The 70% is just the Carnot efficiency: (1-T1/T0) where T0 is the combustion chamber Kelvin temperature and T1 is the exhaust's.
That has to be discounted by the efficiency of the EHD conversion -- which is the big question here. On Tue, Apr 9, 2013 at 12:58 PM, David Lautenschlager < [email protected]> wrote: > H2O gas is a much stronger green house gas than CO2(though shorter lived > in the atmosphere). Fortunately most of it is condensed in this case, so > even if you class green house gasses as pollutants, the exhaust is closer > to 5% than 60% pollutants.(of course, classing respiration gasses as > pollutants is rather irrational). > > Is the 70% efficiency fuel to electricity? That seems high. > > Dave > > ------------------------------ > *From:* James Bowery <[email protected]> > *To:* vortex-l <[email protected]>; [email protected] > *Sent:* Tuesday, April 9, 2013 12:17 AM > > *Subject:* [AR] Rocket Driven Lord Kelvin's Thunderstorm > > Given the below results from the rocket propellant simulator: > > http://rocketworkbench.sourceforge.net/equil.phtml > > We have an air+methane+water fuel mixture rocket expelling droplets of > liquid water travelling at 1305m/s with a Carnot efficiency of about 70%. > > If you take two such rocket engines and put them in place of the water > droplets of a Lord Kelvin's Thunderstorm, you have would would appear to be > an electrohydrodynamic DC power station with the following rather > characteristics: > > * very high voltage > * high power to weight > * reasonably efficient > * burns a fuel that is cheap for at least the next several years > * NOx in sub-ppm as the only pollutant other than CO2 (which is a green > house gas) > * might even be used as water treatment. > * the only moving parts are the compressors > * very little touble with cooling capacity given the H2O mass flow rate > * with additional downstream equipment might be tuned to treat water as a > side job > > Sorry for the cross-post to vortex-l as well as arocket but this is up > Beatty's (vortex-l's) alley and certainly involves small scale liquid > rocketry. > Results > > Propellant composition > Code Name mol Mass (g) Composition > 976 WATER 512.0000 9223.8235 2H 1O > 578 METHANE 55.0000 882.3353 1C 4H > 15 AIR (DRY AT SEA LEVEL) 1.0000 15479.2332 835N 224O 5AR > Density : 2.261 g/cm^3 > 5 different elements > H O C N AR > Total mass: 25585.392031 g > Enthalpy : -5907.12 kJ/kg > > 149 possible gazeous species > 3 possible condensed species > > CHAMBER THROAT EXIT > Pressure (atm) : 100.000 54.524 1.000 > Temperature (K) : 851.960 741.912 273.659 > H (kJ/kg) : -5907.117 -6079.928 -6758.571 > U (kJ/kg) : -6212.081 -6345.499 -6856.528 > G (kJ/kg) : -13075.582 -12322.436 -9061.163 > S (kJ/(kg)(K) : 8.414 8.414 8.414 > M (g/mol) : 23.228 23.228 23.228 > (dLnV/dLnP)t : -1.00000 -1.00000 -1.00000 > (dLnV/dLnT)p : 1.00000 1.00000 1.00000 > Cp (kJ/(kg)(K)) : 1.59515 1.54548 1.37312 > Cv (kJ/(kg)(K)) : 1.23719 1.18752 1.01517 > Cp/Cv : 1.28933 1.30143 1.35261 > Gamma : 1.28933 1.30143 1.35261 > Vson (m/s) : 627.05454 587.89672 355.38692 > > Ae/At : 1.00000 9.06046 > A/dotm (m/s/atm) : 8.28502 75.06605 > C* (m/s) : 828.50159 828.50159 > Cf : 0.70959 1.57508 > Ivac (m/s) : 1039.62801 1380.02098 > Isp (m/s) : 587.89672 1304.95492 > Isp/g (s) : 59.94878 133.06837 > > Molar fractions > > Ar 4.5393e-03 4.5393e-03 4.5393e-03 > CO2 4.9932e-02 4.9932e-02 4.9932e-02 > H2O 5.6468e-01 5.6468e-01 5.6468e-01 > NO 2.9860e-07 2.9860e-07 2.9860e-07 > NO2 5.0825e-08 5.0825e-08 5.0825e-08 > N2 3.7903e-01 3.7903e-01 3.7903e-01 > O2 1.8155e-03 1.8155e-03 1.8155e-03 > > > _______________________________________________ > [email protected] > http://exrocketry.net/mailman/listinfo/arocket > > > > _______________________________________________ > [email protected] > http://exrocketry.net/mailman/listinfo/arocket > >
