# Coverage for rocketcea\biprop_utils\veh_stage_obj.py : 12%

## 219 statements 27 run 192 missing 0 excluded

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 | from math import log, exp, log10 from rocketcea.Goal import Goal gc = 32.174 def getRhoVeh( volCuIn ): """Generic equation for scaling stage mass by volume""" if volCuIn <=1.0E-8: print( 'ERROR in volCuIn in getRhoVeh; volCuIn=',volCuIn ) volCuIn = 1.0E-8 # for volume<=0 reset volume tiny so calculated rhoveh is terrible. expon = (log10(volCuIn) + 1.)/(-3.) rhoveh = 10.0**expon return rhoveh class ReferenceStage: '''Scale reference stage to new propellant volume using getRhoVeh correlation''' def calc_rhoVeh(self, vol): return self.corrFactor * getRhoVeh( vol ) @property def MassFrac(self): try: mf = self.WtPropellant / (self.WtPropellant + self.WtInert) except: mf = 0.0 return mf def __init__(self, WtPayload=1600000.0, volCuInRef=75500.0*1728, WtInertRef=300000.0, Name='Saturn V 1st stg'): self.stage_desc = "Wpayload=%g lbm, Mass Scaled from: %s"%(WtPayload, Name) self.Name = Name rhoVeh = WtInertRef / volCuInRef corrRhoStg = getRhoVeh( volCuInRef ) self.corrFactor = rhoVeh / corrRhoStg self.WtPayload = WtPayload self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass def setGLOW(self, GLOW=5000.0, sg=1.0, Isp=300.0): self.GLOW = GLOW rho = sg * 0.0361273 def calc_glow_from_vol( V ): rhoStg = self.calc_rhoVeh(V) return V*(rhoStg + rho) + self.WtPayload G = Goal(goalVal=GLOW, minX=0.01, maxX=(GLOW-self.WtPayload)/rho, verbose=False, funcOfX=calc_glow_from_vol, tolerance=1.0E-10, maxLoops=80, failValue=None) self.VolPropellant, ierror = G() if ierror: self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass else: self.WtPropellant = rho * self.VolPropellant self.WtInert = self.GLOW - self.WtPropellant - self.WtPayload Wbo = self.WtPayload + self.WtInert self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setWtInert(self, WtInert=1000.0, sg=1.0, Isp=300.0): self.WtInert = WtInert rho = sg * 0.0361273 def calc_winert_from_vol( V ): rhoStg = self.calc_rhoVeh(V) return V * rhoStg G = Goal(goalVal=WtInert, minX=0.01, maxX=99.99*WtInert/rho, verbose=False, funcOfX=calc_winert_from_vol, tolerance=1.0E-10, maxLoops=80, failValue=None) self.VolPropellant, ierror = G() if ierror: self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass else: self.WtPropellant = rho * self.VolPropellant Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setWtPropellant(self, WtPropellant=1000.0, sg=1.0, Isp=300.0): self.WtPropellant = WtPropellant rho = sg * 0.0361273 self.VolPropellant = WtPropellant / rho rhoVeh = self.calc_rhoVeh( self.VolPropellant ) self.WtInert = rhoVeh * self.VolPropellant Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setVolPropellant(self, VolPropellant=10000.0, sg=1.0, Isp=300.0): self.VolPropellant = VolPropellant rho = sg * 0.0361273 self.WtPropellant = rho * VolPropellant rhoVeh = self.calc_rhoVeh( self.VolPropellant ) self.WtInert = rhoVeh * self.VolPropellant Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setDeltaV(self, DeltaV=2000.0, sg=1.0, Isp=300.0): self.DeltaV = DeltaV rho = sg * 0.0361273 def calc_dv_from_vol( V ): rhoStg = self.calc_rhoVeh(V) glow = V*(rhoStg + rho) + self.WtPayload wbo = glow - V*rho return gc * Isp * log( glow/wbo ) gam = DeltaV / Isp / gc glow = self.WtPayload * 1000.0 * exp(gam) G = Goal(goalVal=DeltaV, minX=0.01, maxX=glow/rho, verbose=False, funcOfX=calc_dv_from_vol, tolerance=1.0E-10, maxLoops=80, failValue=None) self.VolPropellant, ierror = G() if ierror: self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass else: self.WtPropellant = rho * self.VolPropellant rhoVeh = self.calc_rhoVeh( self.VolPropellant ) self.WtInert = rhoVeh * self.VolPropellant Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant def summ_print(self): try: print('Wp=%g, Vp=%g, Winert=%g, dv=%g, GLOW=%g, mu=%g'%\ (self.WtPropellant, self.VolPropellant, self.WtInert, self.DeltaV, self.GLOW, self.MassFrac)) except: print('Wp=%s, Vp=%s, Winert=%s, dv=%s, GLOW=%s, mu=%s'%\ (self.WtPropellant, self.VolPropellant, self.WtInert, self.DeltaV, self.GLOW, self.MassFrac)) class ReferenceStagePair( ReferenceStage ): '''Scale reference stage pair to new propellant volume using getRhoVeh correlation''' def calc_rhoVeh(self, vol): vrat = (log10(vol)-log10(self.volCuIn2))/ (log10(self.volCuIn1)-log10(self.volCuIn2)) logRV = log10(self.rhoVeh2) + vrat*(log10(self.rhoVeh1)-log10(self.rhoVeh2)) rhoVeh = 10.0**logRV return rhoVeh def __init__(self, Name='N2H4 DACS', WtPayload=30.0, volCuIn1=463.58, WtInert1=18.1563, volCuIn2=192.23, WtInert2=15.28557): self.stage_desc = "Wpayload=%g lbm, Stage Pair from: %s"%(WtPayload, Name) self.WtPayload = WtPayload self.volCuIn1 = volCuIn1 self.WtInert1 = WtInert1 self.volCuIn2 = volCuIn2 self.WtInert2 = WtInert2 self.Name = Name self.rhoVeh1 = WtInert1 / volCuIn1 self.corrRhoStg1 = getRhoVeh( volCuIn1 ) self.rhoVeh2 = WtInert2 / volCuIn2 self.corrRhoStg2 = getRhoVeh( volCuIn2 ) self.corrFactor1 = self.rhoVeh1 / self.corrRhoStg1 self.corrFactor2 = self.rhoVeh2 / self.corrRhoStg2 self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass class ConstMassFracStage: """Assumes all propellants can achieve the same stage propellant mass fraction (A BAD ASSUMPTION)""" def __init__(self, mass_frac=0.8, WtPayload=1000.0): self.stage_desc = "Wpayload=%g lbm, Mass Fraction=%g (A BAD ASSUMPTION)"%(WtPayload, mass_frac) self.mass_frac = mass_frac self.WtPayload = WtPayload self.WtInert = None self.WtPropellant = None self.VolPropellant = None # cuin self.DeltaV = None self.GLOW = None # includes payload mass @property def MassFrac(self): try: mf = self.WtPropellant / (self.WtPropellant + self.WtInert) except: mf = 0.0 return mf def setGLOW(self, GLOW=5000.0, sg=1.0, Isp=300.0): self.GLOW = GLOW WstgIgn = self.GLOW - self.WtPayload self.WtPropellant = WstgIgn * self.mass_frac self.WtInert = WstgIgn - self.WtPropellant rho = sg * 0.0361273 self.VolPropellant = self.WtPropellant / rho Wbo = self.WtPayload + self.WtInert self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setWtInert(self, WtInert=1000.0, sg=1.0, Isp=300.0): self.WtInert = WtInert self.WtPropellant = self.mass_frac * WtInert / (1.0-self.mass_frac) rho = sg * 0.0361273 self.VolPropellant = self.WtPropellant / rho Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setWtPropellant(self, WtPropellant=1000.0, sg=1.0, Isp=300.0): self.WtPropellant = WtPropellant self.WtInert = WtPropellant * (1.0-self.mass_frac) / self.mass_frac rho = sg * 0.0361273 self.VolPropellant = self.WtPropellant / rho Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setVolPropellant(self, VolPropellant=10000.0, sg=1.0, Isp=300.0): self.VolPropellant = VolPropellant rho = sg * 0.0361273 self.WtPropellant = VolPropellant * rho self.WtInert = self.WtPropellant * (1.0-self.mass_frac) / self.mass_frac Wbo = self.WtPayload + self.WtInert self.GLOW = Wbo + self.WtPropellant self.DeltaV = gc * Isp * log( self.GLOW/Wbo ) def setDeltaV(self, DeltaV=2000.0, sg=1.0, Isp=300.0): self.DeltaV = DeltaV rho = sg * 0.0361273 gam = DeltaV / Isp / gc mu = self.mass_frac self.GLOW = self.WtPayload * mu / ( exp(-gam) - (1.0-mu) ) WstgIgn = self.GLOW - self.WtPayload self.WtPropellant = WstgIgn * mu self.WtInert = WstgIgn - self.WtPropellant self.VolPropellant = self.WtPropellant / rho def summ_print(self): try: print('mf=%g, Wp=%g, Vp=%g, Winert=%g, dv=%g, GLOW=%g, mu=%g'%\ (self.mass_frac, self.WtPropellant, self.VolPropellant, self.WtInert, self.DeltaV, self.GLOW, self.MassFrac)) except: print('mf=%g, Wp=%s, Vp=%s, Winert=%s, dv=%s, GLOW=%s, mu=%s'%\ (self.mass_frac, self.WtPropellant, self.VolPropellant, self.WtInert, self.DeltaV, self.GLOW, self.MassFrac)) if __name__=="__main__": if 1: #cmf = ConstMassFracStage() cmf = ReferenceStage() cmf.summ_print() cmf.setWtInert( WtInert=1000.0 ) else: cmf = ReferenceStagePair() cmf.summ_print() cmf.setWtInert( WtInert=15.28557 ) cmf.summ_print() wp = cmf.WtPropellant vol = cmf.VolPropellant dv = cmf.DeltaV glow = cmf.GLOW cmf.setWtPropellant( WtPropellant=wp ) cmf.summ_print() cmf.setVolPropellant( VolPropellant=vol ) cmf.summ_print() cmf.setDeltaV( DeltaV=dv) cmf.summ_print() cmf.setGLOW( GLOW=glow) cmf.summ_print()