New Propellants¶
New propellants can be added and existing propellants modified.
Create a python string variable that contains the new card. It can be multiline such as:
card_str = """
oxid N2O4(L) N 2 O 4 wt%=96.5
h,cal=-4676.0 t(k)=298.15
oxid SiO2 Si 1.0 O 2.0 wt%=3.5
h,cal=-216000.0 t(k)=298.15 rho=1.48
"""
Add the new propellant card to RocketCEA and give it a name. It can be added as oxidizer, fuel or propellant.:
add_new_oxidizer( 'GelN2O4', card_str )
add_new_fuel( 'MMH_AL', card_str )
add_new_propellant( 'MyProp', card_str )
New Ox and Fuel¶
The example below defines some gel propellants, adding SiO2 to the oxidizer and Al to the fuel.
from rocketcea.cea_obj import CEA_Obj, add_new_fuel, add_new_oxidizer, add_new_propellant
card_str = """
oxid N2O4(L) N 2 O 4 wt%=96.5
h,cal=-4676.0 t(k)=298.15
oxid SiO2 Si 1.0 O 2.0 wt%=3.5
h,cal=-216000.0 t(k)=298.15 rho=1.48
"""
add_new_oxidizer( 'GelN2O4', card_str )
# ==========
card_str = """
fuel CH6N2(L) C 1.0 H 6.0 N 2.0 wt%=60.00
h,cal=12900.0 t(k)=298.15 rho=.874
fuel AL AL 1.0 wt%=40.00
h,cal=0.0 t(k)=298.15 rho=0.1
"""
add_new_fuel( 'MMH_AL', card_str )
C = CEA_Obj(oxName="GelN2O4", fuelName="MMH_AL")
s = C.get_full_cea_output( Pc=1850.0, MR=0.7, eps=40.0, short_output=1)
print( s )
Outputs:
*******************************************************************************
NASA-GLENN CHEMICAL EQUILIBRIUM PROGRAM CEA, OCTOBER 18, 2002
BY BONNIE MCBRIDE AND SANFORD GORDON
REFS: NASA RP-1311, PART I, 1994 AND NASA RP-1311, PART II, 1996
*******************************************************************************
reac
fuel CH6N2(L) C 1.0 H 6.0 N 2.0 wt%=60.00
h,cal=12900.0 t(k)=298.15 rho=.874
fuel AL AL 1.0 wt%=40.00
h,cal=0.0 t(k)=298.15 rho=0.1
oxid N2O4(L) N 2 O 4 wt%=96.5
h,cal=-4676.0 t(k)=298.15
oxid SiO2 Si 1.0 O 2.0 wt%=3.5
h,cal=-216000.0 t(k)=298.15 rho=1.48
prob case=GelN2O4_/_MMH_AL
rocket equilibrium p,psia=1850.000000, supar=40.000000,
o/f=0.700000
outp calories short
end
THEORETICAL ROCKET PERFORMANCE ASSUMING EQUILIBRIUM
COMPOSITION DURING EXPANSION FROM INFINITE AREA COMBUSTOR
Pinj = 1850.0 PSIA
CASE = GelN2O4_/_MMH_A
REACTANT WT FRACTION ENERGY TEMP
(SEE NOTE) CAL/MOL K
FUEL CH6N2(L) 0.6000000 12900.000 298.150
FUEL AL 0.4000000 0.000 298.150
OXIDANT N2O4(L) 0.9650000 -4676.000 298.150
OXIDANT SiO2 0.0350000 -216000.000 298.150
REACTANT DENSITY= 42.2857 G/CC
O/F= 0.70000 %FUEL= 58.823529 R,EQ.RATIO= 2.921279 PHI,EQ.RATIO= 2.974634
CHAMBER THROAT EXIT
Pinf/P 1.0000 1.7251 363.79
P, ATM 125.88 72.973 0.34604
T, K 3082.43 2905.55 1698.41
RHO, G/CC 1.1177-2 6.9501-3 6.0631-5
H, CAL/G 26.820 -116.52 -1150.32
U, CAL/G -245.95 -370.79 -1288.54
G, CAL/G -7686.58 -7387.30 -5400.38
S, CAL/(G)(K) 2.5024 2.5024 2.5024
M, (1/n) 22.457 22.708 24.419
MW, MOL WT 21.109 21.154 21.314
(dLV/dLP)t -1.01858 -1.08537 -1.07583
(dLV/dLT)p 1.2354 2.3383 2.8119
Cp, CAL/(G)(K) 0.8362 2.4115 4.0182
GAMMAs 1.1668 1.1275 1.0921
SON VEL,M/SEC 1153.9 1095.2 794.7
MACH NUMBER 0.000 1.000 3.949
PERFORMANCE PARAMETERS
Ae/At 1.0000 40.000
CSTAR, FT/SEC 5497.8 5497.8
CF 0.6536 1.8729
Ivac,LB-SEC/LB 210.7 338.8
Isp, LB-SEC/LB 111.7 320.0
MOLE FRACTIONS
*AL 0.00600 0.00518 0.00000
ALH 0.00437 0.00353 0.00000
ALH2 0.00006 0.00003 0.00000
ALH3 0.00002 0.00001 0.00000
ALN 0.00001 0.00001 0.00000
*ALO 0.00007 0.00003 0.00000
ALOH 0.00979 0.00662 0.00000
AL(OH)2 0.00001 0.00000 0.00000
AL2 0.00005 0.00003 0.00000
AL2O 0.02172 0.01895 0.00000
AL2O2 0.00006 0.00003 0.00000
CH3 0.00004 0.00004 0.00000
CH4 0.00011 0.00012 0.00011
*CN 0.00001 0.00001 0.00000
*CO 0.15623 0.15626 0.14630
*CO2 0.00007 0.00004 0.00000
C2H2,acetylene 0.00009 0.00012 0.00004
*H 0.01187 0.00904 0.00016
HCN 0.00423 0.00459 0.00142
HCO 0.00002 0.00001 0.00000
HNC 0.00079 0.00074 0.00004
*H2 0.46728 0.47240 0.48876
H2O 0.00153 0.00083 0.00001
NH2 0.00002 0.00001 0.00000
NH3 0.00014 0.00009 0.00000
*N2 0.25026 0.24773 0.23571
*OH 0.00001 0.00001 0.00000
*Si 0.00003 0.00003 0.00000
SiH 0.00004 0.00004 0.00000
SiH2 0.00001 0.00001 0.00000
SiO 0.00497 0.00499 0.00028
ALN(cr) 0.00000 0.00000 0.03294
ALN(L) 0.00000 0.00589 0.00000
AL2O3(a) 0.00000 0.00000 0.07646
AL2O3(L) 0.06004 0.06257 0.00000
C(gr) 0.00000 0.00000 0.01534
Si2N2O(cr) 0.00000 0.00000 0.00242
* THERMODYNAMIC PROPERTIES FITTED TO 20000.K
NOTE. WEIGHT FRACTION OF FUEL IN TOTAL FUELS AND OF OXIDANT IN TOTAL OXIDANTS
New Monoprop¶
from rocketcea.cea_obj import CEA_Obj, add_new_fuel, add_new_oxidizer, add_new_propellant
# ==========
card_str = """
name H2O2(L) H 2 O 2 wt%=100.00
h,cal=-44880.0 t(k)=298.15 rho.g/cc=1.407
"""
add_new_propellant( 'MyProp', card_str )
C = CEA_Obj(propName="MyProp")
s = C.get_full_cea_output( Pc=250.0, eps=40.0, short_output=1)
print( s )
Outputs:
*******************************************************************************
NASA-GLENN CHEMICAL EQUILIBRIUM PROGRAM CEA, OCTOBER 18, 2002
BY BONNIE MCBRIDE AND SANFORD GORDON
REFS: NASA RP-1311, PART I, 1994 AND NASA RP-1311, PART II, 1996
*******************************************************************************
reac
name H2O2(L) H 2 O 2 wt%=100.00
h,cal=-44880.0 t(k)=298.15 rho.g/cc=1.407
prob case= MyProp
rocket equilibrium p,psia=250.000000, supar=40.000000,
outp calories short
end
THEORETICAL ROCKET PERFORMANCE ASSUMING EQUILIBRIUM
COMPOSITION DURING EXPANSION FROM INFINITE AREA COMBUSTOR
Pinj = 250.0 PSIA
CASE = MyProp
REACTANT WT FRACTION ENERGY TEMP
(SEE NOTE) CAL/MOL K
NAME H2O2(L) 1.0000000 -44880.000 298.150
REACTANT DENSITY= 1.4070 G/CC
O/F= 0.00000 %FUEL= 0.000000 R,EQ.RATIO= 0.500000 PHI,EQ.RATIO= 0.000000
CHAMBER THROAT EXIT
Pinf/P 1.0000 1.8080 718.01
P, ATM 17.011 9.4092 0.02369
T, K 1274.61 1130.86 287.09
RHO, G/CC 3.6882-3 2.2993-3 2.3038-5
H, CAL/G -1319.43 -1381.79 -1707.68
U, CAL/G -1431.13 -1480.90 -1732.58
G, CAL/G -4379.64 -4096.87 -2396.94
S, CAL/(G)(K) 2.4009 2.4009 2.4009
M, (1/n) 22.676 22.676 22.907
MW, MOL WT 22.676 22.676 22.676
(dLV/dLP)t -1.00000 -1.00000 -2.96976
(dLV/dLT)p 1.0001 1.0000 37.6942
Cp, CAL/(G)(K) 0.4410 0.4265 59.6427
GAMMAs 1.2480 1.2586 1.1073
SON VEL,M/SEC 763.7 722.4 339.7
MACH NUMBER 0.000 1.000 5.306
PERFORMANCE PARAMETERS
Ae/At 1.0000 40.000
CSTAR, FT/SEC 3404.6 3404.6
CF 0.6961 1.7369
Ivac,LB-SEC/LB 132.2 189.7
Isp, LB-SEC/LB 73.7 183.8
MOLE FRACTIONS
H2O 0.66666 0.66667 0.65659
*OH 0.00001 0.00000 0.00000
*O2 0.33333 0.33333 0.33333
H2O(L) 0.00000 0.00000 0.01008
* THERMODYNAMIC PROPERTIES FITTED TO 20000.K
NOTE. WEIGHT FRACTION OF FUEL IN TOTAL FUELS AND OF OXIDANT IN TOTAL OXIDANTS