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N2O4/MMH IspVac = 313.744 sec MRcore = 1.72775 MRthruster = 1.65 Rt = 2.90696 in At = 26.5477 in**2 Pc = 125 psia Fvac = 6000 lbf |
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Shuttle OMS | |
| RocketIsp version 0.1.12 | Sunday, Jul 19, 2026 at 09:15AM |
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N2O4/MMH IspVac = 313.744 sec MRcore = 1.72775 MRthruster = 1.65 Rt = 2.90696 in At = 26.5477 in**2 Pc = 125 psia Fvac = 6000 lbf |
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| 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 = | 2.907 in |
7.384 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 = | 66.369 in**2 | 428.188 cm**2 | area of injector |
| At = | 26.548 in**2 | 171.275 cm**2 | throat area |
| Dexit = | 43.117 in |
109.518 cm 3.593 ft |
nozzle exit diameter |
| Dinj = | 9.193 in |
23.349 cm 0.766 ft |
diameter of injector |
| Dthrt = | 5.814 in |
14.767 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 = | 4.873 in |
12.378 cm 0.406 ft |
length of convergent section of chamber |
| Lcham_cyl = | 13.150 in |
33.401 cm 1.096 ft |
length of cylindrical section of chamber |
| Lnoz = | 55.687 in |
141.445 cm 4.641 ft |
nozzle length |
| Ltotal = | 73.710 in |
187.224 cm 6.143 ft |
nozzle + chamber length |
| Rinj = | 4.596 in |
11.675 cm 0.383 ft |
radius of injector |
| Vcham = | 1091.9 in**3 | 17892.5 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 = | 0.989747 |
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 = | 1.72775 | 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 = | 1.80807 | delivered ambient thrust coefficient | |
| CfVacDel = | 1.80807 | delivered vacuum thrust coefficient | |
| CfVacIdeal = | 1.89881 | ideal vacuum thrust coefficient | |
| cstarERE = | 5533.3 ft/s | 1686.5 m/s | delivered core cstar |
| cstarODE = | 5704.4 ft/s | 1738.7 m/s | core ideal cstar |
| FvacBarrier = | 1587.9 lbf | 7063.2 N | vacuum thrust due to barrier stream tube |
| FvacCore = | 4412.1 lbf | 19626.1 N | vacuum thrust due to core stream tube |
| FvacTotal = | 6000.0 lbf | 26689.3 N | total vacuum thrust |
| gammaChm = | 1.14763 | core gas ratio of specific heats (Cp/Cv) | |
| IspDel = | 313.74 sec |
3076.77 N-sec/kg 3.08 km/sec |
<=== thruster delivered vacuum Isp ===> |
| IspDel_core = | 315.31 sec |
3092.09 N-sec/kg 3.09 km/sec |
delivered Isp of core stream tube |
| IspODE = | 336.66 sec |
3301.48 N-sec/kg 3.30 km/sec |
core one dimensional equilibrium Isp |
| IspODF = | 319.28 sec |
3131.08 N-sec/kg 3.13 km/sec |
core frozen Isp |
| IspODK = | 329.92 sec |
3235.39 N-sec/kg 3.24 km/sec |
core one dimensional kinetic Isp |
| MRthruster = | 1.65 | total thruster mixture ratio') | |
| MWchm = | 20.765 g/gmole | core gas molecular weight | |
| Pexit = | 0.1544 psia |
0.00 MPa 0.01 atm 0.01 bar |
nozzle exit pressure |
| TcODE = | 5545.6 degR |
3080.9 degK 2807.7 degC 5085.9 degF |
ideal core gas temperature |
| wdotFl = | 7.217 lbm/s | 3.273 kg/s | total fuel flow rate |
| wdotOx = | 11.907 lbm/s | 5.401 kg/s | total oxidizer flow rate |
| wdotTot = | 19.124 lbm/s | 8.674 kg/s | total propellant flow rate (ox+fuel) |
| At Injector Face | |||
| Parameter = | Value | Alt Value | Description |
| wdotFl_cInit = | 6.892 lbm/s | 3.126 kg/s | initial core fuel flow rate (before any entrainment) |
| wdotFlFFC = | 0.325 lbm/s | 0.147 kg/s | fuel film coolant flow rate injected at perimeter |
| wdotTot_cInit = | 18.799 lbm/s | 8.527 kg/s | initial core total flow rate (before any entrainment) |
| After Entrainment | |||
| Parameter = | Value | Alt Value | Description |
| wdotFl_b = | 2.087 lbm/s | 0.946 kg/s | barrier fuel flow rate (FFC + entrained) |
| wdotFl_c = | 5.130 lbm/s | 2.327 kg/s | final core fuel flow rate (injected - entrained) |
| wdotOx_b = | 3.044 lbm/s | 1.381 kg/s | barrier oxidizer flow rate (all entrained) |
| wdotOx_c = | 8.863 lbm/s | 4.020 kg/s | final core oxidizer flow rate (injected - entrained) |
| wdotTot_b = | 5.131 lbm/s | 2.327 kg/s | total barrier propellant flow rate (includes entrained) |
| wdotTot_c = | 13.993 lbm/s | 6.347 kg/s | total final core propellant flow rate (injected - entrained) |
| Efficiencies |
|---|
| Output | ||
|---|---|---|
| Parameter = | Value | Description |
| Isp = | 0.93194 | Overall Isp Efficiency |
| Noz = | 0.96554 | Nozzle Efficiency |
| ERE = | 0.97000 | (constant) Energy Release Efficiency of Chamber |
| FFC = | 0.99505 | (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 = | 0.97998 | (MLP fit) Kinetic Efficiency of Nozzle |
| BL = | 0.99218 | (MLP fit) Boundary Layer Efficiency of Nozzle |
| Ignored Efficiencies |
|---|
| TP: Two Phase Efficiency of Nozzle |
| 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 = | 4.5 | percent fuel film cooling ( FFC flowrate / total fuel flowrate) |
| Output | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| cstarERE_b = | 5505.1 ft/s | 1678.0 m/s | delivered cstar |
| cstarODE_b = | 5675.4 ft/s | 1729.9 m/s | ideal equilibrium cstar |
| fracEntr = | 0.25565 | fraction of core flow entrained into barrier | |
| fracKin_b = | 0.54338 | fraction of kinetic completion in barrier | |
| IspDel_b = | 309.48 sec |
3034.99 N-sec/kg 3.03 km/sec |
delivered vacuum barrier Isp |
| IspODE_b = | 328.745 | sec. ideal equilibrium barrier Isp | |
| IspODF_b = | 317.97 sec |
3118.24 N-sec/kg 3.12 km/sec |
ideal frozen barrier Isp |
| IspODK_b = | 323.83 sec |
3175.65 N-sec/kg 3.18 km/sec |
vacuum kinetic Isp of barrier |
| MRbarrier = | 1.45886 | barrier mixture ratio at throat | |
| MRwall = | 1.19172 | mixture ratio at throat wall | |
| TcODE_b = | 5250.9 degR |
2917.2 degK 2644.0 degC 4791.2 degF |
average ideal ODE temperature of barrier gas |
| Twallgas = | 4744.5 degR |
2635.8 degK 2362.7 degC 4284.8 degF |
temperature of gas at throat wall (cooler upstream) |
| WentrOvWcool = | 14.7993 | ratio of entrained flow rate to FFC flow rate | |