Post by pokington on Oct 15, 2016 19:40:33 GMT
Now that RP-1 is a valid and usable propellant, it's painfully obvious that it is not correct in the materials files.
In Combustables.txt RP-1 is listed as CH2, which, while roughly correct for the ratio between carbons and hydrogens, does not accurately reflect the much larger molecular mass of RP-1. RP-1 is (simplistically) dodecane, or C12H26.
In Combustables.txt, RP-1 should be changed to:
And the corresponding entries in ChemicalReactions.txt should be changed as well:
This results in an chemical LOX/RP-1 rocket that maxes out at about 350s Isp, and a higher thrust/lower Isp version of the decane NTR.
This is definitely a simplistic view of RP-1, but as a first pass treating it like dodecane gets pretty solid results and changes it from a completely broken and useless propellant to an even denser, lower isp version of decane.
tl;dr qswitched -- in addition to checking the other figures for RP-1, please go in and take a look at the RP-1 chemical composition and reactions. I think it has some great utility for high-thrust bipropellant engines and NTRs.
In Combustables.txt RP-1 is listed as CH2, which, while roughly correct for the ratio between carbons and hydrogens, does not accurately reflect the much larger molecular mass of RP-1. RP-1 is (simplistically) dodecane, or C12H26.
In Combustables.txt, RP-1 should be changed to:
Material RP-1
Elements C H
ElementCount 12 26
Density_kg__m3 769
EnthalpyOfFormation_kJ__mol -462.2
MeltingPoint_K 283.1
BoilingPoint_K 560
SpecificHeat_J__kg_K 1880
ThermalConductivity_W__m_K .110
BulkModulus_GPa 1.034
Viscosity_Pa_s 1.64e-2
Dissociation
Products Monatomic Carbon Monatomic Hydrogen
ProductCounts 12 26
Elements C H
ElementCount 12 26
Density_kg__m3 769
EnthalpyOfFormation_kJ__mol -462.2
MeltingPoint_K 283.1
BoilingPoint_K 560
SpecificHeat_J__kg_K 1880
ThermalConductivity_W__m_K .110
BulkModulus_GPa 1.034
Viscosity_Pa_s 1.64e-2
Dissociation
Products Monatomic Carbon Monatomic Hydrogen
ProductCounts 12 26
And the corresponding entries in ChemicalReactions.txt should be changed as well:
ChemicalReaction LOX RP-1
Reactants Oxygen RP-1
ReactantCounts 37 2
Products Carbon Dioxide Water
ProductCounts 24 26
ActivationEnergy_kJ__mol 12.0
AutoignitionTemperature_K 673
CharacteristicLength_m 1.143
Reactants Oxygen RP-1
ReactantCounts 37 2
Products Carbon Dioxide Water
ProductCounts 24 26
ActivationEnergy_kJ__mol 12.0
AutoignitionTemperature_K 673
CharacteristicLength_m 1.143
ChemicalReaction Nitrous Oxide RP-1
Reactants Nitrous Oxide RP-1
ReactantCounts 37 1
Products Nitrogen Water Carbon Dioxide
ProductCounts 37 13 12
ActivationEnergy_kJ__mol 250
AutoignitionTemperature_K 850
CharacteristicLength_m .9
Reactants Nitrous Oxide RP-1
ReactantCounts 37 1
Products Nitrogen Water Carbon Dioxide
ProductCounts 37 13 12
ActivationEnergy_kJ__mol 250
AutoignitionTemperature_K 850
CharacteristicLength_m .9
This results in an chemical LOX/RP-1 rocket that maxes out at about 350s Isp, and a higher thrust/lower Isp version of the decane NTR.
This is definitely a simplistic view of RP-1, but as a first pass treating it like dodecane gets pretty solid results and changes it from a completely broken and useless propellant to an even denser, lower isp version of decane.
tl;dr qswitched -- in addition to checking the other figures for RP-1, please go in and take a look at the RP-1 chemical composition and reactions. I think it has some great utility for high-thrust bipropellant engines and NTRs.