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Post by samchiu2000 on Apr 3, 2017 7:47:32 GMT
p-B11 fusion makes no neutrons, only Helium-4, so I tried modding it in as a 'chemical reaction'. Here's the result:  For further Lulz, I put this joke engine on a ship:  Did I make a mistake in the numbers somewhere? How can the rocket (especially the chamber) survive from that high temperature？ |
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Post by nerd1000 on Apr 3, 2017 8:09:02 GMT
p-B11 fusion makes no neutrons, only Helium-4, so I tried modding it in as a 'chemical reaction'. Here's the result: For further Lulz, I put this joke engine on a ship: Did I make a mistake in the numbers somewhere? How can the rocket (especially the chamber) survive from that high temperature？ Note the low working pressure (1.39 kPa) and the tiny mass flow rate (a little under half a gram per second). These conditions ensure that the engine has enough surface area to radiate the heat it absorbs. In reality that probably wouldn't work, but it seems that Qswitched overlooked the possibility of the chamber experiencing temperatures 200 times hotter than the core of the Sun and as such the thermal rocket code doesn't account for the chamber material evaporating before the heat is conducted away. |
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Post by samchiu2000 on Apr 3, 2017 8:35:56 GMT
How can the rocket (especially the chamber) survive from that high temperature？ Note the low working pressure (1.39 kPa) and the tiny mass flow rate (a little under half a gram per second). These conditions ensure that the engine has enough surface area to radiate the heat it absorbs. In reality that probably wouldn't work, but it seems that Qswitched overlooked the possibility of the chamber experiencing temperatures 200 times hotter than the core of the Sun and as such the thermal rocket code doesn't account for the chamber material evaporating before the heat is conducted away. Alright I see~ |
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Post by The Astronomer on Apr 3, 2017 9:28:25 GMT
IT LITERALLY HAPPENS. THANKS, GUYS, THIS IS THE BEST TIME IN MY AWFUL LIFE EVER.
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Post by RiftandRend on Apr 3, 2017 9:58:12 GMT
I sure hope not, that'd revolutionize our propulsion if we could handle that insane heat somehow. Well, that's really the crux of the issue.  Two conditions are inherent to a rocket with both high thrust and high exhaust velocity: The required engine power is ludicrously high, and there is insufficient propellant mass flow to use it for cooling. There are many ways to use nuclear fuels to generate the required power (the simplest being nukes), but even if you can do it you're left with the problem of how to couple this nuclear inferno to your ship in a way that pushes it around without promptly vaporizing it. There are various proposed solutions for various power levels, so I'm not saying it's impossible, but I think in general "how do we make this not vaporize instantly" is just as big a design issue as "how do we make it generate the required power". You can just use a separate cooling system if regenerative cooling isn't an option. If you have enough power to run the engine you definitely have enough to cool it too. |
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Post by RiftandRend on Apr 3, 2017 10:12:50 GMT
Fusion without the power requirements is stupidly overpowered. Off to TRAPPIST-1!   Diamond seems to be up and away the best material for the thruster walls. Good yield strength, high melting point and a low thermal expansion coefficient are too hard for boron to beat. Graphene also works.  |
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Post by nerd1000 on Apr 3, 2017 10:18:47 GMT
Note your engines-on thermal signature of 3.6*10^10 Yottawatts. That's about 1/380th of the sun's total power output. Doc brown ain't got nothing on us.
Edit: This is actually closer to 10^8 times more power than the sun, and I'm a fool who can't read.
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Post by samchiu2000 on Apr 3, 2017 10:18:54 GMT
BTW nerd1000 why the ignition temperature of the reaction is only 10000k? Is that because it is the highest limit set by the game? |
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Post by samchiu2000 on Apr 3, 2017 10:22:57 GMT
Note your engines-on thermal signature of 3.6*10^10 Yottawatts. That's about 1/380th of the sun's total power output. Doc brown ain't got nothing on us. I think that the heat signal can be detected even if you are at the another end of the milky way... |
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Post by nerd1000 on Apr 3, 2017 10:28:35 GMT
BTW nerd1000 why the ignition temperature of the reaction is only 10000k? Is that because it is the highest limit set by the game? No, I arbitrarily chose 10,000K because I couldn't find a source for p-B11 fusion temperature (in fact it seems that p-B11 cannot sustain a fusion reaction by sheer heat, as the plasma will lose more energy as X-rays due to Bremsstrahlung than the reaction itself produces). I calculated the 'heat of formation' of the fuel by converting the fusion energy (8.7 MeV) to joules and multiplying that by avogadro's number to get the energy per mole of reactant fused. I think the biggest flaw with this 'hackjob' fusion torch is that it assumes all fusion fuel is consumed. In practice it seems unlikely that any reactor could get all of the fuel to fuse before it's ejected through the nozzle, so the possible power output and exhaust velocity should be much lower than we can achieve with this. |
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Post by RiftandRend on Apr 3, 2017 10:31:32 GMT
Note your engines-on thermal signature of 3.6*10^10 Yottawatts. That's about 1/380th of the sun's total power output. Doc brown ain't got nothing on us. I think that the heat signal can be detected even if you are at the another end of the milky way... This is a good solution to the stealth in space debate. Just shine your fusion flashlight around to illuminate them. |
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Post by nerd1000 on Apr 3, 2017 10:36:23 GMT
I think that the heat signal can be detected even if you are at the another end of the milky way... This is a good solution to the stealth in space debate. Just shine your fusion flashlight around to illuminate them. It's actually a lot more power than the sun makes (solar power output is around 380 YW, I got confused), so obviously my maths is wrong or COADE cannot handle the raw powah!!! of my mega-fusion torch and is getting the maths wrong itself. Edit: COADE seems to be at fault here. I calculated the total power of RiftandRend's Torchdrive and got 18.2 TW, so it looks like the game is getting the maths for its heat signature calculations very wrong. I doubt it was designed to handle the small exhaust mass and absurdly high temperatures, so maybe it's to be expected. |
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Post by samchiu2000 on Apr 3, 2017 10:37:04 GMT
BTW nerd1000 why the ignition temperature of the reaction is only 10000k? Is that because it is the highest limit set by the game? No, I arbitrarily chose 10,000K because I couldn't find a source for p-B11 fusion temperature (in fact it seems that p-B11 cannot sustain a fusion reaction by sheer heat, as the plasma will lose more energy as X-rays due to Bremsstrahlung than the reaction itself produces). I calculated the 'heat of formation' of the fuel by converting the fusion energy (8.7 MeV) to joules and multiplying that by avogadro's number to get the energy per mole of reactant fused. I think the biggest flaw with this 'hackjob' fusion torch is that it assumes all fusion fuel is consumed. In practice it seems unlikely that any reactor could get all of the fuel to fuse before it's ejected through the nozzle, so the possible power output and exhaust velocity should be much lower than we can achieve with this. I see (again )~ BTW is it possible to make NSWR? Although i don't think it is likely to produce because it produce neutron... |
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Post by RiftandRend on Apr 3, 2017 11:01:26 GMT
The reaction definitions might also be violating conservation of mass. 23 AMU in 24 AMU out.
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Post by nerd1000 on Apr 3, 2017 11:14:42 GMT
The reaction definitions might also be violating conservation of mass. 23 AMU in 24 AMU out. Hydrogen is H2, so we have 2x11 + 2x1 = 24 AMU going in. If hydrogen were monatomic I wouldn't have defined the reaction with two boron atoms. |
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