NITROUS OXIDE ( nos / n2o ) advice forum

Trev,
I believe Loopy was asking about a fresh bottle as a fresh bottle is not stabilized or constant to get accurate data. As you know the pressure can keep rising from the heat if pumped in.

I see there is a lot of catch-up for me in this thread and I'll try and jump back in when I get more time to think.

That's true Denny but we're talking about what was extracted from the bottle and how it performed once out of the bottle, not anything to do with the bottle itself or the contents before during or after the sample was removed, which is why I asked the question.

Regards

Hi All

Wow ..great thread....at least its making me think lol

As someone who knows little about Nitrous...when you are talking about various laws of physics.....

Surely they would work in two ways....

ONE law for Nitrous in bottle (mostly liquid)

ONE law for released Nitrous....(in pipes/solenoids)

ONE law for combustible Nitrous in engine (mostly gas)

Oops that 3 laws..lol...but I hope you see what I mean...

If you do....then try and combine all 3 laws together.....as a sequence...surely it gets too complicated to get a result ??

All the best Brett

My thoughts exactly Brett. We are dealing with different phases and multiple laws apply and you are right that there is plenty of thinking to address it all.

Hi Denny

Im not sure if thinking will help lol..

Possibly the answer lies in experience....you and Trev...KNOW what works...even if you dont know the reason WHY....

But thats good enough for me

All the best Brett

Brett,
We are good at applying logic and common sense but I feel there is that void of physics not being fully undertsood. If we can learn more about physics that can be applied then look out as nitrous can take one major leap.

Being an ex crew chief you can appreciate always fine tuning and looking for more efficiency and there is still some left on the table with nitrous.

Bret,

VERY TRUE!!!

In the 25 years plus of being involved with nitrous I've never considered even the existance of ANY rules.
When I left school at 16 years of age, I hadn't even learned about the basics of the 3 states of matter (gas, liquid, solids), never mind any of the laws that Loopy and other well educated guys know as well as the back of their hands.
Everything I know is as a consequence of self education and I think it's being free of all the laws that has let my brain be free of the confines such laws can create, especially if they aren't understood correctly or are applied incorrectly as is so often the case.

Regards

Hi Denny and Trev

I think I agree with Trev in this...when I was starting in Top Fuel....I "listened"...a LOT...FROM THE OLD HANDS...

I didnt ask WHY what they said worked...IT JUST DID...

Years later...when I was cheif....young fuel mechanics...did start asking why....my stock answer was...."Because I say so"

All the best Brett

This is where I started;

It's only SINCE that i've tried to understand WHY..........
And it hasn't been, isn't and more than likely won't be easy !
Brett > Dead right, we've got so many "laws" colliding working out what's really going on 'aint easy, but like Denny says

And he's right.
Trev, through whatever mystical means keeps on making nitrous faster (by using less) and as much respect as i have for his "UNcommon" sense it would be nice to have the theory behind it in black and white so to speak.....

I see you're not feeling yourself again just yet Trev, or i wouldn't be posting stuff you already know.......
Or are you making me do this for effect again ? I'm ill you know !
The circumstances surounding your sample matter a lot, being such a bad conductor it carries it's history with it for a good long while.
If the bottle you drew the sample from had recently been filled, it's entirely possible the contents had a physical temperature of maybe -20c but as the liquid contacted the bottle surfaces, that "boundary layer" was heated to "ambient" and that small total amount of liquid "boiled off" and created a bottle pressure equivilent to the ambient temperature.
OR simply the pressure differential of filling and the disturbance to the liquid created enough gas by reducing it's boiling point enough.
ERGO; The classic "fresh fill bottle, high pressure that drops like a stone during a run"
Liquid nitrous can be stored at ambient temperatures as long as the pressure is high enough, how much pressure would you need if it's temperature was low enough ?
Atmospheric maybe ?..................
Now prevent it transfering heat by putting it in a plastic cup, a liquid thats terrible at transfering heat let alone transfering heat from a layer of boiling off gas and I don't see 30 minutes as unreasonable.
Now did you think of dropping a temp probe in there while you stared at it ?
As far as temperature / bottle pressure goes we only need to apply enough heat to cause enough liquid to boil off and we have our pressure.
If the bottle was kept still and we drew from the bottom then 90% of the contents could be at critical temp, the bottle showing critical pressure yet we'd still have liquid at the outlet.
It's weird old stuff but at this point it's still behaving as any hot / cold, dense / less dense, gas / liquid would, cold and dense stuff at the bottom.
Once the entire contents were at critical temp we would start dispensing actual supercritical nitrous.
They were having this problem at one of the hybrid rocket competitions last year, they fill very slowly to get a maximum fill but without insulation and with high ambient temperature donor bottles they were going supercritical while on the launch pad.
Que lots of fizz with no pop !
Bear in mind these aren't sealed bottles as such and are very thin walled.

After quickly reading this through i've realise two things;
I still don't feel very well and don't make much sense.
None of this makes us go faster

And quit calling me educated ! I'm just a dumb grease monkey who's never done and isn't likely to do 8 seconds, but at least it's not a load of endless technobable that goes around and around without actually saying anything..............

You could have fooled me, especially this time round as you lost me after the first line and I need to try and work this through with Ant.

My first guess is that you may be combining 2 different aspects of my posts in one, which would explain why I'm struggling to get a handle on what you're saying.

By the way I'd also like to have someone explain what I 'beleive' I know (due to our UNcommon sense) by stating a suitable law, because it seems most people who 'know' (but I believe don't fully understand) the laws, keep telling me I'm wrong!
One thing that makes confident such people are the ones wo are wrong, is the fact that these people ('experts') make such statements purely on what they 'think' they understand about the laws and not due to any practical experience of the superior results my systems produce and to me those educated guys making such statements aren't very smart and certainly don't have my UNcommon sense.

Regards

It's probably my fault, I'm struggling to think straight, let alone type straight.

The basics of what i'm saying is that the bottle contents BEFORE the sample was extracted matter a LOT.
Due to the slow heat transfer through liquid n2o your sample could possibly have been near frozen solid when dispensed yet the bottle could have been hot to the touch.

When they write tech specs they use constants as baselines which means (for example) keeping a bottle and contents at a set temperature for (example) 48 hours to ensure the entire contents is at the temp they say it is.

I believe the problem with such "experts" is that it's entirely possible to be educated beyond ones intelligence.
I was once told true scientists are never happy, they come up with a theory and spend the rest of their lives trying to prove it wrong. If they can't then they've failed.
Compare that to nitrous "experts" who base theories on flawed observations and spend their lives trying to prove it right, bending any such laws to fit................

(NOTE; I'm not in any way comparing myself with a scientist, I simply like their way of thinking.)

I just can't see how a few degrees either way can make any difference.

What I don't understand about that episode is;
The boiling point is claimed to be MINUS 128 degrees, so why didn't the whole lot instantly change to gas at room temp???
Now if it had taken a few seconds or even a minute or two I might have been able to live with that but 1/2 an hour or more just seems insane.

Your answer seems to be that it's all just due to it being a bad conductor of heat and if that is the correct and full explanation for it, then I'd say it's bloody terrible rather than just bad.

Also if the liquid we expel from a bottle at 900 ish psi almost instantly changes to gas at room temp why doesn't the liquid do the same when it's not under pressure??

Now I've made some good guesses at asnwers to this but if you can give me some solid stuff I'd be happier.

By the way sorry to be taxing you when you're ill but I just had Brad doing the same to me, so it's only fair.

Regards

Hi Loopy

This quote of yours...." I believe the problem with such "experts" is that it's entirely possible to be educated beyond ones intelligence. "

I SOOOOOOOOOO love that....

I have met hundreds of people like that....example.....I met an "Electrical engineer" once who built huge electrical systems for Arab oil fields.....and he didnt know how a standard car alternator worked lol

I am going to remeber that quote....lol...absolutely brilliant ty

All the best Brett

At roughly atmospheric pressure the true boiling point of liquid N2o is
-88.5 C
Not such a hard figure to reach or get close enough to, not when you consider you "trapped" it in a cup.
For a liquid to vapourise it requires heat, being such a bad conductor the nearest form of heat is itself which then cools the liquid even further.
The only other heat available to it is from the cup and from the atmosphere.
Like the difference between a small deep puddle and a large shallow puddle the small one has a smaller area through which to absorb heat.
The small deep puddle (cup of nitrous liquid) takes ages to "evaporate" whereas the big shallow puddle (nitrous sprayed) "evaporates" quicker.
The other thing to bear in mind is that the surface of this puddle is actually boiling off, not transfering heat back into itself.

You've effectively refrigerated it.
Like storing liquid oxygen at low pressure, you simply need a low enough temperature !

Thinking about it, I believe this may even be possible with an ambient bottle and practice.
If i'm right that is.............

I am following Loopy.

For instance my wife likes those drinking mugs where there is liquid trapped between the layers of plastic. You put these in the freezer and your beverage of choice stays nice and cold when poured into the mug.

Now more times than not if you pour a cold liquid into the mug the liquid will convert a good part of itself to a slush and remain that way for quite some time even though the top is exposed to the ambient temps.

As Loopy said the liquid nitrous is self refrigerating itself and retaining cold enough temps to stay in a liquid state for a given time.

Now why this may not be the case in an actual nitrous line is on the tip of my brain but I want to think this through a little more before I post what could be rubbish.

Trev,
Could you guys repeat the liquid test and stick a thermometer into the liquid? This will confirm our refrigeration idea.

Thats exactly what i'm thinking.
Trev, you seem to think nitrous can draw heat from the air easier than drawing heat from itself (the heat required to vapourise)
I don't believe that's so.
Being a bad conductor means the first place it will draw heat from is itself.
Drawing heat from itself is self refrigeration.

Don't get me wrong, it's suprised me that it's possible but since it is then it's entirely plausable and one of the reasons i've never doubted the "increase in liquid density within the pipes" theory.
It really doesn't transfer heat very well.

Not for nothing did I use the phrase "trapped it in a cup"
In "trying" to escape it made it's own jail cell.
A heat differential means nothing if you can't access it.
In your example you say the cold bottle acted as a "cold sink"
I say the liquid itself was the "cold sink"
I say the bottle was actually a "heat sink", it has more heat differential to give up than a plastic cup despite being cold.
Is anyone else considering the recovery time penalty of using a composite bottle right about here ?

The lack of surface boiling doesn't suprise me either, the very boiling is refrigerating the nearest thing in terms of available heat, the top layer of liquid. NOT atmosphere.
I theorise that were we able to measure it, the upper layers would actually be colder than the bottom layers

Why we don't end up with liquid nitrous in the pipework seems quite simple, it doesn't have the volume / surface area ratio within the pipe to self refrigerate, the differential heat of the pipework is easier to draw from or rather has a larger effect than the evaporation refrigeration.
I'd fully expect there to be a certain surface area / volume ratio where this effect is obvious and other ratios where it's impossible.
Anyone fancy a vat of liquid nitrous ?

It's a shame i'm not classically educated, if i'm right i'd already have the mechanism to get what i think accross built in through sitting in classes.
As it is, I know what i mean !

I promised myself I wouldn't post in this thread, but just to help it along a bit I think that you are asking why nitrous boils at -88.5 but is a liquid when in a bottle at room temperature. (Hopefully I'm not misreading your statement)

Basically it's because the higher the pressure, the higher the boiling point. If you think of molecules as little bouncy balls, the more energy they have (i.e. the higher the temperature) the more the bouncy balls will want to spread apart (i.e. a gas). But, if you cram a whole ton of those bouncy balls into a limited space (i.e. increase the pressure), you have more of a tendancy to be a liquid because they can't bounce far away from each other.

Also, the difference betweeen a gas and a liquid is that a gas will expand to evenly distribute itself within its container, but a liquid will stay together as a single mass (or glob or puddle or whatever you want to call it). Both are "fluids" (i.e. they "flow).

Even if that doesn't address your statement exactly, perhaps it will help some other readers.

-Bob C.

Hi Bob,

That's how this thread started but we've moved on to an experience I had with LIQUID nitrous in a plastic cup at ROOM TEMP. & PRESSURE, which I found AMAZING and Loopy is trying to explain why it's possible.

Thanks anyway, because as you say that may help others.

Regards

OK I think I'm with you on all that although it's still a strange concept to grasp.

On the final point about the liquid in the pipe, I'm with you now but you gave me a good explanation (which I don't want to disclose here) over a year ago for why you thought that was and I fully agreed with it.

I've been using the principle on high end installs ever since.

Regards

All this talk about boiling points and stuff,
It's got me thinking about nitrogen boosting in a lot more detail...............
Related it to composite bottles too.

(I've never REALLY thought about it with regard to its use by people such as Johnny)

Hmmmmmm.....................