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 |
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Geometry |
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Input | |||
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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 | |||
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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 |
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Input | |||
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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) |
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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 | |||
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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 |
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Output | ||
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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 |
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TP: Two Phase Efficiency of Nozzle |
HL: Heat Loss Efficiency of Chamber |
Barrier Stream Tube |
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Input | ||
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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 | |||
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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 |
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Assumptions |
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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 | |||
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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 | |||
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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 |