def estimate_Ambient_Isp(self, Pc=100.0, MR=1.0, eps=40.0, Pamb=14.7):
"""::
#: return the tuple (IspAmb, mode)
#: Use throat gam to run ideal separation calculations.
#: mode is a string containing, UnderExpanded, OverExpanded, or Separated
#: MR is only used for ox/fuel combos.
"""
self.setupCards(Pc=Pc, MR=MR, eps=eps)
IspVac = py_cea.rockt.vaci[2]
mw, gam = py_cea.prtout.wm[1], py_cea.prtout.gammas[1] # throat gamma
Cf, CfOverCfvac, mode = ambientCf(gam=gam,
epsTot=eps,
Pc=Pc,
Pamb=Pamb)
IspAmb = IspVac * CfOverCfvac
return IspAmb, mode
Nsteps = 20
ispObj = CEA_Obj(oxName=oxName, fuelName=fuelName)
IspODE, Cstar, Tcomb, mw, gam = ispObj.get_IvacCstrTc_ChmMwGam(Pc=pc,
MR=mr,
eps=eps)
pcArr = [100.0, 150.0, 200.0]
rs = [['Pamb', 'Cf/Cfvac', 'Pc', 'mode']]
for pc in pcArr:
for i in range(Nsteps + 1):
Pamb = 14.7 * i / Nsteps
Cf, CfOverCfvac, mode = separated_Cf.ambientCf(gam=gam,
epsTot=eps,
Pc=pc,
Pamb=Pamb)
rs.append([Pamb, CfOverCfvac, pc, mode])
rs.append(['', '', '', ''])
xl = xlChart.xlChart()
xl.xlApp.DisplayAlerts = 0 # Allow Quick Close without Save Message
myTitle = "%s/%s Ambient Performance at Area Ratio=%.1f\n"%(oxName, fuelName, eps) +\
"Pc Range = %g - %g psia"%(min(pcArr), max(pcArr))
xl.makeChart(rs,
title=myTitle,
nCurves=1,
chartName="Performance",
sheetName="FillData",