class PerfInjThruster:
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)
def summ_print(self):
self.R.summ_print()
def scale_Rt_to_Thrust(self, ThrustLbf=500.0, Pamb=0.0, use_scipy=False):
"""
Adjust throat size in order to get total thrust at specified ambient pressure exactly
:param ThrustLbf: lbf, desired thrust at specified ambient pressure (Pamb)
:param Pamb: psia, ambient pressure
:param use_scipy: flag to indicate the need for more sophisticated root finder
:type ThrustLbf: float
:type Pamb: float
:type use_scipy: bool
:return: None
:rtype: None """
self.R.scale_Rt_to_Thrust( ThrustLbf=ThrustLbf, Pamb=Pamb, use_scipy=use_scipy )
def set_to_optimum_MR(self):
"""Starting with MR for ER=1 find max Isp MR"""
C = self.R.coreObj # core object
# get MR for equivalence ratio = 1
MRstart = C.ceaObj.getMRforER( ERr=1.0 )
MRlo = MRstart / 3.0
MRhi = MRstart * 3.0
def get_ispdel( MR ):
C.reset_attr('MRcore', MR, re_evaluate=True)
self.R.calc_all_eff()
return C.IspDel
MRopt, IspMax = search_max(get_ispdel, MRlo, MRhi, tol=0.01)
print('MRopt=%g, IspMax=%g sec'%(MRopt, IspMax) )
# use MRopt to reset everything
get_ispdel( MRopt )
return MRopt
R = RocketThruster(name='Sample Thruster',
coreObj=C,
injObj=I,
pulse_sec=float('inf'),
pulse_quality=0.8)
R.set_mr_to_max_ispdel()
ispodeL = [] # list of IspODE (one-dimensional equilibrium)
ispodkL = [] # list of IspODK (one-dimensional kinetic)
ispdelL = [] # list of Isp thruster delivered
MRsave = C.MRcore
for mr in mrcoreL:
R.coreObj.reset_attr('MRcore', mr, re_evaluate=True)
R.calc_all_eff()
ispodeL.append(R.coreObj.IspODE)
ispodkL.append(R.coreObj.IspODK)
ispdelL.append(R.coreObj.IspDel)
R.coreObj.reset_attr('MRcore', MRsave, re_evaluate=True)
R.calc_all_eff()
ispD['ODE'] = ispodeL
ispD['ODK'] = ispodkL
ispD[elemEm] = ispdelL
# ODE Curve
mr_ode_terp = InterpProp(mrcoreL, ispodeL)
mr_ode_Peak, isp_ode_peak = search_max(mr_ode_terp, mrlo, mrhi, tol=1.0e-5)