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Post by bigbombr on Dec 29, 2016 13:14:28 GMT
The calculator requires a non-zero atmosphere and also check what the ambient temperature should be. Obviously a radiator is more vulnerable to melt than an equivalent thickness of hull plating, which may be at single digit absolute temperatures (default is 300K) It would be nice if we could actively cool (parts of or the entire) hull for laser resistance or thermal stealth.
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Post by morrigi on Jan 2, 2017 15:26:47 GMT
The calculator requires a non-zero atmosphere and also check what the ambient temperature should be. Obviously a radiator is more vulnerable to melt than an equivalent thickness of hull plating, which may be at single digit absolute temperatures (default is 300K) It would be nice if we could actively cool (parts of or the entire) hull for laser resistance or thermal stealth. You'd need massive heat sinks for that.
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Post by bigbombr on Jan 2, 2017 15:48:00 GMT
It would be nice if we could actively cool (parts of or the entire) hull for laser resistance or thermal stealth. You'd need massive heat sinks for that. Depends on how much juice you're getting hit with. The main danger of lasers is not that they project large amounts of energy, it's that they focus this on a small area. An active cooling system would allow you spread out that heat and radiate more of it away (hopefully keeping the temperature low enough to keep your armour from ablating).
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Post by michalo on Jan 3, 2017 16:21:51 GMT
You'd need massive heat sinks for that. Depends on how much juice you're getting hit with. The main danger of lasers is not that they project large amounts of energy, it's that they focus this on a small area. An active cooling system would allow you spread out that heat and radiate more of it away (hopefully keeping the temperature low enough to keep your armour from ablating). I think that problem is not with heat sinks (it's still only 340 MW of power, you can use radiators to remove that heat), it's with transmission of heat. For smaller lasers that might work, (although you would probably need absurdly big pumps for coolant), but the bigger laser like that one which I presented would simply evaporate the armor and the coolant below the armor in miliseconds.
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Post by bigbombr on Jan 3, 2017 18:26:06 GMT
Depends on how much juice you're getting hit with. The main danger of lasers is not that they project large amounts of energy, it's that they focus this on a small area. An active cooling system would allow you spread out that heat and radiate more of it away (hopefully keeping the temperature low enough to keep your armour from ablating). I think that problem is not with heat sinks (it's still only 340 MW of power, you can use radiators to remove that heat), it's with transmission of heat. For smaller lasers that might work, (although you would probably need absurdly big pumps for coolant), but the bigger laser like that one which I presented would simply evaporate the armor and the coolant below the armor in miliseconds. So you'd need a thermal conductor, make it thin and have a continuous flow of coolant (hydrogen, water,ethane, ...) underneath.
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Post by n2maniac on Jan 3, 2017 18:27:00 GMT
You'd need massive heat sinks for that. Depends on how much juice you're getting hit with. The main danger of lasers is not that they project large amounts of energy, it's that they focus this on a small area. An active cooling system would allow you spread out that heat and radiate more of it away (hopefully keeping the temperature low enough to keep your armour from ablating). The reactors people make that hit the limit of the W-Ta thermocouples' thermal stress and maximized possible heat flux across their 1mm thickness handle a little over 100 MW/m2. If the laser power is significantly above that (staring at the 2 PW/m2 number), I would be skeptical of heat dissipation being viable.
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Post by lawson on Jan 4, 2017 9:04:17 GMT
Depends on how much juice you're getting hit with. The main danger of lasers is not that they project large amounts of energy, it's that they focus this on a small area. An active cooling system would allow you spread out that heat and radiate more of it away (hopefully keeping the temperature low enough to keep your armour from ablating). The reactors people make that hit the limit of the W-Ta thermocouples' thermal stress and maximized possible heat flux across their 1mm thickness handle a little over 100 MW/m2. If the laser power is significantly above that (staring at the 2 PW/m2 number), I would be skeptical of heat dissipation being viable. Yup, and the best way I can think of to get around the small spot size of most lasers is to leverage the high damage threshold of transparent materials to spread out the spot. (a rough diamond layer with the appropriate surface coating should be ideal) Expand the spot to >2 meters in diameter, and an actively cooled mirrored wall becomes viable. Note: this armor fails as soon as the laser gets focused enough to shatter the transparent diffuser layer.
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Post by newageofpower on Jan 4, 2017 10:00:33 GMT
The reactors people make that hit the limit of the W-Ta thermocouples' thermal stress and maximized possible heat flux across their 1mm thickness handle a little over 100 MW/m2. If the laser power is significantly above that (staring at the 2 PW/m2 number), I would be skeptical of heat dissipation being viable. Yup, and the best way I can think of to get around the small spot size of most lasers is to leverage the high damage threshold of transparent materials to spread out the spot. (a rough diamond layer with the appropriate surface coating should be ideal) Expand the spot to >2 meters in diameter, and an actively cooled mirrored wall becomes viable. Note: this armor fails as soon as the laser gets focused enough to shatter the transparent diffuser layer. As the transparent layer gets more efficient at diffusing laser energy, it also absorbs more laser energy. This imposes a pretty hard cap on your active cooling technique, and we haven't even gotten into high-efficiency FEL based lasers. Still, a fascinating workaround.
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Post by bigbombr on Jan 4, 2017 10:20:02 GMT
Yup, and the best way I can think of to get around the small spot size of most lasers is to leverage the high damage threshold of transparent materials to spread out the spot. (a rough diamond layer with the appropriate surface coating should be ideal) Expand the spot to >2 meters in diameter, and an actively cooled mirrored wall becomes viable. Note: this armor fails as soon as the laser gets focused enough to shatter the transparent diffuser layer. As the transparent layer gets more efficient at diffusing laser energy, it also absorbs more laser energy. This imposes a pretty hard cap on your active cooling technique, and we haven't even gotten into high-efficiency FEL based lasers. Still, a fascinating workaround. What if you would use a transparant outer layer (quartz or a thin layer of diamond) with right underneath, a thicker layer of continuously flowing coolant? The coolant,instead of the outer layer, would absorb the laser. Because you can use something like water (high heat capacity, high transparency so that the heating by the laser gets spread through the thickness of the layer) that flows continuously might be able to take considerable punishment (from lasers, against anything else, well, you're shooting at essentially a fishbowl).
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Post by newageofpower on Jan 4, 2017 10:33:31 GMT
What if you would use a transparant outer layer (quartz or a thin layer of diamond) with right underneath, a thicker layer of continuously flowing coolant? The coolant,instead of the outer layer, would absorb the laser. Because you can use something like water (high heat capacity, high transparency so that the heating by the laser gets spread through the thickness of the layer) that flows continuously might be able to take considerable punishment (from lasers, against anything else, well, you're shooting at essentially a fishbowl). Diamond-armored fishbowls are fairly resistant to sand ;p
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Post by coaxjack on Jan 5, 2017 16:36:48 GMT
You could also include some sort of coagulant compound in the coolant so if the outer layer were to be punctured by something, the entire supply of coolant wouldn't escape. Something that would remain liquid under pressure while in the system, but harden when exposed to vacuum.
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Post by Enderminion on Jan 10, 2017 18:12:26 GMT
You could also include some sort of coagulant compound in the coolant so if the outer layer were to be punctured by something, the entire supply of coolant wouldn't escape. Something that would remain liquid under pressure while in the system, but harden when exposed to vacuum. Simpler then that have a section around the breach seal shut
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Post by coaxjack on Jan 10, 2017 18:23:01 GMT
That would imply hundreds of bulkheads to isolate different parts of the system.
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Post by caiaphas on Jan 10, 2017 19:33:37 GMT
That would imply hundreds of bulkheads to isolate different parts of the system. Plus mechanical doodads to move them around (actuators? think they're actuators).
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Post by coaxjack on Jan 10, 2017 21:41:57 GMT
That would imply hundreds of bulkheads to isolate different parts of the system. Plus mechanical doodads to move them around (actuators? think they're actuators). Exactly, the fluid is supposed to be in there anyway, so instead of mechanically isolating the breach, engineer the fluid so it crystallizes quickly and stiffly when flowing rapidly into vacuum. Even regular water would work with a thickening agent, as regular water would just turn into a tiny RCS jet with a throat diameter the size of the bullet hole, that has snow for exhaust.
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