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Plas Steel and Adamantium?

Started by Adlan, September 02, 2009, 10:44:00 AM

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psycho

check out X-Men, as in Wolverine, for adamantium
hes had the stuff surgically grafted to his skeleton

kerby

Tullio

Quotecheck out X-Men, as in Wolverine, for adamantium
hes had the stuff surgically grafted to his skeleton

Yeees, but these are two different sets of intellecutal property. The properties of adamantium in X-Men don't really apply here

Tullio

psycho

just spit balling lol, im sitting here watching Xmen with my old man so thats where my answer comes from
kerby

N01H3r3

Quote from: MarcoSkoll on September 06, 2009, 08:05:01 PMEither way, it's still a good piece of television.
And, to be fair, the whole show is an exercise in not caring about the technical details...
Contributing Writer for many Warhammer 40,000 Roleplay books, including Black Crusade

Professional Games Designer.

InquisitorHeidfeld

Fuel burning in tanks...

1, A mix of fuel and oxidising agent does not immediately burst into flame.
In its simplest form let's consider an Oxy-Acetylene torch. The mixture of Oxygen and Acetylene coming out of the nozzle is stable. It is an explosive mixture but without external influence it will do very little.
The mix of fuel and Oxidising agent can be "safe" if it is tailored to have a high enough ignition temperature to limit risk. If the fuel mix has an ignition temperature around its 900° Combustion temperature and a high enough specific heat capacity that small sparks, las blasts...etc are smothered by the fuel before they can ignite it then the risks of tank fires are minimised.

2, Flames cannot pass through small appetures, the plasma boundary simply cannot sustain itself below a certain size - going back to the Oxy-Acetylene torch the fuel is mixed with oxygen well down the torch, but no combustion occurs until the flame boundary at the end of the torch.
If the flame could cross the plasma boundary then Oxy-Acetylene would be impossible to use - the hose and the metal of the oxygen cylinder would be more than sufficient fuel.


Radiant Heat

You (Marko) seem to have a very low opinion of the capacity of radiant heat...
Hold your hand close to the side of your cup of tea/coffee - the heat you're detecting is predominantly radiant. There is some conducted through the air between your hand and the mug but air has a very low specific heat capacity and therefore you need a large amount of it to contain any significant quantity of heat (not temperature but heat). Water (of which I hope your tea/coffee contains a considerable proportion) however has a very large specific heat capacity.
Most of the heat loss from your mug of tea comes in the form of evaporation, energy usage, a state change from liguid to vapour and therefore a conversion of heat energy to kinetic energy plus a mass loss from the system. A significant portion comes from convection, another heat to kinetic energy transfer... but a significant portion, almost a quarter IIRC of the heat loss is through radiation.
Radiation is considered a short ranged method of energy transfer - predominantly because in atmosphere radiated heat quickly transfers to matter and becomes convection or conduction. In hard vacuum however it is more efficient simply because there is so little in the way.

MarcoSkoll

Quote from: InquisitorHeidfeld on September 07, 2009, 01:29:34 PMThe mixture of Oxygen and Acetylene coming out of the nozzle is stable. It is an explosive mixture but without external influence it will do very little.
I'd hardly call something with ignition energies in the microjoules stable. 17 microjoules in air. About 100 times less in an oxy/acetylene mix, with an exceptionally wide explosive limits of 2.5% to 82% in air.

Very bad example.

QuoteThe mix of fuel and Oxidising agent can be "safe" if it is tailored to have a high enough ignition temperature to limit risk.
Which is pretty unlikely. Oxidised mixes, particularly homogeneous ones, have very low ignition energies. Like I said above, acetylene needs 100 times less energy to ignite it in pure oxygen than in air.

QuoteIf the fuel mix has an ignition temperature around its 900° Combustion temperature and a high enough specific heat capacity that small sparks, las blasts...etc are smothered by the fuel before they can ignite it then the risks of tank fires are minimised.
Firstly, see above statement on the unlikelihood of such a mixture.

Secondly, you should pay more attention to ignition energies than ignition temperatures. The latter is of little relevance when discussing the likelihood of accidental ignition.

Quote2, Flames cannot pass through small apertures.
Only partially true. It can happen under some circumstances - and I know, having done it. The circumstances in a flamer are likely to be one of those, particularly with oxidisers present.
Truth is, we need to talk not just about aperture size, but the ratio involved when talking about flame arrestors.

But anyway, you're confusing "unlikely to explode" with the correct answer of "We have taken every possible precaution to avoid it combusting."

QuoteYou (Marko) seem to have a very low opinion of the capacity of radiant heat...
Firstly, there's a K in Skoll, but there's not one in Marco.

Secondly, I'm an engineering undergraduate. I don't think it would entirely inaccurate to say know a bit about heat transfer.

I don't have a low opinion of radiant heat - the best thermometer I own works solely on radiant heat. However, I do have an accurate one.

Take your cup of tea/coffee (it can't be mine, I don't drink either), and leave it, preferably covered to minimise heat loss from convection. Put it on a heat insulator to help reduce temperature loss to the surface it's on as well.
Five minutes later, it's still going to be pretty hot, so even accounting for the fact that water has a high specific heat capacity, it's not shifting too much energy at 100 degrees.

Now, consider the heat energy generated by a gun. An automatic AR-15 will generate easily 20 kW of heat when firing. Without any heat loss, That's enough to increase the barrel's temperature by 50 degrees per second of firing.

Calculating radiant heat from the barrel means that even if we assume there is no received radiant heat (which would be nonsense, particularly inside a space craft), under constant firing (also nonsense, but whatever), the barrel's equilibrium temperature would be 2000 Kelvin - more than hot enough to melt it.

However, a barrel doesn't need to be hot enough to melt it in order to be doing it damage. Hotter than 600 Kelvin would be starting to push it, and to maintain that as an equilibrium temperature, you only need to be firing for seven rounds (one half second) a minute.
Of course, it takes more than that to reach said temperatures, but let's say that in a combat situation, you're firing 50 rounds each minute (~1 second of firing in every 20). Your barrel would eventually reach equilibrium at 975 Kelvin, way more than enough to be doing it damage.

I'm also even doing the calculations with simplifications that assume the barrel is perfectly thermally conductive. In reality, it is not, and it's only the inside of the barrel that needs to get too hot, and it's the (cooler) outside of the barrel which is responsible for radiant heat loss.
So in reality, the amount of fire you could maintain without damaging a firearm in space is even lower than these figures.

Hence, I maintain my earlier point that radiant heat loss is not nearly enough to allow you to keep using a firearm as you normally would.
S.Sgt Silva Birgen: "Good evening, we're here from the Adeptus Defenestratus."
Captain L. Rollin: "Nonsense. Never heard of it."
Birgen: "Pick a window. I'll demonstrate".

GW's =I= articles

InquisitorHeidfeld

Quote from: MarcoSkoll on September 07, 2009, 07:03:30 PM
I'd hardly call something with ignition energies in the microjoules stable. 17 microjoules in air. About 100 times less in an oxy/acetylene mix, with an exceptionally wide explosive limits of 2.5% to 82% in air.
It's stable without outside influences - it does not self combust.

QuoteWhich is pretty unlikely. Oxidised mixes, particularly homogeneous ones, have very low ignition energies. Like I said above, acetylene needs 100 times less energy to ignite it in pure oxygen than in air.
But it's not impossible by any means.
Volatility is the important factor - adding an oxidising agent will increase the effective volatility but with the right tailored mix...

QuoteSecondly, you should pay more attention to ignition energies than ignition temperatures. The latter is of little relevance when discussing the likelihood of accidental ignition.

Ignition temperature is (relatively) constant, Ignition energy significantly less so.

Quote
Quote2, Flames cannot pass through small apertures.
Only partially true. It can happen under some circumstances - and I know, having done it. The circumstances in a flamer are likely to be one of those, particularly with oxidisers present.
Truth is, we need to talk not just about aperture size, but the ratio involved when talking about flame arrestors.
How the vortices form and interact and how conductive the material surrounding the vortex is is even more important... and reasonably predictable.

QuoteBut anyway, you're confusing "unlikely to explode" with the correct answer of "We have taken every possible precaution to avoid it combusting."
Touché.
My riposté:
I think you're confusing "unlikely to explode" (ie less than 50% chance) with "chance to explode compliant with design levels".

Quote
QuoteYou (Marko) seem to have a very low opinion of the capacity of radiant heat...
Firstly, there's a K in Skoll, but there's not one in Marco.
Apologies. My bad.

QuoteSecondly, I'm an engineering undergraduate. I don't think it would entirely inaccurate to say know a bit about heat transfer.
I've been a professional engineer for more than 15 years. I work within a sphere where managing heat loss is incredibly important.

Quote<Snip>
Hence, I maintain my earlier point that radiant heat loss is not nearly enough to allow you to keep using a firearm as you normally would.

Maintaining 600RPM from an open bolt weapon in a hard vacuum I would agree... But then maintaining 600RPM in an air cooled, open bolt weapon will allow barrel creep in atmosphere.
But Bolters are another matter.
The design is, to my mind, neither air nor fluid cooled. The sheer mass of the barrel suggests heat sink - and equipping Space Marines (the clue is in the name) with a weapon which operates at sub-optimal efficiency in a hard vacuum is simply bad design.

precinctomega

Gents,

You're both very, very clever and interesting.  Stop arguing and let the rest of us get on with gawping in awe.

R.

MarcoSkoll

Quote from: InquisitorHeidfeld on September 08, 2009, 01:43:34 PMIt's stable without outside influences - it does not self combust.
It may not self combust, but battlefields are however full of such external influences.
If we take a lasbolt to be very focused and energetic, we can almost certainly guarantee that the heat generated, at least locally, will be sufficient to exceed ignition temperature and ignite the fuel.

If an oxidiser is present, this will then result in combustion (and probably explosion) of the tank's contents. If not, then it will result in a rather impressive gout of flame from the tank. Neither is particularly desirable, but the latter is likely to be less of an issue. And again, the oxidised mixture is still almost certainly going to be more prone to ignition.

QuoteI've been a professional engineer for more than 15 years. I work within a sphere where managing heat loss is incredibly important.
While impressive credentials, they don't mean that my knowledge of the area is in error.

Either way, I have specifically sat down and done maths that told me unambigiously that you could not practically use an M-16 (first weapon for which figures were easily available) in a vacuum for any prolonged time if relying on solely radiant heat loss to cool it, and unless you want to show me other maths to prove otherwise, I stick by the point.

QuoteBut Bolters are another matter. The design is, to my mind, neither air nor fluid cooled.
The 3rd Edition 40K rulebook's picture of a storm bolter (p 60) shows air cooling vents are present on at least some models.
Anyway, simply having a hot weapon in air will result in heat loss to the surrounding air. A weapon may not make special provision to be air cooled, but they will derive at least some cooling from the air around.

QuoteThe sheer mass of the barrel suggests heat sink - and equipping Space Marines (the clue is in the name) with a weapon which operates at sub-optimal efficiency in a hard vacuum is simply bad design.
... and given the fact that the game designers are not gun designers, the design they use being bad (or incapable of what is claimed of it) sounds like a very likely situation.

No liquid cooling, a lack of atmosphere for air cooling and the low power dispersal of radiant heat loss means that unless they've found a way to dramatically reduce heat transferred to the barrel (either by lower heat conductivity or cooler propellants) or some new method of disposing of said heat, bolters could not realistically work in a vacuum as they are depicted.

So, while I accept that bolters can be and are used in vacuums to at least some degree of effectiveness within the fictional universe, I am saying that the same could not be replicated in reality.
S.Sgt Silva Birgen: "Good evening, we're here from the Adeptus Defenestratus."
Captain L. Rollin: "Nonsense. Never heard of it."
Birgen: "Pick a window. I'll demonstrate".

GW's =I= articles

Koval

QuoteSecondly, I'm an engineering undergraduate. I don't think it would entirely inaccurate to say know a bit about heat transfer.
QuoteI've been a professional engineer for more than 15 years. I work within a sphere where managing heat loss is incredibly important.
QuoteWhile impressive credentials, they don't mean that my knowledge of the area is in error.

I agree with what Robey said, folks, this is turning into a Cigaro scenario. At the very least, get some ground work down and then build up from there so that the uneducated masses (like me) know what the hell you're arguing about.

TheNephew

To be honest, I'm not sure the groundwork will make the heated debate any more relevant.
I expect Marco at least will disagree with me, but I don't think we need to know these things about the bolter or flamer.
Or, at the very least, not in a thread about plasteel and adamantium.

MarcoSkoll

Quote from: TheNephew on September 08, 2009, 06:47:39 PMI expect Marco at least will disagree with me, but I don't think we need to know these things about the bolter or flamer.
Not at all. Having done the maths, I'm convinced it couldn't work in real life, but this is a point that I'm happy to let be. Generally, if I actually had to do anything more than the most basic of mental maths to be entirely sure of something being wrong*, then it's close enough.

*The exception being when I know something is wrong, and I'm doing the maths to find out how ridiculously bad...
S.Sgt Silva Birgen: "Good evening, we're here from the Adeptus Defenestratus."
Captain L. Rollin: "Nonsense. Never heard of it."
Birgen: "Pick a window. I'll demonstrate".

GW's =I= articles

Koval

I'm a little concerned that there's mathematics to do for bolters when the specifics about dimensions, mass, the propellant in the shells etc. are so elusive...

MarcoSkoll

I reverse engineered a lot of information about bolters a couple of months ago. Enough to do the calculations in question, but for practical reasons, I did the maths with the data of the M16 instead. The information from it is still informative about using guns in a vacuum.
S.Sgt Silva Birgen: "Good evening, we're here from the Adeptus Defenestratus."
Captain L. Rollin: "Nonsense. Never heard of it."
Birgen: "Pick a window. I'll demonstrate".

GW's =I= articles

Dosdamt

You reverse engineered information on a fictional weapon? Crikey. You are clever...  ;)

So you'll be building them next....  ;)

Without the specifics of anything like the production methods, the relative technologies used to construct the weapons, what effect the Warp has on physics in the 40k universe, this is a lovely exercise in academia but since it's based in our physical realm where as far as I'm aware, 8ft tall super soldiers aren't blasting at daemons from another dimension, it's just that - academic rambling demonstrating how much super knowledge you chaps have in your relative fields.

And well done on that, by the way. It's interesting stuff and I'm genuinely impressed, you guys know *alot*.

But, can we be serious for a second - it's a fictional realm.

If I say "They use super duper heating sinks" it has as much credibility as you chaps showing the science in this world works and renders weapons useless / hot / whatever in a fictional realm.

@the OP - I like the idea of plasma treated steel = plasteel and adamantium being an as yet undiscovered super alloy. They sound cool.

-Ben
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