100 lbf Engine | |
RocketIsp version 0.1.10 | Sunday, Dec 13, 2020 at 10:35AM |
N2O4/N2H4 IspVac = 317.326 sec MRcore = 1.26 MRthruster = 1.071 Rt = 0.360216 in At = 0.40764 in**2 Pc = 137 psia Fvac = 100 lbf cham_freq = 17954.9 Hz(82% 1T) Nelements = 596 (set by acoustics) elemDens = 75.8851 elem/in**2 DorfOx = 0.0097 in DorfFuel = 0.0095 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 = | 75 | nozzle area ratio (Aexit / Athroat) | |
LchamberInp = | None in | user input value of chamber length (will override all other entries) | |
LchmMin = | 1.000 in |
2.540 cm 0.083 ft |
minimum chamber length (will override LchmOvrDt) |
LchmOvrDt = | 3 | 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 = | 0.360 in |
0.915 cm 0.030 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 = | 1.019 in**2 | 6.575 cm**2 | area of injector |
At = | 0.408 in**2 | 2.630 cm**2 | throat area |
Dexit = | 6.239 in |
15.847 cm 0.520 ft |
nozzle exit diameter |
Dinj = | 1.139 in |
2.893 cm 0.095 ft |
diameter of injector |
Dthrt = | 0.720 in |
1.830 cm 0.060 ft |
throat diameter |
entrance_angle = | 35.70 deg | nozzle initial expansion angle | |
exit_angle = | 7.63 deg | nozzle exit angle | |
Lcham_conv = | 0.604 in |
1.534 cm 0.050 ft |
length of convergent section of chamber |
Lcham_cyl = | 1.557 in |
3.956 cm 0.130 ft |
length of cylindrical section of chamber |
Lnoz = | 8.238 in |
20.926 cm 0.687 ft |
nozzle length |
Ltotal = | 10.400 in |
26.415 cm 0.867 ft |
nozzle + chamber length |
Rinj = | 0.570 in |
1.447 cm 0.047 ft |
radius of injector |
Vcham = | 2.0 in**3 | 32.8 cm**3 | approximate chamber volume |
N2O4/N2H4 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 = | 0.985313 |
Cd of throat (RocketThruster object may override) (MLP fit) |
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fuelName = | N2H4 | name of fuel (e.g. MMH, LH2) | |
ignore_noz_sep = | 0 | flag to force nozzle flow separation to be ignored (USE WITH CAUTION) | |
MRcore = | 1.26 | 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 = | 137.0 psia |
0.94 MPa 9.32 atm 9.45 bar |
chamber pressure |
Output | |||
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Parameter = | Value | Alt Value | Description |
CfAmbDel = | 1.79062 | delivered ambient thrust coefficient | |
CfVacDel = | 1.79062 | delivered vacuum thrust coefficient | |
CfVacIdeal = | 1.938 | ideal vacuum thrust coefficient | |
cstarERE = | 5641.4 ft/s | 1719.5 m/s | delivered core cstar |
cstarODE = | 5787.6 ft/s | 1764.1 m/s | core ideal cstar |
FvacBarrier = | 26.6 lbf | 118.2 N | vacuum thrust due to barrier stream tube |
FvacCore = | 73.4 lbf | 326.6 N | vacuum thrust due to core stream tube |
FvacTotal = | 100.0 lbf | 444.8 N | total vacuum thrust |
gammaChm = | 1.13912 | core gas ratio of specific heats (Cp/Cv) | |
IspDel = | 317.33 sec |
3111.90 N-sec/kg 3.11 km/sec |
<=== thruster delivered vacuum Isp ===> |
IspDel_core = | 320.51 sec |
3143.18 N-sec/kg 3.14 km/sec |
delivered Isp of core stream tube |
IspODE = | 348.61 sec |
3418.74 N-sec/kg 3.42 km/sec |
core one dimensional equilibrium Isp |
IspODF = | 327.19 sec |
3208.59 N-sec/kg 3.21 km/sec |
core frozen Isp |
IspODK = | 335.20 sec |
3287.20 N-sec/kg 3.29 km/sec |
core one dimensional kinetic Isp |
MRthruster = | 1.071 | total thruster mixture ratio') | |
MWchm = | 20.222 g/gmole | core gas molecular weight | |
Pexit = | 0.1116 psia |
0.00 MPa 0.01 atm 0.01 bar |
nozzle exit pressure |
TcODE = | 5521.3 degR |
3067.4 degK 2794.2 degC 5061.6 degF |
ideal core gas temperature |
wdotFl = | 0.152 lbm/s | 0.069 kg/s | total fuel flow rate |
wdotOx = | 0.163 lbm/s | 0.074 kg/s | total oxidizer flow rate |
wdotTot = | 0.315 lbm/s | 0.143 kg/s | total propellant flow rate (ox+fuel) |
At Injector Face | |||
Parameter = | Value | Alt Value | Description |
wdotFl_cInit = | 0.129 lbm/s | 0.059 kg/s | initial core fuel flow rate (before any entrainment) |
wdotFlFFC = | 0.023 lbm/s | 0.010 kg/s | fuel film coolant flow rate injected at perimeter |
wdotTot_cInit = | 0.292 lbm/s | 0.133 kg/s | initial core total flow rate (before any entrainment) |
After Entrainment | |||
Parameter = | Value | Alt Value | Description |
wdotFl_b = | 0.051 lbm/s | 0.023 kg/s | barrier fuel flow rate (FFC + entrained) |
wdotFl_c = | 0.101 lbm/s | 0.046 kg/s | final core fuel flow rate (injected - entrained) |
wdotOx_b = | 0.035 lbm/s | 0.016 kg/s | barrier oxidizer flow rate (all entrained) |
wdotOx_c = | 0.128 lbm/s | 0.058 kg/s | final core oxidizer flow rate (injected - entrained) |
wdotTot_b = | 0.086 lbm/s | 0.039 kg/s | total barrier propellant flow rate (includes entrained) |
wdotTot_c = | 0.229 lbm/s | 0.104 kg/s | total final core propellant flow rate (injected - entrained) |
Efficiencies |
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Output | ||
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Parameter = | Value | Description |
Isp = | 0.91025 | Overall Isp Efficiency |
Noz = | 0.94322 | Nozzle Efficiency |
ERE = | 0.97475 | Energy Release Efficiency of Chamber |
FFC = | 0.99005 | (barrier calc) Fuel Film Cooling Efficiency of Chamber |
Nozzle | ||
Parameter = | Value | Description |
Div = | 0.99334 | (simple fit eps=75, %bell=80) Divergence Efficiency of Nozzle |
Kin = | 0.96153 | (MLP fit) Kinetic Efficiency of Nozzle |
BL = | 0.98753 | (MLP fit) Boundary Layer Efficiency of Nozzle |
Chamber | ||
Parameter = | Value | Description |
Mix = | 0.99823 | (mixAngle=0.84 deg) Inter-Element Mixing Efficiency of Injector |
Em = | 0.98478 | (Rupe elemEm=0.8) Intra-Element Mixing Efficiency of Injector |
Vap = | 0.99157 | (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 = | 15 | percent fuel film cooling ( FFC flowrate / total fuel flowrate) |
Output | |||
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Parameter = | Value | Alt Value | Description |
cstarERE_b = | 5555.6 ft/s | 1693.4 m/s | delivered cstar |
cstarODE_b = | 5699.5 ft/s | 1737.2 m/s | ideal equilibrium cstar |
fracKin_b = | 0.27895 | fraction of kinetic completion in barrier | |
IspDel_b = | 308.83 sec |
3028.60 N-sec/kg 3.03 km/sec |
delivered vacuum barrier Isp |
IspODE_b = | 325.104 | sec. ideal equilibrium barrier Isp | |
IspODF_b = | 322.16 sec |
3159.32 N-sec/kg 3.16 km/sec |
ideal frozen barrier Isp |
IspODK_b = | 322.98 sec |
3167.37 N-sec/kg 3.17 km/sec |
vacuum kinetic Isp of barrier |
MRbarrier = | 0.693743 | barrier mixture ratio | |
MRwall = | 0.362649 | mixture ratio at wall | |
TcODE_b = | 4653.7 degR |
2585.4 degK 2312.2 degC 4194.0 degF |
average ideal ODE temperature of barrier gas |
Twallgas = | 3460.6 degR |
1922.5 degK 1649.4 degC 3000.9 degF |
temperature of gas at wall |
WentrOvWcool = | 2.76881 | ratio of entrained flow rate to FFC flow rate |
N2O4/N2H4 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 3T |
Fuel Orifice Diameter Meets Stability Requirement of >= 9.5 mil |
Chamber design frequency set by: acoustics to: 17955 Hz,(82% 1T) |
Input | |||
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Parameter = | Value | Alt Value | Description |
desAcousMode = | 3T | 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 = | 17954.9 Hz | chamber design acoustic frequency | |
DorfFlForHzLimit = | 0.009 in |
9.484 mil 0.241 mm |
fuel orifice Diameter for frequency in Hewitt Correlation |
elemDensCalc = | 75.885 elem/in**2 | 11.762 elem/cm**2 | element density on injector face |
Nelements = | 596 | number of elements on injector face | |
NelemMakable = | 838 | maximum number of makable elements giving correct flow rate (diam=DorfMin) | |
Ox Properties | |||
Parameter = | Value | Alt Value | Description |
AfloOx = | 0.044 in**2 | 0.287 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 = | 0.0097 in |
9.745 mil 0.248 mm |
oxidizer orifice diameter |
dpOx = | 34.25 psid |
0.24 MPa 2.33 atm 2.36 bar |
oxidizer injector pressure drop |
MolWtOx = | 92.011 g/gmole | oxidizer molecular weight | |
NOxOrf = | 596 | number of oxidizer orifices on injector face | |
sgOx = | 1.439 g/ml |
0.052 lbm/inch**3 89.825 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 = | 59.4 ft/s | 18.1 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 = | 0.042 in**2 | 0.272 cm**2 | total flow area of fuel |
dHvapFuel = | 582.19 BTU/lbm |
323.66 cal/g 1354.18 J/g |
fuel heat of vaporization |
DorfFuel = | 0.0095 in |
9.487 mil 0.241 mm |
fuel orifice diameter |
dpFuel = | 34.25 psid |
0.24 MPa 2.33 atm 2.36 bar |
fuel injector pressure drop |
MolWtFuel = | 32.045 g/gmole | fuel molecular weight | |
NFuelOrf = | 596 | number of fuel orifices on injector face | |
sgFuel = | 1.009 g/ml |
0.036 lbm/inch**3 63.003 lbm/ft**3 |
fuel density |
surfFuel = | 3.846e-04 lbf/in |
6.736e-02 N/m 6.736e+01 mN/m 6.736e+01 dyne/cm |
fuel surface tension |
velFuel_fps = | 71.0 ft/s | 21.6 m/s | velocity of injected fuel |
viscFuel = | 6.764e-04 poise |
6.764e-02 cpoise 6.764e-05 Pa*s 1.636e-01 lbm/hr/ft |
fuel viscosity |
Vaporization | |||
Parameter = | Value | Alt Value | Description |
chamShapeFact = | 0.6775 | chamber shape factor | |
fracVapFuel = | 0.9838 | fraction of vaporized fuel | |
fracVapOx = | 0.9999 | fraction of vaporized oxidizer | |
genVapLenFuel = | 32.12 | Priem generalized vaporization length of fuel | |
genVapLenOx = | 174.24 | Priem generalized vaporization length of oxidizer | |
mrVap = | 1.2806 | vaporized mixture ratio | |
rDropFuel = | 0.2150 mil |
5.46 micron 0.01 mm |
median fuel droplet radius |
rDropOx = | 0.1275 mil |
3.24 micron 0.00 mm |
median ox droplet radius |
Combustion Stability | |||
Parameter = | Value | Alt Value | Description |
cham sonicVel = | 3539.1 ft/s | 1078.7 m/s | approximate gas sonic velocity in chamber |
fdPinjFuelReqd = | 0.107705 | minimum required fuel dP/Pc | |
fdPinjOxReqd = | 0.128634 | minimum required oxidizer dP/Pc | |
tauFuel = | 0.22278 ms | fuel lag time (tau/tResid=0.459329) | |
tauOx = | 0.273257 ms | oxidizer lag time (tau/tResid=0.563402) | |
tResid = | 0.4850 ms | residual time in chamber | |
Acoustic Modes | |||
Parameter = | Value | Alt Value | Description |
1L = | 9825 Hz | ||
80% of 1T = | 17481 Hz | no damping required here | |
=====> DESIGN = | 17954 Hz | <== DESIGN IS HERE | |
1T = | 21851 Hz | ||
2T = | 36247 Hz | ||
80% of 1R = | 36378 Hz | baffles-only work here | |
80% of 3T = | 39886 Hz | cavities-only work here | |
1R = | 45473 Hz | ||
3T = | 49858 Hz | baffles + cavities OR multi-tuned cavities | |
3T = | 49858 Hz | <== MAX FREQUENCY... KEEP Hz HERE OR BELOW | |
4T = | 63106 Hz | ||
1T1R = | 63270 Hz | ||
2T1R = | 79584 Hz | ||
2R = | 83258 Hz | ||
3T1R = | 95120 Hz | ||
1T2R = | 101187 Hz |