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Post by RiftandRend on May 26, 2017 6:01:51 GMT
One of the most limiting factors in reactor design is thermocouples cracking from thermal expansion. By using diamond or other high strength+melting point materials (looking at you graphene) as reinforcement this could be reduced significantly. In testing with a mockup material I was able to cut reactor cost by 50%.
Basic concept material for testing.
Yield and UTS as well as thermal properties are an average between Tungsten and Diamond.
Material Diamond Reinforced Tungsten Elements W C ElementCount 1 1 Density_kg__m3 11385 YieldStrength_MPa 1270 UltimateTensileStrength_MPa 2155 YoungsModulus_GPa 410 ShearModulus_GPa 161 SpecificHeat_J__kg_K 326.5 MeltingPoint_K 3643 BoilingPoint_K 5282 ThermalConductivity_W__m_K 1136 ThermalExpansion__K 0.0000027 Resistivity_Ohm_m 5.28e-8 RelativePermeability 7.8 ThermoelectricSensitivity_V__K 2.5e-6 LasingDamageThreshold_TW__m2 .065 RefractiveIndex Tungsten RoughnessCoefficient 0.1
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Post by AdmiralObvious on May 26, 2017 6:08:55 GMT
I don't understand, wouldn't the material crack regardless of the reinforcing medium?
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Post by RiftandRend on May 26, 2017 6:19:10 GMT
I don't understand, wouldn't the material crack regardless of the reinforcing medium? It can still conduct and function even if its shards, the reinforcements keep in it place.
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Post by ash19256 on May 26, 2017 9:28:47 GMT
Question then becomes a matter of whether or not we could get a version of this for pyrolitic carbon. If we could then my reactor designs could get much cheaper, due to being able to run the thermocouple under greater stress, which in turn will allow for even greater reactor efficiency.
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Post by RiftandRend on May 26, 2017 19:06:24 GMT
Question then becomes a matter of whether or not we could get a version of this for pyrolytic carbon. If we could then my reactor designs could get much cheaper, due to being able to run the thermocouple under greater stress, which in turn will allow for even greater reactor efficiency. When used with materials with negative thermoelectric coefficients Diamond's high coefficient may interfere.
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Post by Pttg on May 26, 2017 19:21:32 GMT
Also, why make monolithic thermocouples? Hundreds of cm-sized thermocouples in a set of hexes, in a flexible manifold, could change shape as needed without cracking the overall structure.
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Post by ash19256 on May 26, 2017 20:28:46 GMT
Question then becomes a matter of whether or not we could get a version of this for pyrolitic carbon. If we could then my reactor designs could get much cheaper, due to being able to run the thermocouple under greater stress, which in turn will allow for even greater reactor efficiency. When used with materials with negative thermoelectric coefficients Diamond's high coefficient may interfere. The question then becomes one of whether or not either Grapene or 3D-Graphene reinforcment would cause problems with pyrolitic carbon.
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Post by RiftandRend on May 26, 2017 21:55:38 GMT
When used with materials with negative thermoelectric coefficients Diamond's high coefficient may interfere. The question then becomes one of whether or not either Graphene or 3D-Graphene reinforcement would cause problems with pyrolytic carbon. IIRC graphene had a very high thermoelectric coefficient, and I suspect 3D-Graphene may be similar.
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Post by morrigi on Jun 16, 2017 10:15:26 GMT
Also, why make monolithic thermocouples? Hundreds of cm-sized thermocouples in a set of hexes, in a flexible manifold, could change shape as needed without cracking the overall structure. Sounds expensive. Also almost certainly worth it.
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Post by n2maniac on Jun 17, 2017 3:31:58 GMT
Just anneal the material in a pre-stressed state or run the reactor at a temperature that will anneal it automatically. Which, near the melting point of the materials in question, is probably happening anyways. The trouble is this type of material interaction is not modeled.
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Post by captinjoehenry on Jun 17, 2017 21:58:34 GMT
Is there any material we could use to reinforce a negative thermoelectric sensitive material? I mean Gadolinium has a -175uV/K and Graphene only has a 90uV/K so that should work right? Also reinforcing selenium would be a brilliant idea as it has 895 uV/K but is unusable due to its melting point.
As it is a pure Selenium Gadolinium thermocouple boosts my reactor efficiency to 91% so if those materials could be reinforced with graphene it would be really great.
My shot at making matrices of Selenium and Gadolinium. So same physical properties as Graphene with the average thermoelectric value divided by 2 to represent the more graphene than metal.
Material Graphene Gadolinium Matrix Elements C Gd ElementCount 3 1 Density_kg__m3 2300 IsNanostructured true YieldStrength_MPa 130000 UltimateTensileStrength_MPa 130000 YoungsModulus_GPa 800 ShearModulus_GPa 280 BulkModulus_GPa 8 MeltingPoint_K 4500 SpecificHeat_J__kg_K 51930 ThermalConductivity_W__m_K 2500 ThermalExpansion__K -8e-6 ThermoelectricSensitivity_V__K -2.1e-5 Resistivity_Ohm_m 3.3e-6 RefractiveIndex Graphene RoughnessCoefficient 0.9
Material Graphene Selenium Matrix Elements C Se ElementCount 3 1 Density_kg__m3 2300 IsNanostructured true YieldStrength_MPa 130000 UltimateTensileStrength_MPa 130000 YoungsModulus_GPa 800 ShearModulus_GPa 280 BulkModulus_GPa 8 MeltingPoint_K 4500 SpecificHeat_J__kg_K 51930 ThermalConductivity_W__m_K 2500 ThermalExpansion__K -8e-6 ThermoelectricSensitivity_V__K 246e-5 Resistivity_Ohm_m 3.3e-6 RefractiveIndex Graphene RoughnessCoefficient 0.9
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Post by Rocket Witch on Jun 17, 2017 23:17:38 GMT
How is the reinforcement done? I doubt one could completely envelope the thermocouple in graphene and expect it to have the original thermoelectric sensitivity.
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Post by bigbombr on Jun 18, 2017 6:43:34 GMT
How is the reinforcement done? I doubt one could completely envelope the thermocouple in graphene and expect it to have the original thermoelectric sensitivity. And graphene also often behaves odd in composites/when doped with other materials.
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Post by ash19256 on Jun 18, 2017 7:29:46 GMT
How is the reinforcement done? I doubt one could completely envelope the thermocouple in graphene and expect it to have the original thermoelectric sensitivity. And graphene also often behaves odd in composites/when doped with other materials. Not that this really helps much, as I'm unable to get the efficiency up above approximately 49%, and even then the result is that the reactor's cost balloons to almost 100 times it's original cost, because these composites/doped materials cost more than 5 kc per kilogram.
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Post by n2maniac on Jun 19, 2017 4:48:38 GMT
Is there any material we could use to reinforce a negative thermoelectric sensitive material? I mean Gadolinium has a -175uV/K and Graphene only has a 90uV/K so that should work right? Also reinforcing selenium would be a brilliant idea as it has 895 uV/K but is unusable due to its melting point. As it is a pure Selenium Gadolinium thermocouple boosts my reactor efficiency to 91% so if those materials could be reinforced with graphene it would be really great. My shot at making matrices of Selenium and Gadolinium. So same physical properties as Graphene with the average thermoelectric value divided by 2 to represent the more graphene than metal. [...] You won't beat Carnot efficiency, and the ingame materials are already really damn close. Power per area is based heavily on the square of the voltage dfference versus the material's electrical conductivity, and that may get affected here. I would be very surprised if this made much difference (other than through extending the delta T or changing reactor compactness).
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