Heat vs. Time

[Signo]

Hi all,

I searched for a previous thread with this question but I could not find one, so here I am with my question: how does heat get absorbed (not dissipated) by components? Is there a limit temperature where the heat absorbtion starts for each part? It is better to have a 1 sec temperature spike of (e.g.) 3400° or to cook slowly for half an hour at 3000°? (or if you prefer, if I put my oven at 220° how long it will take for my aerobrakes to cook till explosion?)

Has anybody got a clue about this?

EDIT: Didn't notice 1.0.3 was out with maybe new questions, so feel free to ignore me.

Edited June 23, 2015 by Signo
1.0.3

[NathanKell]

1.x uses actual honest-to-goodness kilowatts and kilojoules. What matters is the flux (in kW) that is applied to the part; the total energy applied in then that * seconds, i.e. kJ.

[Signo]

I see, thank you.

So, as far as I understand, it works exactly like a microwave oven and the more energy the parts do absorb the more they are susceptible to explosions and the "limit temperature" we can see in the parts description is a "soft" ceiling. And spikes should be affordable while long term overcooking might be dangerous.

Which is the most common way to calculate the amount of the energy flux generated?

Is there any "public" table with the amount of kJ the parts can absorb before exploding?

The energy is continuously absorbed/dissipated or are there some triggers?

[NathanKell]

I'm not sure what you mean by limit temperature.

All parts have a "max temperature" and if they exceed that they explode.

As of 1.0.3, parts now have two temperatures to track: internal and skin. They have two max temperatures that can be set independently in the cfg (but if the skinMaxTemp is unspecified it defaults to the regular maxTemp).

If you turn on Alt-F12->Physics->Thermal->Display thermal data, you can see all the part stats during flight when you right-click on a part.

Parts are subject to certain fluxes, and they have thermal masses (how many kilojoules it takes to raise temperature one kelvin). You plop 1000kJ (say, 100kW for 10 seconds) into a part with a thermal mass of 1000, and it gets 1 kelvin hotter.

[Signo]

Ehm, the concept of calories and energy is clear to me.

It is not clear how can I calculate how many kJ are produced in an energy flux generated by my 236t lander falling through Eve atmo at 2800m/s at an average altitude of 70000m and how can this effect my poor aerobrakes.

We maybe need a wind tunnel at KSC.

However I think I can go on with this doubt still in place. Thank you.

Edited June 23, 2015 by Signo

[tutike2000]

Well, it can't be more than 236 * 2800 * 2800 kJ, assuming the game respects conservation of energy.

Which it probably doesn't.

I don't think there's any tool out there to calculate your reentry heat. The best you can get is trying it out 'for real' in sandbox + HyperEdit.