def __init__(self):
self.datapathname = './.lookup.npy'
self.configpathname = './.lookupconfig.json'
self.data = None
self.config = None
self.__loaded = False
# This str provides molecular structure, wt% of fuel, heat of formation, and density information to underlying CEA code
fuel_str = """
fuel ABS(S) C 3.85 H 4.85 N 0.43 wt%=100.0
h,kJ=62.63 t(k)=298.15 rho,kg=1224
"""
add_new_fuel('ABS', fuel_str)
self.cea = CEA_Obj(oxName='N2O',
fuelName='ABS',
cstar_units='m/s',
pressure_units='Pa',
temperature_units='K',
sonic_velocity_units='m/s',
enthalpy_units='J/kg',
density_units='kg/m^3',
specific_heat_units='J/kg-K',
viscosity_units='poise',
thermal_cond_units='W/cm-degC',
make_debug_prints=True)
def test_new_propellants(self):
card_str = """
oxid N2O4(L) N 2 O 4 wt%=96.5
h,cal=-4676.0 t(k)=298.15
oxid SIO2 SI 1 O 2 wt%=3,5
h,cal=-216000.0 t(k)=298.15 rho.g/cc=1.48
"""
add_new_oxidizer('GelN2O4', card_str)
# ==========
card_str = """
fuel CH6N2(L) C 1 H 6 N 2 wt%=60.00
h,cal=12900.0 t(k)=298.15 rho=.874
fuel AL 1 wt%=40.00
h,cal=0.0 t(k)=298.15 rho=.1
"""
add_new_fuel('MMH_AL', card_str)
C = CEA_Obj(oxName="GelN2O4", fuelName="MMH_AL", fac_CR=None)
IspODE = C.get_Isp(Pc=1850.0, MR=0.7, eps=40.0)
self.assertAlmostEqual(IspODE, 380.83236183365057, places=3)
# ==========
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", fac_CR=None)
IspODE = C.get_Isp(Pc=1850.0, eps=40.0)
self.assertAlmostEqual(IspODE, 189.9709005711723, places=3)
def addCustomSpecies(self):
# Add custom species to CEA
card_str = """
fuel ABS C 3.85 H 4.85 N 0.43 wt%=100.00
h,cal=14990 t(k)=298.15 rho=0.975
"""
add_new_fuel('ABS', card_str)
card_str = """
fuel Acrylic C 5 H 8 O 2 wt%=100.00
h,cal=91396 t(k)=298.15 rho=1.18
"""
add_new_fuel('Acrylic', card_str)
def define_propellants():
""" define the string that characterizes the fuel """
# Introduce the fuel definition
fuel_card = "fuel=Air wt=0.01 t(k)=298 " \
"fuel=ABS wt=99.9 t(k)=298 " \
"h,kj/mol=62.63 C 3.85 H 4.85 N 0.43"
# Introduce the oxidizer definition
oxidizer_card = "oxid=H2O2(L) wt=87.5 t(k)=298 " \
"oxid=H2O(L) wt=12.5 t(k)=298"
# Add the new fuel and oxidizer
cea_obj.add_new_fuel("3DPrinted_ABS", fuel_card)
cea_obj.add_new_oxidizer("GriffonOxydizer_H2O2", oxidizer_card)
def cea_card(self):
# Create cea card and rocketcea fuel/oxidizer
self.card += self.name + " "
self.card += self.formula + " "
self.card += "wt%=100" + " "
# self.card += "h,cal={:.3f}".format(self.storage_enthalpy/4.184) + " "
self.card += "t(k)={:.3f}".format(self.storage_temperature) + " "
self.card += ("rho={:.3f}".format(self.storage_density / 1000) + " "
) # convert density to g/cc
if self.fluid_type == "oxidizer":
self.card = "oxid " + self.card
add_new_oxidizer(self.name, self.card)
elif self.fluid_type == "fuel":
self.card = "fuel " + self.card
add_new_fuel(self.name, self.card)
return self.card
def define_fuel(fuel_table):
"""
define_fuel constructs the propellant card (str) that's associated to
the fuel.
:param fuel_table: dict containing the fuel table as specified in the data-layer
:return: Nothing
"""
# Initialize the fuel card
card = []
# Loop through the fuels list and generate the string associated to it
for fuel_type in fuel_table['components']:
# Define the basic fields
card.append("fuel={name}".format(name=fuel_type['fuel']))
card.append("wt={wt}".format(wt=fuel_type['wt']))
card.append("t{units}={value}".format(
units=fuel_type['t']['units'],
value=fuel_type['t']['value']))
# Check if more complex fields are present for the fuel
if "h" in fuel_type:
card.append("h,{units}={value}".format(
units=fuel_type['h']['units'],
value=fuel_type['h']['value']))
if "composition" in fuel_type:
card.append(" ".join(
("{name} {value}".format(name=key, value=val)
for key, val in fuel_type['composition'].items())))
# Join the card
card = " ".join(card)
# Add the fuel to the cea_obj
cea_obj.add_new_fuel(fuel_table['name'], card)
## inputs
P = range(150, 500, 20) # range of chamber pressures to test
## add PMMA definition
card_str = '''
fuel PMMA C 5 H 8 O 2
h,kj=-430.5 t(k)=299.82
''' # Greg Zilliac's recommendation for modeling PMMA
# HTPB Definition (not used right now)
card_str2 = '''
fuel HTPB C 7.3165 H 10.3360 O 0.1063 wt%=100.00
h,cal= 1200.0 t(k)=298.15 rho=0.9220
'''
add_new_fuel('PMMA', card_str) # rocketCEA function to add PMMA to inputs
def rocket_vars(fu, ox, pcham):
C = CEA_Obj(
oxName=ox, fuelName=fu, isp_units='sec',
cstar_units='m/s') # define CEA object to operate on for rocketCEA
OFratio = np.linspace(0.1, 5., 50, endpoint=True) # OF ratio by mass
ISP = np.zeros(OFratio.shape) # isp
Cstar = np.zeros(OFratio.shape) # cstar efficiency
PCPE = np.zeros(OFratio.shape) # p_chamber / p_exit
supAR = 1 # supersonic area ratio (1 = converging nozzle only)
for i in range(50):
ISP[i] = C.get_Isp(pcham, MR=OFratio[i], eps=supAR) # ISP vacuum
Cstar[i] = C.get_Cstar(pcham, MR=OFratio[i]) # Cstar efficiency
PCPE[i] = C.get_Throat_PcOvPe(
def getPerformanceParameters(self, combustionPressure, ambientPressure,
oxidizerTemperature, expansionRatio,
mixtureRatio):
CpAve = CP.PropsSI('CP0MOLAR', 'T', oxidizerTemperature, 'P',
combustionPressure, "N2O")
MolWt = CP.PropsSI('M', 'T', oxidizerTemperature, 'P',
combustionPressure, "N2O") * 1e3
HMOLAR = CP.PropsSI('HMOLAR', 'T', oxidizerTemperature, 'P',
combustionPressure, "N2O") / 1e3
RHO = CP.PropsSI('D', 'T', oxidizerTemperature, 'P',
combustionPressure, "N2O") * 1e3 / (1e2 * 1e2 * 1e2)
# print(HMOLAR, RHO)
card_str = """
oxid=NITROUS wt=1.0 t,K={:.4f} h,kj/mol={:.4f} rho,g/cc={:.4f} N 2 O 1
""".format(oxidizerTemperature, HMOLAR, RHO)
add_new_oxidizer('NITROUS_COOLPROP',
card_str.format(oxidizerTemperature))
fuelTemperature = 293
card_str = """
fuel=C(gr) wt=0.02 t,K={:.4f}
fuel=SASOL907 wt=0.98 t,K={:.4f} h,kj/mol=-1438.200 rho,g/cc=0.720 C 50 H 102
""".format(fuelTemperature, fuelTemperature)
add_new_fuel('SASOLWAX907_CARBONBLACK', card_str)
# cea = CEA_Obj(
# oxName="NITROUS_COOLPROP",
# fuelName="SASOLWAX907_CARBONBLACK"
# )
# s = cea.get_full_cea_output(Pc=combustionPressure/1e5, MR=mixtureRatio, eps=expansionRatio, pc_units="bar", output='siunits')
# print(s)
#
# pass
with hiddenPrints:
cea = CEA_Obj_W_Units(oxName="NITROUS_COOLPROP",
fuelName="SASOLWAX907_CARBONBLACK",
pressure_units='Pa',
cstar_units='m/s',
temperature_units='K',
sonic_velocity_units='m/s',
enthalpy_units='J/kg',
density_units='kg/m^3',
specific_heat_units='J/kg-K',
viscosity_units='poise',
thermal_cond_units="W/cm-degC")
Isp, mode = cea.estimate_Ambient_Isp(Pc=combustionPressure,
MR=mixtureRatio,
eps=expansionRatio,
Pamb=ambientPressure)
IspVac, Cstar, Tc, MW, gamma = cea.get_IvacCstrTc_ChmMwGam(
Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
# cea = CEA_Obj(
# oxName=oxidizerCard,
# fuelName="SASOLWAX907_CARBONBLACK"
# )
# s = cea.get_full_cea_output(Pc=combustionPressure/1e5, MR=mixtureRatio, eps=expansionRatio, pc_units="bar", output='siunits')
# print(s)
return Isp, CpAve, MolWt, Cstar, Tc, gamma
from rocketcea.cea_obj import CEA_Obj, add_new_fuel, add_new_oxidizer, add_new_propellant card_str = """ fuel NASA_RP-1 C 1.0 H 1.95 wt%=100.00 h,cal=-5907.672 t(k)=298.15 rho=.773 """ add_new_fuel( 'NASA_RP_1', card_str ) C = CEA_Obj(oxName="GOX", fuelName="NASA_RP_1") s = C.get_full_cea_output( Pc=1000.0, MR=3.0, eps=40.0, short_output=1) print( s )
def getPerformanceParameters(self, combustionPressure, ambientPressure, oxidizerTemperature, expansionRatio, mixtureRatio):
import CoolProp.CoolProp as CP
from rocketcea.cea_obj import CEA_Obj, add_new_fuel, add_new_oxidizer, add_new_propellant
from rocketcea.cea_obj_w_units import CEA_Obj as CEA_Obj_W_Units
from rocketcea.blends import makeCardForNewTemperature
combustionPressure = max(10, combustionPressure) # Limitation of the library...
fuelTemperature = 293
HMOLAR = CP.PropsSI('HMOLAR','T',oxidizerTemperature,'P',combustionPressure,"N2O") / 1e3
oxidizerDensity = CP.PropsSI('D','T',oxidizerTemperature,'P',combustionPressure,"N2O")
RHO = oxidizerDensity * 1e3 / (1e2 * 1e2 * 1e2)
oxid_card_str = """
oxid=NITROUS wt=1.0 t,K={:.2f} h,kj/mol={:.2f} rho,g/cc={:.2f} N 2 O 1
""".format(oxidizerTemperature, HMOLAR, RHO)
fuel_card_str = """
fuel=C(gr) wt={:.4f} t,K={:.2f}
fuel=SASOL907 wt={:.4f} t,K={:.2f} h,kj/mol={:.2f} rho,g/cc={:.3f} C 50 H 102
""".format(
assumptions.carbonBlackFraction.get(),
fuelTemperature,
1 - assumptions.carbonBlackFraction.get(),
fuelTemperature,
assumptions.fuelEnthalpyOfFormation.get(),
assumptions.fuelDensityLiquid.get() / 1e3)
problemString = "Pc={:.2f},Pa={:.2f},To={:.2f},Tf={:.2f},ER={:.2f},MR={:.2f},oxid={:},fuel={:}".format(
combustionPressure,
ambientPressure,
oxidizerTemperature,
fuelTemperature,
expansionRatio,
mixtureRatio,
oxid_card_str,
fuel_card_str
)
strHash = hashlib.md5(problemString.encode()).hexdigest()
NasaCEA.totalHits = NasaCEA.totalHits + 1
if options.enableCeaLookup and strHash in NasaCEA.inMemoryCache:
# print("Hit cache")
NasaCEA.cacheHits = NasaCEA.cacheHits + 1
return NasaCEA.inMemoryCache[strHash]
# print(HMOLAR, RHO)
add_new_oxidizer('NITROUS_COOLPROP', oxid_card_str)
add_new_fuel('SASOLWAX907_CARBONBLACK', fuel_card_str)
with hiddenPrints:
combustionPressure = round(combustionPressure, 2)
mixtureRatio = round(mixtureRatio, 2)
expansionRatio = round(expansionRatio, 2)
ambientPressure = round(ambientPressure, 2)
cea = CEA_Obj_W_Units(
oxName="NITROUS_COOLPROP",
fuelName="SASOLWAX907_CARBONBLACK",
pressure_units='Pa',
cstar_units='m/s',
temperature_units='K',
sonic_velocity_units='m/s',
enthalpy_units='J/kg',
density_units='kg/m^3',
specific_heat_units='J/kg-K',
viscosity_units='poise',
thermal_cond_units="W/cm-degC"
)
Isp,mode = cea.estimate_Ambient_Isp(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio, Pamb=ambientPressure)
IspVac, Cstar, Tc, MW, gamma = cea.get_IvacCstrTc_ThtMwGam(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
Cp = cea.get_Chamber_Cp(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
rho = cea.get_Chamber_Density(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
CfVac, Cf, mode = cea.get_PambCf(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
PcOvPe = cea.get_PcOvPe(Pc=combustionPressure, MR=mixtureRatio, eps=expansionRatio)
exitPressure = combustionPressure / PcOvPe
result = (Isp, Cp, MW, Cstar, Tc, gamma, rho, Cf, exitPressure, oxidizerDensity)
if options.enableCeaLookup:
NasaCEA.inMemoryCache[strHash] = result
return result
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)
plt.xlabel(xname)
plt.ylabel(yname)
plt.title(plttit)
plt.legend(loc="lower right")
plt.savefig(pltname)
plt.close
### ANALYSIS SET UP ###
# defining fuel will add it's information to the master list of fuels to run rocketCEA with.
# define PMMA
card_str = '''
fuel PMMA C 5 H 8 O 2
h,kj=-430.5 t(k)=299.82
''' # Greg Zilliac's recommendation for modeling PMMA
add_new_fuel('PMMA',
card_str) # rocketCEA function to add PMMA to possible inputs
# define HTPB
card_str2 = '''
fuel HTPB C 7.3165 H 10.3360 O 0.1063
h,kj/mol= 456 t(k)=298.15 rho=0.9220
'''
add_new_fuel('HTPB',
card_str2) # rocketCEA function to add HTPB to possible inputs
# define ABS (monomer of ABS)
card_str3 = '''
fuel ABS C 3 H 3 N 1
h,kj/mol=172 t(k)=299.82
'''
add_new_fuel('ABS (Monomer)',