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Post by gedzilla on Apr 6, 2017 14:45:20 GMT
here ya go.
(P.s. even tho Ammonia has a better exit v, when was messing with to optimize it, it was giving me probs, and its thrust-mass ratio is horrific. water is better in that regard.
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Post by The Astronomer on Apr 6, 2017 14:54:21 GMT
Guys, new one incoming: HYDRAZINE.
Also, the pics won't come up for non-forum users. I'll repost the pictures on my imgur.
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Post by sevenperforce on Apr 6, 2017 15:02:21 GMT
One of the posters on the other forum....
Is this all assuming expansion to vacuum?
Also, are you assuming a solid-core, gas-core, or pebble-bed NTR?
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Post by The Astronomer on Apr 6, 2017 15:06:46 GMT
Solid core, and yes, it's pure vacuum. Atmospheric NTRs might gives horrible results, but I don't know about that one.
Welcome to Children of a Dead Earth forums.
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Post by gedzilla on Apr 6, 2017 15:07:07 GMT
Here is Hydrazine. its shitty. just use Decane, or Methane, or Hydrogen Deutride
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Post by sevenperforce on Apr 6, 2017 15:07:10 GMT
I expect it will be difficult to beat hydrazine for impulse density, though it is obviously not ideal for an ISRU application. I mean, I suppose with a source of water and atmospheric nitrogen, you have everything you need to synthesize hydrazine, but the chemical route might be tough.
The trick would be keeping hydrazine liquid for as long as possible in the NTR core so that most of the disassociation happens downstream, heating it up just a little more.
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Post by gedzilla on Apr 6, 2017 15:09:37 GMT
keep in mind, these are all thrown together very quickly, so with some intensive tweaking and more time, it may be possible to get something slightly better, but that version wont have too different an exit velocity.
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Post by gedzilla on Apr 6, 2017 15:10:19 GMT
and welcome sevenperforce
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Post by sevenperforce on Apr 6, 2017 15:33:21 GMT
Hydrazine is shitty? That surprises me. What's the specific impulse (I can't see anything more than a thumbnail)? What happens if you add the decomposition energy into the propellant stream after it exits the reactor core?
Per Project Rho, a pebble-bed rocket has about an 18% specific impulse advantage over a standard NERVA NTR for LH2, but I don't know if that translates to other fuels. Of course a pebble-bed NTR has never been built, unlike a NERVA. On the other hand, pebble-bed reactors are common enough.
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Post by bigbombr on Apr 6, 2017 15:38:19 GMT
I expect it will be difficult to beat hydrazine for impulse density, though it is obviously not ideal for an ISRU application. I mean, I suppose with a source of water and atmospheric nitrogen, you have everything you need to synthesize hydrazine, but the chemical route might be tough. The trick would be keeping hydrazine liquid for as long as possible in the NTR core so that most of the disassociation happens downstream, heating it up just a little more. Fluorine-dense organic fuel combustion rocket might beat hydrazine for impulse density. Though metallic hydrogen, if metastable, would beat both for impulse density and surpass hydrogen solid core NTR's.
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Post by The Astronomer on Apr 6, 2017 15:39:58 GMT
Hydrazine is shitty? That surprises me. What's the specific impulse (I can't see anything more than a thumbnail)? What happens if you add the decomposition energy into the propellant stream after it exits the reactor core? Per Project Rho, a pebble-bed rocket has about an 18% specific impulse advantage over a standard NERVA NTR for LH2, but I don't know if that translates to other fuels. Of course a pebble-bed NTR has never been built, unlike a NERVA. On the other hand, pebble-bed reactors are common enough. Exhaust velocity: 3.29 km/s Thrust: 718 kN TWR: 138 g I believe the dev has already added the decomposition energy. There have been problems with resistojet that sometimes violates the energy conservation. For example, methane resistojet is 8000% efficient.
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Post by The Astronomer on Apr 6, 2017 15:40:56 GMT
I expect it will be difficult to beat hydrazine for impulse density, though it is obviously not ideal for an ISRU application. I mean, I suppose with a source of water and atmospheric nitrogen, you have everything you need to synthesize hydrazine, but the chemical route might be tough. The trick would be keeping hydrazine liquid for as long as possible in the NTR core so that most of the disassociation happens downstream, heating it up just a little more. Fluorine-dense organic fuel combustion rocket might beat hydrazine for impulse density. Though metallic hydrogen, if metastable, would beat both for impulse density and surpass hydrogen solid core NTR's. no fluorine. Metallic H2 is probably not that near-future.
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Post by sevenperforce on Apr 6, 2017 15:47:52 GMT
Hydrazine is shitty? That surprises me. What's the specific impulse (I can't see anything more than a thumbnail)? What happens if you add the decomposition energy into the propellant stream after it exits the reactor core? Exhaust velocity: 3.29 km/s Thrust: 718 kN TWR: 138 g I believe the dev has already added the decomposition energy. There have been problems with resistojet that sometimes violates the energy conservation. For example, methane resistojet is 8000% efficient. How about HTP? High test peroxide will have a better specific impulse and a higher density than water.
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Post by The Astronomer on Apr 6, 2017 15:56:27 GMT
Guys, call in the modders.
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Post by gedzilla on Apr 6, 2017 16:23:01 GMT
Im not a modder, sorry
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