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
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'))
R.summ_print()
#geomObj.plot_geometry()
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'))
compare('Cstar Delivered', cstar, core('cstarERE'))
effCfODE = effCfFrozen * core('IspODF') / core('IspODE')
compare('Efficiency Cf/Noz', effCfODE, effObj('Noz'))
print()
compare('Isp Vacuum', Isp, core('IspDel'))
IspFrozen = Isp / effCstar / effCfFrozen
compare('IspODF', IspFrozen, core('IspODF'))
compare('Throat Area', At, geomObj('At'))
compare('Fuel Flow Rate', wdFuel, core('wdotFlCore'))
compare('Ox Flow Rate', wdOx, core('wdotOxCore'))
C.summ_print()