def test_check_FFC_Isp_values(self):
"""test check FFC Isp values"""
geomObj = Geometry(Rthrt=1,
CR=2.5,
eps=62.5,
pcentBell=75,
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=None)
effObj = Efficiencies()
effObj.set_const(
'ERE', 0.98) # don't know injector details so set effERE=0.98
# It's an ablative chamber, so some FFC (fuel film cooling) is required... guess about 10%
C = CoreStream(geomObj=geomObj,
effObj=effObj,
pcentFFC=10.0,
Pamb=0.001,
oxName='N2O4',
fuelName='A50',
MRcore=1.6,
Pc=100)
C.reset_attr('Pc', 100)
self.assertAlmostEqual(C('IspDel'), 325.64723, places=2)
self.assertAlmostEqual(C('IspODE'), 338.9201, places=2)
self.assertAlmostEqual(C('IspODF'), 320.4940, places=2)
def __init__(self,
name='RocketIsp Thruster',
coreObj=CoreStream(),
injObj=None,
noz_regen_eps=1.0,
pulse_sec=float('inf'),
pulse_quality=0.8,
isRegenCham=False,
calc_CdThroat=True):
"""
Calculate delivered thrust chamber Isp by simplified JANNAF method.
"""
self.name = name
self.coreObj = coreObj
self.geomObj = coreObj.geomObj
self.injObj = injObj
#self.iprop = coreObj.oxName + '/' + coreObj.fuelName
self.pulse_sec = pulse_sec
self.pulse_quality = pulse_quality
self.noz_regen_eps = noz_regen_eps
self.isRegenCham = isRegenCham
self.calc_CdThroat = calc_CdThroat
self.calc_all_eff()
def test_check_Isp_values(self):
"""test check Isp values"""
C = CoreStream(geomObj=Geometry(eps=35),
effObj=Efficiencies(ERE=0.98, Noz=0.97),
oxName='LOX',
fuelName='CH4',
MRcore=3.6,
Pc=500,
Pamb=14.7)
self.assertAlmostEqual(C('IspAmb'), 251.9288, places=2)
self.assertAlmostEqual(C('IspDel'), 345.2795, places=2)
self.assertAlmostEqual(C('IspODE'), 363.2227, places=2)
self.assertAlmostEqual(C('IspODF'), 334.1623, places=2)
C.reset_CdThroat(C.CdThroat)
C.reset_attr('Pamb', C.Pexit + 0.06, re_evaluate=True)
C.reset_attr('Pamb', C.Pexit, re_evaluate=True)
C.reset_attr('Pamb', 15, re_evaluate=True)
def test_overall_Isp_efficiency(self):
"""test overall Isp efficiency"""
G = Geometry(Rthrt=5.978,
CR=2.5,
eps=62.5,
pcentBell=75,
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=None)
C = CoreStream(geomObj=G,
effObj=Efficiencies(ERE=0.98, Noz=0.96515),
pcentFFC=10.0,
oxName='N2O4',
fuelName='A50',
MRcore=1.6,
Pc=100,
Pamb=0.0)
I = Injector(
C,
Tox=None,
Tfuel=None,
elemEm=0.8,
fdPinjOx=0.25,
fdPinjFuel=0.25,
dpOxInp=None,
dpFuelInp=None,
setNelementsBy=
'acoustics', # can be "acoustics", "elem_density", "input"
elemDensInp=5,
NelementsInp=100,
OxOrfPerEl=1.0,
FuelOrfPerEl=1.0,
lolFuelElem=True,
setAcousticFreqBy='mode', # can be "mode" or "freq"
desAcousMode='2T',
desFreqInp=5000,
CdOxOrf=0.75,
CdFuelOrf=0.75,
dropCorrOx=0.33,
dropCorrFuel=0.33,
DorfMin=0.008,
LfanOvDorfOx=20.0,
LfanOvDorfFuel=20.0)
self.assertAlmostEqual(I('MolWtOx'), 92.011, places=1)
def __init__(self, name='PI Thruster', geomObj=Geometry(), ERE=0.98,
oxName='N2O4', fuelName='MMH', MRcore=1.9, Pc=500,
isRegenCham=0, noz_regen_eps=1.0, calc_CdThroat=True):
# create a perfect injector CoreStream
coreObj = CoreStream( geomObj=geomObj,
effObj=Efficiencies(ERE=ERE),
oxName=oxName, fuelName=fuelName,
MRcore=MRcore, Pc=Pc)
self.R = RocketThruster( name=name,
coreObj=coreObj, injObj=None,
isRegenCham=isRegenCham, noz_regen_eps=noz_regen_eps,
calc_CdThroat=calc_CdThroat)
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=16)
effObj = Efficiencies()
#effObj.set_const('ERE', 0.98)
core = CoreStream(geomObj,
effObj,
oxName='N2O4',
fuelName='MMH',
MRcore=1.85,
Pc=150,
CdThroat=0.995,
pcentFFC=14.0,
ko=0.035)
inj = Injector(
core,
Tox=None,
Tfuel=None,
elemEm=0.9,
fdPinjOx=0.25,
fdPinjFuel=0.25,
elemDensInp=None,
NelementsInp=None,
setNelementsBy='acoustics', # can be "acoustics", "density", "input"
from rocketisp.rocket_isp import RocketThruster
from rocketisp.geometry import Geometry
from rocketisp.stream_tubes import CoreStream
from rocketisp.efficiencies import Efficiencies
from rocketisp.examples.compare_vals import compare_header, compare
geomObj = Geometry(Rthrt=3,
CR=2.5, eps=55, pcentBell=80,
RupThroat=1.5, RdwnThroat=1.0, RchmConv=1.0, cham_conv_deg=30,
LchmOvrDt=3.10, LchmMin=2.0, LchamberInp=None)
effObj = Efficiencies()
effObj.set_const('ERE', 0.97 )
core = CoreStream( geomObj=geomObj, effObj=effObj,
oxName='N2O4', fuelName='MMH',
MRcore=1.65, Pc=125, pcentFFC=4.5 )
R = RocketThruster(name='Shuttle OMS',coreObj=core, injObj=None)
R.scale_Rt_to_Thrust( 6000 , Pamb=0.0 )
R.set_MRthruster( MRthruster=1.65 )
R.scale_Rt_to_Thrust( 6000 , Pamb=0.0 )
compare_header()
compare('Fvacuum',6000, core('FvacTotal'))
compare('Isp Vacuum', 313.2, core('IspDel'))
compare('Engine Length', 77, geomObj('Ltotal'))
compare('Nozzle ID', 43.09, geomObj('Rexit')*2)
#R.summ_print()
from rocketisp.rocket_isp import RocketThruster
from rocketisp.geometry import Geometry
from rocketisp.stream_tubes import CoreStream
from rocketisp.efficiencies import Efficiencies
from rocketisp.examples.compare_vals import compare_header, compare
geomObj = Geometry(Rthrt=Rthrt,
CR=(5.131/2.4724)**2, eps=eps, pcentBell=70,
RupThroat=1.5, RdwnThroat=1.0, RchmConv=1.0, cham_conv_deg=30,
LchmOvrDt=2.4842/2, LchmMin=2.0, LchamberInp=15.0)
effObj = Efficiencies()
effObj.set_const('ERE', 0.9892 )
core = CoreStream( geomObj, effObj, oxName='LOX', fuelName='LH2', MRcore=MRcore,
Pc=Pc, CdThroat=CdThroat)
R = RocketThruster(name='RL10',coreObj=core, injObj=None, calc_CdThroat=False,
noz_regen_eps=eps)
R.scale_Rt_to_Thrust( Fvac, Pamb=0.0 , use_scipy=False )
compare_header()
compare('Fvacuum',Fvac, core('FvacTotal'))
compare('Isp Vacuum', Isp, core('IspDel'))
compare('Cstar ODE', cstarODE, core('cstarODE'))
print()
compare('Fuel Flow Rate', wdotFuel, core('wdotFlCore'))
compare('Ox Flow Rate', wdotOx, core('wdotOxCore'))
CR=2.5,
eps=40,
pcentBell=90,
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=None)
effObj = Efficiencies()
core = CoreStream(geomObj=geomObj,
effObj=effObj,
oxName='LOX',
fuelName='CH4',
MRcore=3.6,
Pc=4786)
R = RocketThruster(name='SpaceX Raptor', coreObj=core, injObj=None)
R.scale_Rt_to_Thrust(500000, Pamb=0.0)
compare_header()
compare('Fvacuum', 500000, core('FvacTotal'))
compare('Isp Vacuum', 380, core('IspDel'))
core.reset_attr('Pamb', 14.7, re_evaluate=True)
compare('Isp SeaLevel', 330, core('IspAmb'))
core.reset_attr('Pamb', 0, re_evaluate=True)
from rocketisp.geometry import Geometry
from rocketisp.stream_tubes import CoreStream
from rocketisp.efficiencies import Efficiencies
# create basic Geometry.
# Use "place-holder" of 1 inch for throat radius... correct later with "scale_Rt_to_Thrust"
geomObj = Geometry(Rthrt=1,
CR=2.5, eps=62.5, pcentBell=72.3,
RupThroat=1.5, RdwnThroat=1.0, RchmConv=1.0, cham_conv_deg=30,
LchmOvrDt=3.10, LchmMin=2.0, LchamberInp=None)
effObj = Efficiencies()
effObj.set_const('ERE', 0.98) # don't know injector details so set effERE=0.98
# It's an ablative chamber, so some FFC (fuel film cooling) is required... guess about 15%
core = CoreStream( geomObj=geomObj, effObj=effObj, pcentFFC=15.0,
oxName='N2O4', fuelName='A50', MRcore=1.6, Pc=100 )
R = RocketThruster(name='Apollo SPS',coreObj=core)
# scale geometry to give 20,500 lbf of thrust for current conditions
R.scale_Rt_to_Thrust( 20500 , Pamb=0.0 )
# figure out best mixture ratio to run the engine.
R.set_mr_to_max_ispdel()
# re-scale geometry to give 20,500 lbf of thrust after MR change
R.scale_Rt_to_Thrust( 20500 , Pamb=0.0 )
fsave = 'Apollo_SPS.html'
fOut = open(fsave , 'w')
fOut.write( R.get_html_file_str() )
Rt = (At / pi)**0.5
#print( 'Calculated MR =', wdOx / wdFuel )
dpOxInp=160
dpFuelInp=100
geomObj = Geometry(Rthrt=Rt,
CR=CR, eps=eps, pcentBell=pcentBell,
RupThroat=0.5, RdwnThroat=1.0, RchmConv=0.5, cham_conv_deg=30,
LchmOvrDt=3, LchmMin=2.0, LchamberInp=Lcham)
effObj = Efficiencies()
effObj.set_const('ERE', 0.975 )
core = CoreStream( geomObj, effObj, oxName=oxName, fuelName=fuelName, MRcore=MR,
Pc=Pc, Pamb=14.7, CdThroat=1.0,
adjCstarODE=0.992801, adjIspIdeal=1.01876)
C = RocketThruster(name='Huzel A-2',coreObj=core, injObj=None, calc_CdThroat=False)
#C.scale_Rt_to_Thrust( Fvac, Pamb=0 , use_scipy=False )
compare_header()
compare('Fvacuum',Fvac, core('FvacTotal'))
compare('CfVacDesign', CfVacDesign, core('CfVacDel'))
print()
compare('Efficiency Cstar/ERE', effCstar, effObj('ERE'))
compare('Cstar ODE', cstarODE, core('cstarODE'))
from rocketisp.geometry import Geometry
from rocketisp.efficiencies import Efficiencies
from rocketisp.stream_tubes import CoreStream
from rocketisp.rocket_isp import RocketThruster
C = CoreStream( geomObj=Geometry(eps=35),
effObj=Efficiencies(ERE=0.99),
oxName='LOX', fuelName='LH2', MRcore=6,
Pc=500, Pamb=0)
R = RocketThruster(name='Example 6K Thruster', coreObj=C)
R.scale_Rt_to_Thrust( 6000 , Pamb=0.0 )
R.summ_print()
"""
model the XLR-134
"""
from rocketisp.rocket_isp import RocketThruster
from rocketisp.geometry import Geometry
from rocketisp.stream_tubes import CoreStream
from rocketisp.efficiencies import Efficiencies
geomObj = Geometry(Rthrt=1,
CR=3.0, eps=767.9, pcentBell=80,
RupThroat=1.5, RdwnThroat=1.0, RchmConv=1.0, cham_conv_deg=30,
LchmOvrDt=3.10, LchmMin=2.0, LchamberInp=None)
effObj = Efficiencies()
effObj.set_const('ERE', (490.45-8.6)/490.45)
core = CoreStream( geomObj, effObj, oxName='LOX', fuelName='LH2', MRcore=6.0,
Pc=510 )
R = RocketThruster(name='xlr134',coreObj=core, injObj=None)
R.scale_Rt_to_Thrust( 500 , Pamb=0.0 , use_scipy=False )
R.summ_print()
RdwnThroat=1.0,
RchmConv=0.5,
cham_conv_deg=30,
LchmOvrDt=3,
LchmMin=2.0,
LchamberInp=Lcham)
effObj = Efficiencies()
effObj.set_const('ERE', 0.975)
effObj.set_const('Noz', 0.933177) # Huzel based on frozen Isp
core = CoreStream(geomObj,
effObj,
oxName=oxName,
fuelName=fuelName,
MRcore=MR,
Pc=Pc,
Pamb=14.7,
CdThroat=1.0,
adjCstarODE=0.978196,
adjIspIdeal=1.0084418978404621)
C = RocketThruster(name='Huzel A-1', coreObj=core, calc_CdThroat=False)
#C.scale_Rt_to_Thrust( FseaLevel, Pamb=15 , use_scipy=False )
compare_header()
compare('FseaLevel', FseaLevel, core('Fambient'))
compare('CfVacDesign', CfVacDesign, core('CfVacDel'))
compare('CfAmbDel', CfAmbDel, core('CfAmbDel'))
pcentBell=80,
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=None)
effObj = Efficiencies()
# It's an ablative chamber, so some FFC (fuel film cooling) is required... guess about 10%
C = CoreStream(geomObj=geomObj,
effObj=effObj,
pcentFFC=0.0,
Pamb=0.0,
oxName='N2O4',
fuelName='MMH',
MRcore=1.9,
Pc=500)
I = Injector(
C,
Tox=None,
Tfuel=None,
elemEm=0.8,
fdPinjOx=0.25,
fdPinjFuel=0.25,
elemDensInp=None,
NelementsInp=None,
setNelementsBy='acoustics', # can be "acoustics", "density", "input"
setAcousticFreqBy='mode', # can be "mode" or "freq"
from rocketisp.geometry import Geometry
from rocketisp.efficiencies import Efficiencies
from rocketisp.stream_tubes import CoreStream
C = CoreStream(geomObj=Geometry(eps=35),
effObj=Efficiencies(ERE=0.98, Noz=0.97),
oxName='LOX',
fuelName='CH4',
MRcore=3.6,
Pc=500,
Pamb=14.7)
for name in ['IspODE', 'IspDel', 'IspODF']:
print('%8s =' % name, '%.1f' % C(name))
print('%8s =' % 'IspAmb', '%.1f' % C('IspAmb'), C('noz_mode'))
C.summ_print()
def calc_ODE_ODK_FROZ_isp(oxName='N2O4',
fuelName='MMH',
Pc=1000.0,
eps=10.0,
pcentBell=80.0,
Fvac=1000.0,
NumRuns=20,
do_show=True):
# ============ use RocketCEA to find MR range ===================
mc = MR_Temperature_Limits(oxName=oxName,
fuelName=fuelName,
PcNominal=Pc,
epsNominal=eps)
mr_peak = MR_Peak_At_EpsPc(
mc,
pc=Pc,
eps=eps,
ispType='CEAODE', # ispType can be CEAODE, CEAFROZEN
NterpSize=100)
print('Peak IspODE=%g sec at MR =' % mr_peak.ispPeak, mr_peak.mrPeak)
print()
print('MR at 97% Isp (on low side) =',
mr_peak.calc_mrLow_minus_NPcentIsp())
print('MR at 97% Isp (on high side) =',
mr_peak.calc_mrHigh_minus_NPcentIsp())
mr_lo = round(
mr_peak.mrLeftOfPeak -
(mr_peak.mrRightOfPeak - mr_peak.mrLeftOfPeak) / 10.0, 2)
mr_hi = round(mr_peak.mrRightOfPeak, 2)
delMR = (mr_hi - mr_lo) / (NumRuns - 1)
# ===============================
geomObj = Geometry(Rthrt=5.868 / 2,
CR=2.5,
eps=eps,
pcentBell=pcentBell,
RupThroat=1.5,
RdwnThroat=1.0,
RchmConv=1.0,
cham_conv_deg=30,
LchmOvrDt=3.10,
LchmMin=2.0,
LchamberInp=16)
core = CoreStream(geomObj,
oxName=oxName,
fuelName=fuelName,
MRcore=1.6,
Pc=Pc)
R = RocketThruster(name='sample', coreObj=core, injObj=None)
ispodeL = []
ispodkL = []
ispodfL = []
mrL = []
MR = mr_lo
for _ in range(NumRuns):
mrL.append(MR)
core.reset_attr('MRcore', MR, re_evaluate=True)
R.scale_Rt_to_Thrust(Fvac, Pamb=0.0, use_scipy=False)
ispodeL.append(R.coreObj.IspODE)
ispodkL.append(R.coreObj.IspODK)
ispodfL.append(R.coreObj.IspODF)
MR += delMR
# ======= find peaks ======
mr_ode_terp = InterpProp(mrL, ispodeL)
mr_ode_Peak, isp_ode_peak = gold_search_max(mr_ode_terp,
mrL[0],
mrL[-1],
tol=1.0e-5)
mr_odk_terp = InterpProp(mrL, ispodkL)
mr_odk_Peak, isp_odk_peak = gold_search_max(mr_odk_terp,
mrL[0],
mrL[-1],
tol=1.0e-5)
mr_odf_terp = InterpProp(mrL, ispodfL)
mr_odf_Peak, isp_odf_peak = gold_search_max(mr_odf_terp,
mrL[0],
mrL[-1],
tol=1.0e-5)
fig, ax = plt.subplots(figsize=(8, 6))
plt.plot(mrL, ispodeL, label='IspODE', color=COLORL[0])
plt.plot(mrL, ispodkL, label='IspODK', color=COLORL[1])
plt.plot(mrL, ispodfL, label='IspODF', color=COLORL[2])
# show ========= optimum MR difference ========
def span_mrpeak(isL):
minpt = min(isL)
maxpt = max(isL)
span = maxpt - minpt
return [maxpt - 0.8 * span, maxpt]
plt.plot([mr_ode_Peak, mr_ode_Peak],
span_mrpeak(ispodeL),
'--',
label='MRode=%.2f' % mr_ode_Peak,
linewidth=2,
color=COLORL[0])
plt.plot([mr_odk_Peak, mr_odk_Peak],
span_mrpeak(ispodkL),
'--',
label='MRodk=%.2f' % mr_odk_Peak,
linewidth=2,
color=COLORL[1])
plt.plot([mr_odf_Peak, mr_odf_Peak],
span_mrpeak(ispodfL),
'--',
label='MRodf=%.2f' % mr_odf_Peak,
linewidth=2,
color=COLORL[2])
isp_odk_peak = abs(isp_odk_peak)
plt.text(mr_odk_Peak,
isp_odk_peak,
'%i' % int(isp_odk_peak),
ha='left',
va='bottom',
transform=ax.transData,
color=COLORL[1])
plt.legend()
plt.ylabel('Isp (sec)')
plt.xlabel('Mixture Ratio')
plt.title( "%s/%s RocketIsp ODE ODK ODF\nFvac=%.0f lbf, Pc=%.0f psia, AR=%.0f:1, %%Bell=%.0f%%"%\
(oxName, fuelName, Fvac, Pc, eps, pcentBell))
png_name = 'odekf_%s_%s_Fvac%g_Pc%g_eps%g.png' % (oxName, fuelName, Fvac,
Pc, eps)
plt.savefig(png_name, dpi=120)
if do_show:
plt.show()
print('MR at 97% Isp (on low side) =', mr_peak.calc_mrLow_minus_NPcentIsp())
print('MR at 97% Isp (on high side) =', mr_peak.calc_mrHigh_minus_NPcentIsp())
mr_lo = round(
mr_peak.mrLeftOfPeak -
(mr_peak.mrRightOfPeak - mr_peak.mrLeftOfPeak) / 10.0, 2)
mr_hi = round(mr_peak.mrRightOfPeak, 2)
print('mr_lo =', mr_lo)
print('mr_hi =', mr_hi)
# =========== create RocketIsp structures
# create CoreStream with area ratio=375:1, Pc=137, FFC=30% and effERE=0.99
C = CoreStream(geomObj=Geometry(eps=eps),
effObj=Efficiencies(ERE=1.0, Div=1.0, BL=1.0, TP=1.0),
pcentFFC=0,
oxName=oxName,
fuelName=fuelName,
MRcore=mr_lo,
Pc=Pc,
Pamb=0)
# instantiate RocketThruster
R = RocketThruster(name='Sample Thruster', coreObj=C)
R.scale_Rt_to_Thrust(ThrustLbf=Fvac, Pamb=0.0)
#R.summ_print()
# =========================================================
# generate data
ispodeL = [] # list of IspODE (one-dimensional equilibrium)
ispodkL = [] # list of IspODK (one-dimensional kinetic)
ispodfL = [] # list of IspODF (frozen)
mrcoreL = [] # list of MRcore (core stream tube mixture ratio)
for MRcore in np.linspace(mr_lo, mr_hi, num=60):
"""
Create an HTML summary page and launch webbrowser to show summary.
"""
import webbrowser
import os
from rocketisp.geometry import Geometry
from rocketisp.efficiencies import Efficiencies
from rocketisp.stream_tubes import CoreStream
from rocketisp.rocket_isp import RocketThruster
# create CoreStream with area ratio=375:1, Pc=137, FFC=30% and effERE=0.99
C = CoreStream(geomObj=Geometry(eps=375),
effObj=Efficiencies(ERE=0.99),
pcentFFC=30,
oxName='N2O4',
fuelName='N2H4',
MRcore=1.26,
Pc=137,
Pamb=0)
# instantiate RocketThruster
R = RocketThruster(name='100 lbf Aerojet HiPAT R-4D', coreObj=C)
R.scale_Rt_to_Thrust(100, Pamb=0.0)
#R.summ_print()
fsave = 'hipat_at_opt_mr.html'
fOut = open(fsave, 'w')
fOut.write(R.get_html_file_str())
fOut.close()
IspSL = 366 # sec
cstarODE = xxx / 12.0 # ft/sec
eps = 77.5
CR = 3.0
Lnoz = 121 # in
geomObj = Geometry(Rthrt=Rthrt,
CR=CR, eps=eps, pcentBell=80, LnozInp=Lnoz,
RupThroat=1.0, RdwnThroat=0.392, RchmConv=1.73921, cham_conv_deg=25.42,
LchmOvrDt=2.4842/2, LchmMin=2.0, LchamberInp=None)
effObj = Efficiencies()
effObj.set_const('ERE', 0.99 )
core = CoreStream( geomObj, effObj, oxName='LOX', fuelName='LH2', MRcore=MRcore, Pc=Pc)
R = RocketThruster(name='SSME, RS-25',coreObj=core, injObj=None, pulse_sec=float('inf'), pulse_quality=0.8)
R.scale_Rt_to_Thrust( Fvac , Pamb=0.0 , use_scipy=False )
compare_header()
compare('Fvacuum',Fvac, core('FvacTotal'))
compare('Isp Vacuum', Isp, core('IspDel'))
core.reset_attr( 'Pamb', 14.7, re_evaluate=True)
compare('Isp SeaLevel', IspSL, core('IspAmb'))
compare('FseaLevel', FseaLevel, core('Fambient'))
core.reset_attr( 'Pamb', 0, re_evaluate=True)