def test_mr_temperature_limits_2(self):
mc = MR_Temperature_Limits(oxName='MON12',
fuelName='M10',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=1000.0)
self.assertAlmostEqual(mc.max_MR, 85.131, places=3)
def test_mr_temperature_limits_3(self):
mc = MR_Temperature_Limits(oxName=['F2', 'O2'],
fuelName=["N2H4", "NH3"],
oxPcentL=[65, 35],
fuelPcentL=[90, 10],
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=1000.0)
self.assertAlmostEqual(mc.max_MR, 79.5403, places=3)
def test_mr_temperature_limits_1(self):
mc = MR_Temperature_Limits(oxName='N2O4',
fuelName='NH3',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=1000.0)
self.assertAlmostEqual(mc.max_MR, 35.3561, places=3)
def test_mr_temperature_limits_1b(self):
mc = MR_Temperature_Limits(oxName='N2O4',
fuelName='NH3',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=10.0)
self.assertAlmostEqual(mc.max_MR, 10, places=3)
s = str(mc)
self.assertEqual(
s,
'<N2O4/NH3, Stoich_MR=2.02602, Min MR=0.332277, Max MR=10, Tc Left=1000 R, Tc Right=2506.12 R>'
)
def __init__(self,
figsize=(10, 8),
dpi=70,
Pc=500.,
eps=20.,
nsteps_sg=100,
nsteps_isp=100,
legend_loc='best',
show_mr_on_plot=False,
show_frozen_isp_on_plot=False,
bipropL=None,
monopropL=None,
spec_gravD=None):
if bipropL is None:
bipropL = [('LOX', 'LH2'), ('N2O4', 'MMH'), ('LOX', 'RP1'),
('FLOX80', 'CH4'), ('IRFNA', 'MHF3'), ('LOX', 'CH4'),
('F2', 'H2'), ('F2', 'N2H4'), ('CLF5', 'N2H4'),
('N2F4', 'N2H4')]
self.figsize = figsize
self.dpi = dpi
self.Pc = Pc
self.eps = eps
self.headline = 'Pc=%g psia, Area Ratio=%g:1' % (self.Pc, self.eps)
self.nsteps_sg = nsteps_sg # controls grid on plot for interplating stage properties
self.nsteps_isp = nsteps_isp
# 'best', 'upper right', 'right', 'center', 'lower center', 'center right', etc.
self.legend_loc = legend_loc
self.show_mr_on_plot = show_mr_on_plot
self.show_frozen_isp_on_plot = show_frozen_isp_on_plot
self.bipropL = bipropL
if monopropL is None:
monopropL = []
self.monopropL = monopropL
self.monoprop_sgIspD = {} #index:name, value:(sg, Isp)
self.fig = plt.figure(figsize=figsize, dpi=dpi) # figsize=(NxM) inches
self.added_props_to_plot = False
if spec_gravD is not None:
for key, val in spec_gravD.items():
add_prop_sg(name, val)
self.mr_objL = []
self.isp_min = 9999.0 # initialize extents of plot
self.isp_max = 0.0
self.sg_min = 9999.0
self.sg_max = 0.0
for (oxName, fuelName) in bipropL:
if not got_sg(oxName):
raise Exception('%s Specific Gravity Missing...\n'%oxName +\
' add to spec_gravD["%s"]'%oxName)
if not got_sg(fuelName):
raise Exception('%s Specific Gravity Missing...\n'%fuelName +\
' add to spec_gravD["%s"]'%fuelName)
tobj = MR_Temperature_Limits(oxName=oxName,
fuelName=fuelName,
TC_LIMIT=1500.0,
PcNominal=Pc,
epsNominal=eps,
MR_MIN=0.0,
MR_MAX=200.0)
self.mr_objL.append(MR_Peak_At_EpsPc(tobj, pc=Pc, eps=eps))
add_sg_isp_to_mr_obj(self.mr_objL[-1])
if show_frozen_isp_on_plot:
add_frozen_isp_to_mr_obj(self.mr_objL[-1], Pc=Pc, eps=eps)
self.isp_min = min(self.isp_min, self.mr_objL[-1].isp_min)
self.isp_max = max(self.isp_max, self.mr_objL[-1].isp_max)
self.sg_min = min(self.sg_min, self.mr_objL[-1].sg_min)
self.sg_max = max(self.sg_max, self.mr_objL[-1].sg_max)
for propName in self.monopropL:
sg = get_sg(propName)
if sg is not None:
self.sg_min = min(self.sg_min, sg)
self.sg_max = max(self.sg_max, sg)
ispObj = CEA_Obj(propName=propName)
Isp = ispObj.get_Isp(Pc=Pc, eps=eps)
self.isp_min = min(self.isp_min, Isp)
self.isp_max = max(self.isp_max, Isp)
self.monoprop_sgIspD[propName] = (sg, Isp)
self.rhobRange = self.sg_max - self.sg_min
self.ispRange = self.isp_max - self.isp_min
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()
from rocketisp.geometry import Geometry
from rocketisp.efficiencies import Efficiencies
from rocketisp.stream_tubes import CoreStream
from rocketisp.rocket_isp import RocketThruster
oxName = 'N2O4'
fuelName = 'MMH'
Fvac = 100 # lbf
Pc = 100 # psia
eps = 100
pcentBell = 80
mc = MR_Temperature_Limits(oxName=oxName,
fuelName=fuelName,
PcNominal=Pc,
epsNominal=eps,
TC_LIMIT=1000.0,
MR_MIN=0.0,
MR_MAX=1000.0)
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())
return self._mrRightOfPeak
def get_peak_mr_vs_isp_lists(self, Npts=20):
mrL = list(np.linspace(self.mrLeftOfPeak, self.mrRightOfPeak, Npts))
ispL = [self.isp_at_mr(mr=mr) for mr in mrL]
return mrL, ispL
if __name__ == "__main__":
from pylab import *
mc = MR_Temperature_Limits(oxName='F2',
fuelName='H2',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1400.0,
PcNominal=200.0,
epsNominal=3.0,
MR_MIN=0.0,
MR_MAX=1000.0)
print('Stoich MR =', mc.Stoich_MR,
'for %s/%s' % (mc.cea_oxName, mc.cea_fuelName))
print()
print('Min MR = %g' % mc.min_MR, ' Tc at Min MR =', mc.Tc_at_min_MR)
print('Max MR = %g' % mc.max_MR, ' Tc at Max MR =', mc.Tc_at_max_MR)
mrcurve = MR_Peak_At_EpsPc(mc, pc=1000., eps=10.,
ispType='CEAFROZEN') #'CEAFROZEN' )
print('Peak IspODE=%g sec at MR =' % mrcurve.ispPeak, mrcurve.mrPeak)
print()
print('MR at 97% Isp (on low side) =', mrcurve.mrLeftOfPeak)
from rocketcea.biprop_utils.mr_t_limits import MR_Temperature_Limits
mc = MR_Temperature_Limits(oxName='N2O4',
fuelName='NH3',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=10.0)
print('Stoich MR =', mc.Stoich_MR,
'for %s/%s' % (mc.cea_oxName, mc.cea_fuelName))
print('Min MR = %g' % mc.min_MR, ' Tc at Min MR =', mc.Tc_at_min_MR)
print('Max MR = %g' % mc.max_MR, ' Tc at Max MR =', mc.Tc_at_max_MR)
print(str(mc))
print('')
mc = MR_Temperature_Limits(oxName='MON12',
fuelName='M10',
oxPcentL=None,
fuelPcentL=None,
TC_LIMIT=1000.0,
PcNominal=1000.0,
epsNominal=10.0,
MR_MIN=0.0,
MR_MAX=1000.0)
print('Stoich MR =', mc.Stoich_MR,
'for %s/%s' % (mc.cea_oxName, mc.cea_fuelName))