhaust gas recirculation which reduces combustion temps but also reduces efficiency so more CO2./ km  The worst pollution is diesel particulates for human health and SO2 where the fuel is really crook. .  Nev 

[turboplanner]

47 minutes ago, facthunter said:

It's done by exhaust gas recirculation which reduces combustion temps but also reduces efficiency so more CO2./ km  The worst pollution is diesel particulates for human health and SO2 where the fuel is really crook. .  Nev 

In motor vehicles, we started taking visible particulates (black smoke) out of diesel exhausts in 1976. By 1992 we were down to  about Ringelmann 3 (slight haze).

Since 1992 we have reduced diesel particulates by 98.4% of the 1992 PM levels.

[spacesailor]

Even the manufacturer of certain diesel motors,  have said to put a " blanking kit " in your motor , to make it last longer , plus be more economical & extend the oil changes .

Going up a certain steep hill in a similar truck , one with that kit , the other without ,

You certainly can feel the difference,  the EGR makes to your power .

And a much lower ' litres per hundred kilometres ' .

spacesailor