Shuttle OMS

RocketIsp version 0.1.8 Friday, Dec 04, 2020 at 04:32PM
      N2O4/MMH
IspVac     = 313.668 sec
MRcore     = 1.83333
MRthruster = 1.65
Rt         = 2.90248 in
At         = 26.4661 in**2
Pc         = 125 psia
Fvac       = 6000 lbf
cham_freq  = 4341.35 Hz (2T=4489 Hz)
Nelements  = 277 (set by acoustics)
elemDens   = 3.91875 elem/in**2
DorfOx     = 0.0456 in
DorfFuel   = 0.0402 in
Plot
Plot
Plot
Geometry
Input
Parameter = Value Alt Value Description
cham_conv_deg = 30.00 deg half angle of conical convergent section
CR = 2.5 chamber contraction ratio (Ainj / Athroat)
eps = 55 nozzle area ratio (Aexit / Athroat)
LchamberInp = None in user input value of chamber length (will override all other entries)
LchmMin = 2.000 in 5.080 cm
0.167 ft
minimum chamber length (will override LchmOvrDt)
LchmOvrDt = 3.1 ratio of chamber length to throat diameter (Lcham / Dthrt)
LnozInp = None in user input nozzle length (will override pcentBell)
pcentBell = 80 nozzle percent bell (Lnoz / L_15deg_cone)
RchmConv = 1 radius of curvature at start of convergent section (Rconv / Rthrt)
RdwnThroat = 1 radius of curvature just downstream of throat (Rdownstream / Rthrt)
Rthrt = 2.902 in 7.372 cm
0.242 ft
throat radius
RupThroat = 1.5 radius of curvature just upstream of throat (Rupstream / Rthrt)
Output
Parameter = Value Alt Value Description
Ainj = 66.165 in**2 426.871 cm**2 area of injector
At = 26.466 in**2 170.749 cm**2 throat area
Dexit = 43.051 in 109.349 cm
3.588 ft
nozzle exit diameter
Dinj = 9.178 in 23.313 cm
0.765 ft
diameter of injector
Dthrt = 5.805 in 14.745 cm
0.484 ft
throat diameter
entrance_angle = 34.79 deg nozzle initial expansion angle
exit_angle = 7.70 deg nozzle exit angle
Lcham_conv = 4.866 in 12.359 cm
0.405 ft
length of convergent section of chamber
Lcham_cyl = 13.130 in 33.349 cm
1.094 ft
length of cylindrical section of chamber
Lnoz = 55.601 in 141.227 cm
4.633 ft
nozzle length
Ltotal = 73.597 in 186.936 cm
6.133 ft
nozzle + chamber length
Rinj = 4.589 in 11.657 cm
0.382 ft
radius of injector
Vcham = 1086.8 in**3 17810.1 cm**3 approximate chamber volume
N2O4/MMH Core Stream Tube
Input
Parameter = Value Alt Value Description
adjCstarODE = 1 multiplier on NASA CEA code value of cstar ODE (default is 1.0)
adjIspIdeal = 1 multiplier on NASA CEA code value of Isp ODE (default is 1.0)
CdThroat = 0.989745 Cd of throat (RocketThruster object may override)
(MLP fit)
fuelName = MMH name of fuel (e.g. MMH, LH2)
ignore_noz_sep = 0 flag to force nozzle flow separation to be ignored (USE WITH CAUTION)
MRcore = 1.83333 mixture ratio of core flow (ox flow rate / fuel flow rate)
oxName = N2O4 name of oxidizer (e.g. N2O4, LOX)
Pamb = 0.00 psia 0.00 MPa
0.00 atm
0.00 bar
ambient pressure (for example sea level is 14.7 psia)
Pc = 125.0 psia 0.86 MPa
8.51 atm
8.62 bar
chamber pressure
Output
Parameter = Value Alt Value Description
CfAmbDel = 1.81364 delivered ambient thrust coefficient
CfVacDel = 1.81364 delivered vacuum thrust coefficient
CfVacIdeal = 1.91514 ideal vacuum thrust coefficient
cstarERE = 5572.6 ft/s 1698.5 m/s delivered core cstar
cstarODE = 5693.3 ft/s 1735.3 m/s core ideal cstar
FvacBarrier = 675.4 lbf 3004.4 N vacuum thrust due to barrier stream tube
FvacCore = 5324.6 lbf 23684.9 N vacuum thrust due to core stream tube
FvacTotal = 6000.0 lbf 26689.3 N total vacuum thrust
gammaChm = 1.14074 core gas ratio of specific heats (Cp/Cv)
IspDel = 313.67 sec 3076.04 N-sec/kg
3.08 km/sec
<=== thruster delivered vacuum Isp ===>
IspDel_core = 319.25 sec 3130.81 N-sec/kg
3.13 km/sec
delivered Isp of core stream tube
IspODE = 338.89 sec 3323.37 N-sec/kg
3.32 km/sec
core one dimensional equilibrium Isp
IspODF = 318.56 sec 3123.99 N-sec/kg
3.12 km/sec
core frozen Isp
IspODK = 331.08 sec 3246.78 N-sec/kg
3.25 km/sec
core one dimensional kinetic Isp
MRthruster = 1.65 total thruster mixture ratio')
MWchm = 21.211 g/gmole core gas molecular weight
Pexit = 0.1606 psia 0.00 MPa
0.01 atm
0.01 bar
nozzle exit pressure
TcODE = 5612.0 degR 3117.8 degK
2844.6 degC
5152.3 degF
ideal core gas temperature
wdotFl = 7.218 lbm/s 3.274 kg/s total fuel flow rate
wdotOx = 11.910 lbm/s 5.402 kg/s total oxidizer flow rate
wdotTot = 19.128 lbm/s 8.677 kg/s total propellant flow rate (ox+fuel)
At Injector Face
Parameter = Value Alt Value Description
wdotFl_cInit = 6.496 lbm/s 2.947 kg/s initial core fuel flow rate (before any entrainment)
wdotFlFFC = 0.722 lbm/s 0.327 kg/s fuel film coolant flow rate injected at perimeter
wdotTot_cInit = 18.407 lbm/s 8.349 kg/s initial core total flow rate (before any entrainment)
After Entrainment
Parameter = Value Alt Value Description
wdotFl_b = 1.332 lbm/s 0.604 kg/s barrier fuel flow rate (FFC + entrained)
wdotFl_c = 5.886 lbm/s 2.670 kg/s final core fuel flow rate (injected - entrained)
wdotOx_b = 1.118 lbm/s 0.507 kg/s barrier oxidizer flow rate (all entrained)
wdotOx_c = 10.792 lbm/s 4.895 kg/s final core oxidizer flow rate (injected - entrained)
wdotTot_b = 2.450 lbm/s 1.111 kg/s total barrier propellant flow rate (includes entrained)
wdotTot_c = 16.678 lbm/s 7.565 kg/s total final core propellant flow rate (injected - entrained)
Efficiencies
Output
Parameter = Value Description
Isp = 0.92558 Overall Isp Efficiency
Noz = 0.96247 Nozzle Efficiency
ERE = 0.97880 Energy Release Efficiency of Chamber
FFC = 0.98251 (barrier calc) Fuel Film Cooling Efficiency of Chamber
Nozzle
Parameter = Value Description
Div = 0.99303 (simple fit eps=55, %bell=80) Divergence Efficiency of Nozzle
Kin = 0.97695 (MLP fit) Kinetic Efficiency of Nozzle
BL = 0.99208 (MLP fit) Boundary Layer Efficiency of Nozzle
Chamber
Parameter = Value Description
Mix = 0.99496 (mixAngle=1.42 deg) Inter-Element Mixing Efficiency of Injector
Em = 0.98537 (Rupe elemEm=0.8) Intra-Element Mixing Efficiency of Injector
Vap = 0.99836 (gen vaporized length) Vaporization Efficiency of Injector
Ignored Efficiencies
        TP: Two Phase Efficiency of Nozzle
        HL: Heat Loss Efficiency of Chamber
Barrier Stream Tube
Input
Parameter = Value Description
ko = 0.035 entrainment constant (typical value is 0.035, range from 0.03 to 0.06)
pcentFFC = 10 percent fuel film cooling ( FFC flowrate / total fuel flowrate)
Output
Parameter = Value Alt Value Description
cstarERE_b = 5063.9 ft/s 1543.5 m/s delivered cstar
cstarODE_b = 5173.6 ft/s 1576.9 m/s ideal equilibrium cstar
fracKin_b = 0 fraction of kinetic completion in barrier
IspDel_b = 275.65 sec 2703.21 N-sec/kg
2.70 km/sec
delivered vacuum barrier Isp
IspODE_b = 297.126 sec. ideal equilibrium barrier Isp
IspODF_b = 285.86 sec 2803.35 N-sec/kg
2.80 km/sec
ideal frozen barrier Isp
IspODK_b = 285.86 sec 2803.35 N-sec/kg
2.80 km/sec
vacuum kinetic Isp of barrier
MRbarrier = 0.839724 barrier mixture ratio
MRwall = 0.386862 mixture ratio at wall
TcODE_b = 3713.8 degR 2063.2 degK
1790.1 degC
3254.1 degF
average ideal ODE temperature of barrier gas
Twallgas = 2305.0 degR 1280.5 degK
1007.4 degC
1845.3 degF
temperature of gas at wall
WentrOvWcool = 2.39452 ratio of entrained flow rate to FFC flow rate
N2O4/MMH Injector
Assumptions
NOTE: Injector elements are designed by Initial Core Flow ONLY.
      Fuel Film Cooling orifices must be designed separately.
NOTE: number of elements set by acoustics
      Acoustic frequency set by 2T
Fuel Orifice Diameter Meets Stability Requirement of >= 40.1 mil
Chamber design frequency set by: acoustics to: 4341 Hz, (2T=4489 Hz)
Input
Parameter = Value Alt Value Description
desAcousMode = 2T driving acoustic mode of injector OR acoustic mode multiplier (setNelementsBy=="acoustics" and setAcousticFreqBy=="mode")
DorfMin = 0.0080 in 8.000 mil
0.203 mm
minimum orifice diameter (lower limit)
elemEm = 0.8 intra-element Rupe mixing factor (0.7 below ave, 0.8 ave, 0.9 above ave)
setAcousticFreqBy = mode flag indicating how to determine design frequency. (can be "mode" or "freq")
setNelementsBy = acoustics flag determines how to calculate number of elements ( "acoustics", "elem_density", "input")
Ox Properties
Parameter = Value Alt Value Description
CdOxOrf = 0.75 flow coefficient of oxidizer orifices
dropCorrOx = 0.33 oxidizer drop size multiplier (showerhead=3.0, like-doublet=1.0, vortex=0.5, unlike-doublet=0.33)
fdPinjOx = 0.25 fraction of Pc used as oxidizer injector pressure drop
LfanOvDorfOx = 20 fan length / oxidizer orifice diameter
OxOrfPerEl = 1 number of oxidizer orifices per element
Tox = 530.0 degR 294.4 degK
21.3 degC
70.3 degF
temperature of oxidizer
Fuel Properties
Parameter = Value Alt Value Description
CdFuelOrf = 0.75 flow coefficient of fuel orifices
dropCorrFuel = 0.33 fuel drop size multiplier (showerhead=3.0, like-doublet=1.0, vortex=0.5, unlike-doublet=0.33)
fdPinjFuel = 0.25 fraction of Pc used as fuel injector pressure drop
FuelOrfPerEl = 1 number of fuel orifices per element
LfanOvDorfFuel = 20 fan length / fuel orifice diameter
lolFuelElem = 0 flag for like-on-like fuel element (determines strouhal multiplier)
Tfuel = 530.0 degR 294.4 degK
21.3 degC
70.3 degF
temperature of fuel
Output
Parameter = Value Alt Value Description
des_freq = 4341.4 Hz chamber design acoustic frequency
DorfFlForHzLimit = 0.040 in 40.138 mil
1.019 mm
fuel orifice Diameter for frequency in Hewitt Correlation
elemDensCalc = 3.919 elem/in**2 0.607 elem/cm**2 element density on injector face
Nelements = 277 number of elements on injector face
NelemMakable = 6980 maximum number of makable elements giving correct flow rate (diam=DorfMin)
Ox Properties
Parameter = Value Alt Value Description
AfloOx = 0.453 in**2 2.919 cm**2 total flow area of oxidizer
dHvapOx = 177.52 BTU/lbm 98.69 cal/g
412.91 J/g
oxidizer heat of vaporization
DorfOx = 0.0456 in 45.607 mil
1.158 mm
oxidizer orifice diameter
dpOx = 31.25 psid 0.22 MPa
2.13 atm
2.15 bar
oxidizer injector pressure drop
MolWtOx = 92.011 g/gmole oxidizer molecular weight
NOxOrf = 277 number of oxidizer orifices on injector face
sgOx = 1.439 g/ml 0.052 lbm/inch**3
89.823 lbm/ft**3
oxidizer density
surfOx = 1.483e-04 lbf/in 2.598e-02 N/m
2.598e+01 mN/m
2.598e+01 dyne/cm
oxidizer surface tension
velOx_fps = 56.8 ft/s 17.3 m/s velocity of injected oxidizer
viscOx = 2.777e-04 poise 2.777e-02 cpoise
2.777e-05 Pa*s
6.718e-02 lbm/hr/ft
oxidizer viscosity
Fuel Properties
Parameter = Value Alt Value Description
AfloFuel = 0.351 in**2 2.264 cm**2 total flow area of fuel
dHvapFuel = 376.36 BTU/lbm 209.23 cal/g
875.41 J/g
fuel heat of vaporization
DorfFuel = 0.0402 in 40.161 mil
1.020 mm
fuel orifice diameter
dpFuel = 31.25 psid 0.22 MPa
2.13 atm
2.15 bar
fuel injector pressure drop
MolWtFuel = 46.072 g/gmole fuel molecular weight
NFuelOrf = 277 number of fuel orifices on injector face
sgFuel = 0.879 g/ml 0.032 lbm/inch**3
54.866 lbm/ft**3
fuel density
surfFuel = 1.951e-04 lbf/in 3.417e-02 N/m
3.417e+01 mN/m
3.417e+01 dyne/cm
fuel surface tension
velFuel_fps = 72.6 ft/s 22.1 m/s velocity of injected fuel
viscFuel = 5.534e-04 poise 5.534e-02 cpoise
5.534e-05 Pa*s
1.339e-01 lbm/hr/ft
fuel viscosity
Vaporization
Parameter = Value Alt Value Description
chamShapeFact = 0.6775 chamber shape factor
fracVapFuel = 0.9952 fraction of vaporized fuel
fracVapOx = 0.9998 fraction of vaporized oxidizer
genVapLenFuel = 51.81 Priem generalized vaporization length of fuel
genVapLenOx = 150.61 Priem generalized vaporization length of oxidizer
mrVap = 1.8418 vaporized mixture ratio
rDropFuel = 0.7562 mil 19.21 micron
0.02 mm
median fuel droplet radius
rDropOx = 0.5966 mil 15.15 micron
0.02 mm
median ox droplet radius
Combustion Stability
Parameter = Value Alt Value Description
cham sonicVel = 3532.3 ft/s 1076.7 m/s approximate gas sonic velocity in chamber
fdPinjFuelReqd = 0.137399 minimum required fuel dP/Pc
fdPinjOxReqd = 0.184498 minimum required oxidizer dP/Pc
tauFuel = 0.921372 ms fuel lag time (tau/tResid=0.609279)
tauOx = 1.33875 ms oxidizer lag time (tau/tResid=0.885277)
tResid = 1.5122 ms residual time in chamber
Acoustic Modes
Parameter = Value Alt Value Description
1L = 1177 Hz
80% of 1T = 2165 Hz no damping required here
1T = 2706 Hz
=====> DESIGN = 4341 Hz <== DESIGN IS HERE
2T = 4489 Hz
80% of 1R = 4506 Hz baffles-only work here
80% of 3T = 4940 Hz cavities-only work here
1R = 5632 Hz
3T = 6175 Hz baffles + cavities OR multi-tuned cavities
3T = 6175 Hz <== MAX FREQUENCY... KEEP Hz HERE OR BELOW
4T = 7816 Hz
1T1R = 7837 Hz
2T1R = 9857 Hz
2R = 10313 Hz
3T1R = 11782 Hz
1T2R = 12533 Hz