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