NathanKell

[1.1.3] RealHeat (Minimalist) v4.3 July 3

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RealHeat

At present a minimalist version of the long-awaited RealHeat

by NathanKell and ferram4

This is a simple mod to correct some temperature-related things in KSP's thermal model. Later it will replace things wholesale, building on the work of goozeman and SRFirefox in addition to those above.

Features

 

  • Calculates a shock temperature based on atmospheric composition and velocity.
  • Calculates gamma based on atmospheric composition and velocity.
  • Recalculates background radiation temperature (and the density-based interpolation factor used there and in other things) based on the above.



Installation
Extract RealHeat folder and ModularFlightIntegrator folders to GameData.
Note: Includes and requires ModularFlightIntegrator by sarbian, used under license.
 

Download
GitHub

License: CC-BY-SA

 

Changelog:

v4.3

* Update to KSP 1.1.3

v4.2

* Lower convective coefficient at low density and velocity (we were overestimating convection then).

v4.1

* Update for KSP 1.1.2.

v4

* Update for KSP 1.1.
* Use KSP 1.1 feature of changing convective coefficient rather than shock temp when varying convection behind attached and detached shocks. All these are stated in the cfg for tuning.
 

v3

* Fix an issue with too-high background radiation temperature. This prevents blowups for low-temperature parts, but it may understate radiative heating during lunar-plus reentries. Pending 1.1 for a workaround KSP-side.

 

v2
* Updated to KSP 1.0.5.
* Removed AeroFX bits (done by stock now).

 

v1.1
Supports changing aeroFX now. Defaults to making it intense down low, so you can set the normal aeroFX settings to much lower scaling to not have flames on ascent. Supports aeroFXdensityExponent1 (default = 2.0) and aeroFXdensityMult1 default = 90), and the final density passed to aeroFX will be (density^aeroFXdensityExponent1 * aeroFXdensityMult1 + density^PhysicsGlobals.aeroFXDensityExponent) instead of just density^PhysicsGlobals.aeroFXDensityExponent.

v1.0 Initial Release

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I have made changes to stock physics variable to compensate for playing on a resized system. How does this mod better adapt the system we have to that? Would I need to revert or rework any particular variables I may have changed in using the stock system. Thanks!

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Nope! This can peacefully coexist with whatever Starwaster comes out with for KSP 1.0.4.

However, this will give you real shock temperatures, which means things will not be very hot at all except in RSS or 10x (or 6.4x, where reentry will be 35% as hot, give or take, as real life).

Svm420: this is broadly equivalent to setting machtempscalar to 1 and machtempexponent to 1, for Kerbin reentries. However, it also somewhat increases radiative heat from shockwaves, but not so much as to be noticeable on <10km/sec reentries.

Note that this was calibrated using RSS and RO's physics parameters.

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I'm guessing that this renders Deadly Reentry obsolete?

To weigh in on this too, the next version of Deadly Reentry - due to changes in stock thermodynamics which meet the needs that I had for DRE - will limit its handling of heating to configuration tweaks to the stock system. The next update after that would likely have any Real Heat specific tweaks, IF I think they're necessary for either compatibility or to take advantage of Real Heat, but I haven't yet had a chance to play with RH so I'm not sure if I'll need or want to.

Now, that said, Deadly Reentry isn't just about heat. Don't forget, there's G forces! Things catching fire! (insert Beavis voice screaming FIRE! FIRE!). Maybe room for other things like cabin heating or something... but that's probably going out of scope so maybe not.

But yeah, as far as implementing the heating side of things, I'm pretty happy with where things are at. (currently, DRE isn't even making use of Modular Flight Integrator and I'm not sure it will need to)

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Will this system eventually simulate heat production in the ship from things other than engines? (such as waste heat from using electric charge, Kerbal metabolism, mechanical systems, etc.)

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Starwaster: RealHeat kinda by definition will be fairly useless for small solar systems unless you modify the resultant shock temperatures somehow--it'll report a shock temperature of only about (velocity) K during Kerbin reentries, indeed somewhat lower until you hit 10km/sec.

Later when RealHeat becomes more worthy of the name (by doing what BigFatStupidHead mentions, and by redoing convection in conjunction with FAR), well, that'd be different.

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Starwaster: RealHeat kinda by definition will be fairly useless for small solar systems unless you modify the resultant shock temperatures somehow--it'll report a shock temperature of only about (velocity) K during Kerbin reentries, indeed somewhat lower until you hit 10km/sec.

Later when RealHeat becomes more worthy of the name (by doing what BigFatStupidHead mentions, and by redoing convection in conjunction with FAR), well, that'd be different.

Well I just did a run through of Mun -> Kerbin reentry and it did just fine. I did panic a little when the heat shield didn't ablate as fast as I thought it should... until I remembered it was the SDHI shield which isn't supposed to ablate as much. So, at the very least it's not interfering that I can see.

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Oh oh wow I was wondering what had happened to this

However, this will give you real shock temperatures...

Eggggcellent

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Great!:DAny adjustment needed to use with 6.4x?

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Great!:DAny adjustment needed to use with 6.4x?

I would second that question.

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If you use this with 6.4x, you'll get lower shockwave temps as I mentioned (since orbital velocity is a fair bit lower). Whether that makes reentry too easy or not is up to your preference.

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It's coming :)

Edited by Svm420
He knows...

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Well now we need a recompile for MFI 1.1.


The following assembly referenced from /home/mcfadds2/.local/share/Steam/steamapps/common/Kerbal Space Program/GameData/RealHeat/Plugins/RealHeat.dll could not be loaded:
Assembly: ModularFlightIntegrator (assemblyref_index=3)
Version: 1.0.0.0
Public Key: (none)

He knows; it's coming.

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I tried 6.4x Kerbin LKO reentry and here's the result.

Ap:200km Pe:55km with FAR 0.15.3.1

MK1-2 Pod (with modified stockalike DRE heatshield)

jJSvAzj.png

MK1 Pod (I modified the .cfg to make it have a stock 1.25m heatshield)

0QGtfiP.png

It seems that the ablator burned up too fast:(It only burns 1/4 of AblativeShielding in KSP1.0.2 with DRE and FAR

Any suggestions to modify Physics.cfg?I want it to burn slower as DRE does

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I tried 6.4x Kerbin LKO reentry and here's the result.

Ap:200km Pe:55km with FAR 0.15.3.1

MK1-2 Pod (with modified stockalike DRE heatshield)

http://i.imgur.com/jJSvAzj.png

MK1 Pod (I modified the .cfg to make it have a stock 1.25m heatshield)

http://i.imgur.com/0QGtfiP.png

It seems that the ablator burned up too fast:(It only burns 1/4 of AblativeShielding in KSP1.0.2 with DRE and FAR

Any suggestions to modify Physics.cfg?I want it to burn slower as DRE does

1/4 is way too low and not what I aimed for with stock+DRE alone. (too much FAR drag early on maybe...)

I'd say the results you got here should be satisfactory. You definitely don't want something that's going to last through 2-3 reentries unless it's an advanced shield or non-ablative.

That said, try a slightly steeper angle (lower periapsis)

55km would be full RSS. 20km would be stock sized. So somewhere inbetween.

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I don't mean to ninja your thread, but seeing all of these "realistic" mod-devs here (looking at you Nathan/Star) I just want to pose a real quick question. Without utilizing a heat shield, should it be feasible for an SSTO or any lifting-body configuration to re-enter in 64k? I don't normally play with scaling configs. I've managed to put an SSTO into orbit after many many attempts and rebuilds. But I can't bring the thing down safely. A Stock Mk 1-2 command pod with a stock 2.5m heat shield makes it through just barely. Without providing to much more info and derailing this discussion to far, does that sound about right? Obviously it SHOULD be possible (We had STS program in real life afterall) so I'm under the impression that its simply a stock parts limitation. I'm tempted to change some temp limits on stock parts or play with the heat difficulty slider a bit, but I wanted to hear from the "pros" first. I should probably add I play with the latest FAR install as well, but I don't have DRE. Maybe that is the problem?

Edited by Arsonik

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Starwaster: Thanks for your advice. I change the reentry to Pe 30km with NathanKell's RO physics.cfg and it works fine. However it still only burns 1/4 of Ablator, maybe a steeper angle is needed:)

NathanKell: Thanks for your Physics.cfg, it works fine. Which line should I edit if I want a bit hotter reentry?

Here's the result with RO_Physics.cfg and steeper reentry

Seems that it's a bit cooler for 6.4x

Ap:200km Pe:30km

MK1-2Pod

zJloQPN.png

MK1Pod

c8Q4gP2.png

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You could increase the convectionFactor -- that will increase heat transferrence without increasing shock temp.

Burning 1/4 your ablator is _tons_--Mercury burned maybe 1-2kg (1-2 units of Ablator) on reentry, and Gemini burned something like 1/6th of its (IIRC). The reason for this is twofold: (1) safety, you want one heck of a margin, and (2) loss rate (and thus heat loss) is proportional to the amount of ablator, so the more ablator you bring, the faster it will ablate and the more cooling you get. With very high heat fluxes you can need to burn off quite a bit of ablator, proportionally, for those few seconds of q"max, and to get that rate, you may need to pack a lot of ablator.

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You could increase the convectionFactor -- that will increase heat transferrence without increasing shock temp.

Burning 1/4 your ablator is _tons_--Mercury burned maybe 1-2kg (1-2 units of Ablator) on reentry, and Gemini burned something like 1/6th of its (IIRC). The reason for this is twofold: (1) safety, you want one heck of a margin, and (2) loss rate (and thus heat loss) is proportional to the amount of ablator, so the more ablator you bring, the faster it will ablate and the more cooling you get. With very high heat fluxes you can need to burn off quite a bit of ablator, proportionally, for those few seconds of q"max, and to get that rate, you may need to pack a lot of ablator.

The problem with that is that on lunar returns you still get a huge majority of ablator intact and that doesn't sound right for Apollo missions. Apollo's shield was only capable of one return with one skip-out during reentry.

I've also always found it a little odd with the ablator module that ablation is proportional to amount since ablation should only occur at the surface, or within a few centimeters of it.

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My understanding was that the Apollo shield, too, was incredibly overengineered--that it used something like 1/3 its ablator on descent.

The amount proportionality dates back to goozeman's suggestion, but perhaps you're right that it should be surface area covered by ablator * (some thickness factor).

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just tried a shallow entry in rss with real heat (and realism overhaul, and a ton of other things) with just a mk1 capsule, reaction wheel and heat shield. simulated the craft with a kerbal construction time orbital start @135 km, and dropped periapsis to ~120 km before ditching the thrust stage and letting friction do it's job.

touchdown after 1h with remaining 392 of 400 ablator points - similar to what i remember from 0.9 dre runs with similar setups. which from how i understand the posts above sounds like this is the expected performance?

with stock heating and before ro (not sure if that changed anything relevant there) the craft burned up above 100km, iirc... so i think i am finally getting to the point where i can play ksp again :)

thanks for all these real-series mods, they are very much appreciated!

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My understanding was that the Apollo shield, too, was incredibly overengineered--that it used something like 1/3 its ablator on descent.

The amount proportionality dates back to goozeman's suggestion, but perhaps you're right that it should be surface area covered by ablator * (some thickness factor).

The impression I got from reading NASA's documents on AVCOAT testing was that it seemed like the burn through rate was fairly consistent with a range of ablation tempertures, incoming flux and char erosion due to airflow across the shield.

Maybe take a look at this: http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA308517

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