Jet Fuel

M. J. Powell wrote:
In message , Tarver Engineering
writes


"M. J. Powell" wrote in message
...

In message , John
Mullen writes
Clark wrote:
"M. J. Powell" wrote in

news:Uj2uRaHhqv2$EwF0

@pickmere.demon.co.uk:

In message , Clark
writes

Do your homework Mike and you will be able to answer your question.

I asked because I don't want to do more homework!

So, how's that working out for ya?


Assume jet fuel is pure decane, to simplify the calculation.

C10H22 + 15.5O2 - 11H20 + 10CO2

1 mole C10H22 = 142g
1 mole H2O = 18g
1 mole CO2 = 44g

So for every tonne (1000kg) of decane burned, assuming 100% combustion,
you will have

1000000/142 * 11 * 18g = 1394360g = 1394kg water
1000000/142 * 10 * 44 = 3098590g = 3098kg carbon dioxide

Which comes to about 4492kg of products. Where does the extra weight
come from?

Obviously from the oxygen used to burn the fuel, which comes to

1000000/142 * 15.5 * 32g = 3492957g = 3492kg

The assumptions made won't have much effect on the calculation, and
neither will rounding error. The biggest error probably comes from the
100% combustion; from the smell they make, most jets give out quite a
bit of unburnt fuel. Right ball park though.

HTH

It does indeed. Thank you very much.


Just remember not to confuse a metric ton with 2000 lbs.


I'm used to 2240 lbs/ton.

Mike

Well you can just scale it up, it's a ratio. 1 ton of fuel + 3.5 tons
oxygen gives 1.4 tons water and 3.1 tons carbon dioxide, whichever
version of the ton/tonne you use, and there are at least three that I
know of!

John

In message , John
Mullen writes


Just remember not to confuse a metric ton with 2000 lbs.
I'm used to 2240 lbs/ton.
Mike

Well you can just scale it up, it's a ratio. 1 ton of fuel + 3.5 tons
oxygen gives 1.4 tons water and 3.1 tons carbon dioxide, whichever
version of the ton/tonne you use, and there are at least three that I
know of!

Yes, thank you. It was just the round figures that I wanted to bolster
up my general theory about the weather.

Mike
--
M.J.Powell

In article , John
Mullen wrote:

The assumptions made won't have much effect on the calculation, and
neither will rounding error. The biggest error probably comes from the
100% combustion; from the smell they make, most jets give out quite a
bit of unburnt fuel. Right ball park though.

You only smell them when they're on the ground (for the most part)
and operating at partial throttle and low Tit.
When they're operating at higher throttle settings and higher
temps the combustion is more complete.
The higher combustion temp also forms NOx's.

--
Harry Andreas
Engineering raconteur