If I were to build a world like Game of Thrones, how would the dragons not burn their own nostrils from the heat of flames?
Same way a lighter works. See wikipedia. But to summarise, you might want to ask yourself why a lighter doesn't melt. It appears as though the flame is coming from the lighter, and yet the inside of the lighter is not burned. You can look at the mechanics and principles behind the way a lighter works and apply it to a biological creature.
So the creature may have a flammable gas that it breathes out from a special organ, and it uses another method to ignite it, on the way out.
You should be studying every kind of gas-flame fuel and how they work on a mechanical level.
EDIT: Some of this is also going to depend on what type of fire breath we're talking about--some fictional dragons give us fire from their noses, or their mouth, or both. Establish which of these you are doing and you can start to set up the mechanics for that.
jamesqf has basically given the answer in his comment to the OP.
The dragon exhales flammable gas at high pressure, that either ignites on contact with air or is lit by a spark as it leaves the dragon's maw. Or possibly even a low flashpoint gas that gets heated by the pressure of exhalation and catches fire as soon as it finds some oxygen.
Either way, as long as it's blowing at sufficiently high pressure, the heat is conducted away from the dragon, rather than towards it. It's the same principle as they use in fire breathing in circuses. See: https://youtu.be/h3czvJNTqUQ
The risk to the dragon, as to fire breathers, is when they're stopping. The decrease in pressure will cause the flame to travel back and scorch the dragon's face for a fraction of a second. In order for the above to work, the dragon needs to have a separate sac for storing fuel, that is separate from it's lungs, and a mechanism to ensure that both the fuel sac and lung pathways are not open at the same time. But even humans already have that---it's called belching.
In our world, dragons are smaller and have six legs - the bombardier beetle protects itself from heat partially by the reaction being in a thick skinned chamber, and mostly by ejecting the hot gas away from itself.
I think the term you and many others are really looking for here is hypergolic.
A hypergolic combination essentially means the two will combust on contact with one another.
They are mainly used in rocketry where it's necessary to have reliable ignition (and re-ignition) when you're pumping massive amounts of fuel and oxidizer into the engine nozzle, and because of the extreme temps & pressure (or vacuum) a regular spark plug won't cut it.
Common Hypergolic Propellants:
- Unsymmetrical dimethylhydrazine (UDMH) + nitrogen tetroxide (N$_2$O$_4$)
- Aerozine 50 + nitrogen tetroxide (N$_2$O$_4$) – Aerozine 50 is a mixture of 50% UDMH and 50% straight hydrazine (N$_2$H$_4$)
- UH 25 is a mixture of 25% hydrazine hydrate and 75% UDMH.
Hydrazine is easily my favorite, so I tried to incorporate the ones that use it, which is most of them. It's also used as a monopropellant for the Reaction Control Thrusters (RCS) in most spacecraft to control attitude (direction), because hydrazine is so reactive it will also combust all on its own just by coming in contact with an Iridium catalyst. (tho not as high energy as other reactions)
Fun fact about The Martian:
This fuel (and possibly same catalyst also?) is the same that Mark Watney stole from their MDV (Mars Descent Vehicle) to make extra water. He disassembled the rocket engine to get to the catalyst, broke it apart so as not to cause a full reaction, and dripped Hydrazine (N$_2$H$_4$) over it to break it down into ammonia, nitrogen, and hydrogen (8 H$_2$), which he funneled up a makeshift chimney to a flame to burn off the hydrogen gas (H$_2$) so it would react with the oxygen (O$_2$) in the atmosphere and combine to form water (H$_2$O), which his water reclaimer would pull out of the atmosphere and store in tanks. His oxygenator scrubbed his breath (CO$_2$) for oxygen (O$_2$) and stored it in tanks, so he needed hydrogen to make water.
Most hypergolics are very stable for long durations and stay liquid at room temperature.
Most are also famously toxic and corrosive. The people who handle them have to wear full body pressurized suits with oxygen tubes (essentially spacesuits). You can only imagine with a chemical this reactive, what would happen if you inhaled it, or touched it.
Plus, it helps that most of them are also clear and colorless like water, odorless, and tasteless. Awesome.
In movies with dragons or dragon-alike creatures (Godzilla), I've repeatedly seen when they show the up-close details of fire breathing, they show two liquids being squirted out of separate glands in the mouth, and there's no fire until the two make contact.
This is a hypergolic reaction and would not burn the dragon at all. The liquids do not need to be at a high temperature, and depending on angles of glands, the reaction could take place far away from the dragon's face.
The real issue here is the extreme toxicity and non-organic nature of these chemicals, and since these are fictional beasts I'm not sure how far you want to go before just calling it magic. There does exist some relatively non-toxic hypergolic propellants out there, and possibly ones we haven't discovered yet that are closer to organic chemistry, if you want to go that route.
Chemistry is cool again! (You're welcome) ;D
I've never been a big fan the traditional sciences, math, chemistry, all seemed drab and boring. But rockets and going to SPACE are all pretty neat, and what do you know, rocket science is actually really hard and combines nearly every type of science mankind knows of.
Plus, I was super excited to find out that this is actually a real reaction which people use daily, and hypergolic is just a freakin' cool word that everybody wants to know and use. Cheers!
There are a few possible answers to this questions that can fall along the range of fact and fiction. I will address the question with regard to several types of dragons.
1) Magic. For dragons that use magic to produce fire, the simplest answer is that the same magic that makes the fire also protects the dragons face from the heat of the flames. (See D&D Dragons).
2) Science! For the style of dragon that uses venom that combusts when exposed to air or mixing with another venom, the speed in which those fluid leave the dragons mouth cause the reaction to happen away from the dragons face. (See Reign of Fire)
3) Science again! For dragons that use a combustible gas. Once again the reaction would be happening a foot or two in front of the dragon's face because there would not be oxygen to burn within the dragon’s mouth. (See Bunsen burner/butane torches)
All of these dragons would likely be evolve for fire resistant scales, but I hope I have addressed how the sensitive parts of the face might be protected.
P.S. The GoT dragons fall into the first category.
May be they do burn their nostrils as baby dragons.
I think you can compare it to e.g. goldsmiths.
In the beginning a goldsmith has very sensitive hands, like everybody else. But due to constant work with hot metal, the fingers get a horn skin / cornea, which makes them able to touch 300-400°C hot metal rings.
This may happen in a way to dragons too. Due to spitting fire from time to time, the skin around the nostrils gets thicker and more... (i won't put the word horny here) adopted to the heat of the flames.
(Source: My wife is a goldsmith an I have seen her catching rings that were lying under a flaming torch seconds ago and then dropped)
The trick, is not minding that it hurts - Lawrence of Arabia
When you see dragons breathing fire, they are usually either angry or defending themselves, the sort of situations in which a human or any other creature might ignore a fairly significant amount of pain and lash out anyway.
For example, Smaug was livid at the thought of anyone trying to steal his gold and decided to torch Lake Town as revenge, but in the book it is stated that he had not done that sort of thing in a long time and had forgotten how good it felt. It's not canon that his snout really hurt afterwards and that was why he rarely did it, but the idea is somewhat consistent.
You know, the dragons technically dont have to be completely flame-resistant. Im doing a research project on dragonflame and I have something I call the "Bumblebee Effect." The dragon only has to be able to produce flame, but the flame has the liability to combust on its caster since the method of flame in my research is methane and hydrogen. Similar to how a dragons flame may hurt or kill it, the bumblebee cannot survive stinging an enemy. This also eliminates the arguement of "it`s faulty evolution"
In game of thrones Dragons are simply immune to fire (bolognum: no in world plausible explanation), and any person that has dragons' blood inside its body is immune to fire and heat too. Note that other characters are immune to fire/heat, but for different reasons.
So if you are asking how in Game of thrones we have living beings immune to fire, there's no explaination apart the usual "magic" argument.
Your story your rules.
If you are asking how can someone in nature be immune to fire/heat:
- no single living being is immune to fire.
- probably there's no life at all after 1000 C°.
- prolonged exposition to much heat will be damaging anyway anyone.
- carbon based living beings are made mostly by water and carbon
- waters boils at 100 C° and carbon have a plenty of various chemical reactions that happens at different temperatures.
- cells are made basically of fat which just fries below 300 C°
So possible real-world explanations:
- Actually the dragon is not touching the fire directly (combustion happens far away)
- Actually the dragon has some coolant that is going to be exausted (like water from additional glands)
- Actually the dragon is not a regular living being (no cells made of fat: it could be a robot)
- The skin and heat-related body parts are protected by something
What can protect from heat and be naturally produced? Foam! Foam is perfect for isolating from heat, and we have plenty creatures in our real world that produces foam for some reason or another (I doubt anyone tested those foams as heat insulator anyway).
Also foam can be quickly replaced to keep temperature down: assume for a second the dragon has some kind of callus that protect from heat (it can be just dead tissue or some body-produced ceramic): if we managed to keep the callus exposed enough time to heat the callus may become very hot thus starting burning the below meat, and since materials resistant to heat can also store much heat, once the callus is hot it will fry the dragon for very long time. That's why callus is a bad idea while foam is slightly better.
How do electric eels not shock themselves? How do venomous snakes and spiders and so forth not poison themselves? There are lots of real world examples where creatures have evolved to have self-protection from the dangerous and deadly things they can do. Some we understand, others we don't. Put dragons into the same category.
It might be a nice theoretical discussion for your characters, but I don't think you need to provide an explanation for it. "We don't know" is a sufficient answer.
Make it so that the dragon spews two different liquids (carried in two different sacks each on the opposite side of the mouth) that ignite when they combine. The streams of the two liquids intersect in front of the dragon and ignite at a relatively safe distance. The dragon would also of course have scales/skin on it forward facing regions that could handle the heat.
In Game of Thrones, Targaryen lineage are fire immune by magical means.
It's obviously not a physical process which protected Daenerys in Drogo's funeral pyre. She'd definitely burn (pyrolize, boil) if not for magic.
Therefore we can say that dragons in GoT universe might be fire immune by same, magical, means.