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Post by Fgdfgfthgr on Jan 29, 2018 4:44:36 GMT
As we all known, the laser stars(if you build them correctly) has been the ultimate CDE warship for quite a while. In reality, I really don't think laser star could be the real dominator of the battlefield. For 3 reasons: 1. CDE ship's generator produces too much power in case of both space and weight. You can produce more than 10GW with only around 100t of weight. That's quietly negligible compared to fuel tanks or even cannons. Of course, their size is huge, but laser star always huge because you need to place the huge radiator. I don't know how reactor in real life like, but as far as I know, they can't even produce 2GW with 1000t weight and output temperature surely lower than 2450K.
2. CDE has no structure stress, so you can build 3mm thick radiators that withstand 10G acceleration. That's the most important point. If we involve the structure stress while accelerating, laser star will have to build thicker radiator with stronger and denser materials. That will force them to add fuel tank and increase the cost of laser star.
3. AI does not know to ignore range while against a laser star (except striker AI).
For now, the game solves laser star by decreasing the efficiency of lasers. But can't we find some more realistic ways?
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Post by AdmiralObvious on Jan 29, 2018 5:37:31 GMT
If there was a more reliable way to map out how radiators work, whilst heated, as well as the result of their structural strength, WHILE ALSO factoring the fact that radiators would collapse when you accelerate too fast, it would quite significantly nerf the entire concept of the laser jellyfish.
We assume that structural capacity, in game, always remains the same regardless of temperature state of the matter (such as diamond/graphite(ene)) when in reality, the material would behave significantly differently once heated to certian points.
If we were able to successfully model all those missing parts, the laser jelly would probably be significantly bulkier, but probably still a viable option.
We should also take another look at the whole 10 1MW laser beating the one 10MW laser, as that seems to be another staple of the CDE laser meta.
If structure stress would be included on radiators, I'd guess we can also install supports around the radiator if we still wanted to keep nanometer thick radiators.
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Post by apophys on Jan 29, 2018 6:56:15 GMT
1. CDE ship's generator produces too much power in case of both space and weight. You can produce more than 10GW with only around 100t of weight. That's quietly negligible compared to fuel tanks or even cannons. Of course, their size is huge, but laser star always huge because you need to place the huge radiator. I don't know how reactor in real life like, but as far as I know, they can't even produce 2GW with 1000t weight and output temperature surely lower than 2450K. 2. CDE has no structure stress, so you can build 3mm thick radiators that withstand 10G acceleration. That's the most important point. If we involve the structure stress while accelerating, laser star will have to build thicker radiator with stronger and denser materials. That will force them to add fuel tank and increase the cost of laser star. 1. 100 kW/kg is not that unrealistic. If you don't think you can get it with nuclear fission, you can at least get it with solar thermophotovoltaic. See here: toughsf.blogspot.com/2017/11/advanced-solar-energy-in-space-part-i.html2. Or you can use droplet/bead radiators and not worry about structure at all. I'm a fan of liquid boron encapsulated in tungsten.
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Post by Fgdfgfthgr on Jan 29, 2018 7:03:14 GMT
apophys although solar thermal can be light, they are huge in size and does not work well after Duna Mars. 2. Yes, but that does not prove I am wrong...This alternative chose would be interest.
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Post by Fgdfgfthgr on Jan 29, 2018 7:07:14 GMT
If there was a more reliable way to map out how radiators work, whilst heated, as well as the result of their structural strength, WHILE ALSO factoring the fact that radiators would collapse when you accelerate too fast, it would quite significantly nerf the entire concept of the laser jellyfish. We assume that structural capacity, in game, always remains the same regardless of temperature state of the matter (such as diamond/graphite(ene)) when in reality, the material would behave significantly differently once heated to certian points. If we were able to successfully model all those missing parts, the laser jelly would probably be significantly bulkier, but probably still a viable option. We should also take another look at the whole 10 1MW laser beating the one 10MW laser, as that seems to be another staple of the CDE laser meta. If structure stress would be included on radiators, I'd guess we can also install supports around the radiator if we still wanted to keep nanometer thick radiators. I strongly suspense there will be no such system to simulate temperate cause behave change of materials. As it's too hard to simulate. (Different material behaves differently when temperature rasing.)
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Post by bigbombr on Jan 29, 2018 7:37:42 GMT
As we all known, the laser stars(if you build them correctly) has been the ultimate CDE warship for quite a while. In reality, I really don't think laser star could be the real dominator of the battlefield. For 3 reasons: 1. CDE ship's generator produces too much power in case of both space and weight. You can produce more than 10GW with only around 100t of weight. That's quietly negligible compared to fuel tanks or even cannons. Of course, their size is huge, but laser star always huge because you need to place the huge radiator. I don't know how reactor in real life like, but as far as I know, they can't even produce 2GW with 1000t weight and output temperature surely lower than 2450K. 2. CDE has no structure stress, so you can build 3mm thick radiators that withstand 10G acceleration. That's the most important point. If we involve the structure stress while accelerating, laser star will have to build thicker radiator with stronger and denser materials. That will force them to add fuel tank and increase the cost of laser star. 3. AI does not know to ignore range while against a laser star (except striker AI). For now, the game solves laser star by decreasing the efficiency of lasers. But can't we find some more realistic ways? 1) Already adressed by Apohpys 2) Laserstars typically have low (10-20 mgee) acceleration, I actually suspect structural integrity might be a bigger nerf to NTR propelled 'gunships'. For keeping radiators intact under acceleration, you can always use guy-wires. 3) Agresive AI also ignores range. Doesn't matter if it takes dozens of seconds for rounds to arrive (and MPDTs have recently proven to be useful for dodging at longer ranges). I've been asking about more detailed radiators (heat gradients, coolant criticality & pressure, actuator mass, ...) for a while now. They might be the only credible way of nerfing lasers (though I heard the frequency doubling might be overly optimistic in efficiency?), as IRL fiber lasers have 40+% efficiency while having an M² close to 1 (while ingame, we can never get M² under 3). Also keep in mind that laser ablation is borked (ingame, weak lasers are overpowered because the game doesn't model armour radiating away heat, while powerful lasers are underpowered because there seems to be a maximum ablation speed for each material, ven if you're laser has an infinitely high intensity). Furthermore, the game doesn't even take lasers beyond 10 Mm into account, nor do we have pulsed lasers and FELs. So in my opinion, while power generation and radiators are simplified and perhaps on the optimistic side, lasers are underestimated by the game.
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Post by Kerr on Jan 29, 2018 10:16:05 GMT
Is this... a laser discussion? ( ͡° ͜ʖ ͡° ) First of reactors: festkoerper-kernphysik.de/dfr.pdfA 2 meter cube producing 1GW of power Laser in CDE are OP in their own right: -High outlet temperatures -High power to weight ratios (laser power per mass) -Overly optimistic frequency doubling Frequency doubling can reach 88% efficiency out a working temperature of... 300K www.osapublishing.org/oe/abstract.cfm?uri=oe-16-3-1546Diode pumped fiber lasers can currently reach 40% efficiency with near-diffraction limited beams, but they use diode operating at slightly above room-temperature,the good thing is that frequency doubling not necessarily produces waste heat, the unconverted light can be get rid of via beam dump. Power to weight also plays a very important role, For example Apophys laser produces 11kW for every kilogram of beam generator. Diode pumped fiber can't achieve this performance yet but it based on some research they could actually reach power to weight ratios in the order of 10kW/kg. A phase-locked GaAs diode array producing diffraction-limited 800nm beams operate at 40% efficiency including heat pumps and has a outlet of 1200K while also sporting 5-10kW/kg. A diffraction-limited 800 nm beam has the same divergence as a M²=3 266nm beam. So you pretty much can replicate the deep fryer with a 2x 100MW 10t reactors instead of 2x 1GW 10t reactors if it turns out that CDE reactors are hyper optimistic. 31% for Ce:LFF range using two frequency doublers. Modded CDE lasers aren't that far fetched actually.
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Post by jtyotjotjipaefvj on Jan 29, 2018 11:55:47 GMT
A few nitpicks on that design: it's 1 GW of thermal power, meaning about 160 MW electric with our in-game thermocouples. The coolant outlet is also just 1325 K, and that would be the outlet of the inner coolant loop for a thermocouple system, as far as I can tell (source: link) This means radiator area and mass would be way bigger than we get from our current 2500 K reactors. Also, apparently nobody has built one yet so I'd take the 2 meter cube with a grain of salt. Either way, our reactors are mostly thermocouple by volume anyway so I'm not sure if this will be a huge improvement regardless. At least it will be more fuel-efficient if nothing else.
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Post by Kerr on Jan 29, 2018 12:10:10 GMT
A few nitpicks on that design: it's 1 GW of thermal power, meaning about 160 MW electric with our in-game thermocouples. The coolant outlet is also just 1325 K, and that would be the outlet of the inner coolant loop for a thermocouple system, as far as I can tell (source: link) This means radiator area and mass would be way bigger than we get from our current 2500 K reactors. Also, apparently nobody has built one yet so I'd take the 2 meter cube with a grain of salt. Either way, our reactors are mostly thermocouple by volume anyway so I'm not sure if this will be a huge improvement regardless. At least it will be more fuel-efficient if nothing else. Yes, but why would you use thermocouples? The design Apophys mentioned using solar thermal power uses thermovoltaics. They can easily achieve efficiencies reaching 80% with enough min-maxing. On the flip side; look at NTR's, their thermal output could just as well power thermovoltaics just as a normal reactor.
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Post by jtyotjotjipaefvj on Jan 29, 2018 12:44:13 GMT
A few nitpicks on that design: it's 1 GW of thermal power, meaning about 160 MW electric with our in-game thermocouples. The coolant outlet is also just 1325 K, and that would be the outlet of the inner coolant loop for a thermocouple system, as far as I can tell (source: link) This means radiator area and mass would be way bigger than we get from our current 2500 K reactors. Also, apparently nobody has built one yet so I'd take the 2 meter cube with a grain of salt. Either way, our reactors are mostly thermocouple by volume anyway so I'm not sure if this will be a huge improvement regardless. At least it will be more fuel-efficient if nothing else. Yes, but why would you use thermocouples? The design Apophys mentioned using solar thermal power uses thermovoltaics. They can easily achieve efficiencies reaching 80% with enough min-maxing. On the flip side; look at NTR's, their thermal output could just as well power thermovoltaics just as a normal reactor. That sounds even worse for a reactor. First, you'd need to radiate 1 GW @ 1325 K from your emitter. That would already be one gigantic radiator. Then you'd need the photovoltaic receiver next to it, which apparently needs to be kept at 270 K. So you'd need another radiator that needs to get rid of a few hundred MW's at 270 K in addition to the photovoltaic emitter. I don't have exact numbers but carrying around a few extra football fields in radiators certainly sounds very inconvenient. Thanks to the low exit temperature of the reactor, you'd likely lose a lot of power density to the huge emitter required, compared to the 3000 K example in the blogpost linked by Apophys, and it was already only 6 kW/kg. The skewed radiation spectrum might screw up efficiency even further, though I can't be bothered to look that up right now.
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Post by Kerr on Jan 29, 2018 13:03:41 GMT
Yes, but why would you use thermocouples? The design Apophys mentioned using solar thermal power uses thermovoltaics. They can easily achieve efficiencies reaching 80% with enough min-maxing. On the flip side; look at NTR's, their thermal output could just as well power thermovoltaics just as a normal reactor. That sounds even worse for a reactor. First, you'd need to radiate 1 GW @ 1325 K from your emitter. That would already be one gigantic radiator. Then you'd need the photovoltaic receiver next to it, which apparently needs to be kept at 270 K. So you'd need another radiator that needs to get rid of a few hundred MW's at 270 K in addition to the photovoltaic emitter. I don't have exact numbers but carrying around a few extra football fields in radiators certainly sounds very inconvenient. Thanks to the low exit temperature of the reactor, you'd likely lose a lot of power density to the huge emitter required, compared to the 3000 K example in the blogpost linked by Apophys, and it was already only 6 kW/kg. The skewed radiation spectrum might screw up efficiency even further, though I can't be bothered to look that up right now. Scroll down:"System power density should be close to 119kW/kg, though realistically it will be lower." Performance of 50kW/kg is fairly feasible using this technique.
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Post by jtyotjotjipaefvj on Jan 29, 2018 13:25:28 GMT
That sounds even worse for a reactor. First, you'd need to radiate 1 GW @ 1325 K from your emitter. That would already be one gigantic radiator. Then you'd need the photovoltaic receiver next to it, which apparently needs to be kept at 270 K. So you'd need another radiator that needs to get rid of a few hundred MW's at 270 K in addition to the photovoltaic emitter. I don't have exact numbers but carrying around a few extra football fields in radiators certainly sounds very inconvenient. Thanks to the low exit temperature of the reactor, you'd likely lose a lot of power density to the huge emitter required, compared to the 3000 K example in the blogpost linked by Apophys, and it was already only 6 kW/kg. The skewed radiation spectrum might screw up efficiency even further, though I can't be bothered to look that up right now. Scroll down:"System power density should be close to 119kW/kg, though realistically it will be lower." Performance of 50kW/kg is fairly feasible using this technique. Unless you pump the reactor exit temperature to that 5300 K, you won't get any power out of that setup. At 1325 K, our emitter would be around 260 times larger and heavier than the 5300 K one. Additionally, at 1325 K, we get a measly 5.5 W/m² of 545nm radiation, instead of the 10 MW/m² used to obtain the numbers in the version I found by scrolling down a little, so our photovoltaic receiver would be largely useless for the emission spectrum. You can't just apply the numbers of the best case scenario to every situation, there are more variables at play here. Edit: source for the blackbody spectra: www.spectralcalc.com/blackbody_calculator/blackbody.php
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Post by Enderminion on Jan 29, 2018 14:58:36 GMT
most laserstars don't have side armour, I got nukes past a Beholders armour/laser cap and killed it.
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Post by Kerr on Jan 29, 2018 16:45:56 GMT
Scroll down:"System power density should be close to 119kW/kg, though realistically it will be lower." Performance of 50kW/kg is fairly feasible using this technique. Unless you pump the reactor exit temperature to that 5300 K, you won't get any power out of that setup. At 1325 K, our emitter would be around 260 times larger and heavier than the 5300 K one. Additionally, at 1325 K, we get a measly 5.5 W/m² of 545nm radiation, instead of the 10 MW/m² used to obtain the numbers in the version I found by scrolling down a little, so our photovoltaic receiver would be largely useless for the emission spectrum. You can't just apply the numbers of the best case scenario to every situation, there are more variables at play here. Edit: source for the blackbody spectra: www.spectralcalc.com/blackbody_calculator/blackbody.phpNow you only have to add filters to the equation. Have a diffraction grating and reflect every wavelength besides 545nm back to the black body.
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Post by jtyotjotjipaefvj on Jan 29, 2018 17:05:57 GMT
Unless you pump the reactor exit temperature to that 5300 K, you won't get any power out of that setup. At 1325 K, our emitter would be around 260 times larger and heavier than the 5300 K one. Additionally, at 1325 K, we get a measly 5.5 W/m² of 545nm radiation, instead of the 10 MW/m² used to obtain the numbers in the version I found by scrolling down a little, so our photovoltaic receiver would be largely useless for the emission spectrum. You can't just apply the numbers of the best case scenario to every situation, there are more variables at play here. Edit: source for the blackbody spectra: www.spectralcalc.com/blackbody_calculator/blackbody.phpNow you only have to add filters to the equation. Have a diffraction grating and reflect every wavelength besides 545nm back to the black body. I'm not sure if you know what you're talking about here? That means a ridiculous decrease in the emitter efficiency. Let's say we let through everything between 500 and 600 nm to allow more than one photon through at a time. For the 1325 K emitter, this means .79 W/m²/sr, or about 2.5 W/m² radiant emittance for the blackbody emitter. Compared to the full spectrum emittance, 170 kW/m², we're reflecting back around 69,000 times more irradiance than we're letting through, meaning our radiator has an efficiency of 0.0014%. This means the emitter would be roughly 18 million times heavier and larger than the one described in the blog. The emitter would need to have a surface area of 400 million square meters, or 400 km². I'm sure we could still pull off at least 30 kw/kg off of that!
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