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Beijing Institute of Control Engineering
The Research of High Energy and Green Monopropellant
Propulsion Module for Cubesats
Xuhui Liu, Yan Shen, Jun Yao , Yusong Yu, Zhang [email protected]
Spaceworks: Up to 2020，about hundreds of small satellites will be launched every
year.
传统皮卫星
硅卫星（MCMSAT)
单芯片卫星（Chi pSat )
单板卫星（PCBSat )
The development of Small Satellites
• Deep space exploration has been carried out for more than 50 years.• The success rate is only 50%.• Cubesats are based on the commercial shelf technology• Low cost, light weight, simple structure, customized design
Requirements of Deep space exploration
• Micro and nano satellite technology has made a number of important breakthrough
• Power supply, communication, processing, attitude and orbit control and space control capabilities.
Requirements of Deep Space Exploration
• Cubesats planetary exploration is difficult by its own propulsion• As the second load following the mother satellite• Pilot task • Looking for the landing point, and the observation of asteroids or
celestial gravitational and magnetic field• Orbit transfer, reaching to the projected orbit
Requirements of Deep Space Exploration
6
Propellant Tank
Pressurant Tank
Tooling Hardware
• Proof pressure testing• Expulsion testing• Hot-fire Testing
The Development of Micro propulsion module
7
MOOG
The Development of Micro propulsion module
8
BUSEK
The Development of Micro propulsion module
• In 2016，0.2N hydrazine micro propulsion system is flied in PN-1/2
•
Traditional Propulsion System
贮箱（1L）
压力传感器
液加注阀
气加注阀
自锁阀
0. 2N推力器 0. 2N推力器 0. 2N推力器 0. 2N推力器
• Propellant:500g• Total impluse:931Ns
• Weight:1.65kg
BICE
Direction X
Y
O PropulsionModule
A1
A2
A3
A4
Direction Z
• Orbit deployment• Error cancellation• Orbit maintenance control
Ø High ImpulseØ Larger Thrust
Requirement analysis
The module integrates 4 0.2N thrusters, 2 filling valve, 1 tanks, 1 pressure sensor, 4 safety valves. The main structure of the module is realized by 3D printing technology.
• Propellant: ADN • Specific impulse: 210s (ADN). • The weight of the propulsion system
(including propellant): less than 1.3kg; • Power consumption: less than 4W; • Working voltage: 5V; • Total impluse: 800Ns (ADN) • Mounting board envelope size ：98mm *
98mm * 98mm.
Micro Monopropellant propulsion module Technology
u Traditional Propulsion System• Toxic and not suitable for long-term storage• High pressure gas to pressurizeu Based on solid cool gas generator, ADN based propellant Ø The module is stored at atmospheric pressure.
After the satellite into the orbit, the solid cool gas generator will be drived to produce nitrogen. At the same time, the use of solid cool gas form, can ensure that the whole system to maintain a high pressure box work, can improve the performance of the whole system.
Ø Higher tank pressure(2.0MPa~1.5MPa Vs 2.0MPa~0.5MPa)Ø Higher IspØ ADN based monopropellant is no-toxic.
a mixture of three compoents, by the oxidation of hydroxyl ammonium nitrate component or ammonium dinitramide, fuel and water.
Module characteristics and working principle
Module characteristics and working principle
u1U micro propulsion module of the total impluse can reach to 800NsuThe thrust range can reach to 200mN~1NuThe mininum impulse is 10-2N • s
Module characteristics and working principle
2MPa
4MPa
15
Diameter：Φ18mm
High：16mm
Weight：15g±1g
Gas：N2
Gas purity：≥96%
Gas mass：1.2g
Solid Cool Gas Generator Introduction
16
The generator works by activating the initiator when receives the ignition signal; and then the
energy formed by the initiator fires the booster; after being triggered by the booster, the
generant begins to yield gas by sustainably and steady combustion, then the gas is filtered by
the filter, and vented through the nozzles.
Solid Cool Gas Generator Introduction
17
2 2 29CO (g) 33H O(g) 20N (g) 8Cu(s)= + + +6 4 3 3 2 29CH N O (s) 2[Cu(NO ) 3Cu(OH) ](s)+ ´
3 5 2 2 22CH N (s) 7CuO(s) 7Cu(s) 3H O(g) 2CO (g) 5N (g)+ = + + +
2 4 4 2 3 2 29C H N O (s) 4[Cu(NO ) 3Cu(OH) ](s)+ ×
（1）
（2）
（3）
2 2 218CO (g) 30H O(g) 22N (g) 16Cu(s)+ + +
3 23NaN Na N2
= +（4） √
Solid Cool Gas Generator Design
18
To avoid large amount of liquid sodium spraying out, metal oxide is introduced in gas
generant. The most commonly used oxidant is iron oxide (Fe2O3). According to the
reaction equation, iron and sodium oxide (Na2O) in solid state would be generated in the
reaction, which both have higher melting point than that of sodium. Thus the residue of
iron and sodium oxide could be more easily filtered than sodium and hold in the gas
generator.
3 2 3 2 26NaN (s) Fe O (s) 9N (g) 2Fe(s) 3Na O(s)+ = + +
Solid Cool Gas Generator Design
19
Cold gas generator adopts the electric ignition mode. For nano-satellite application, ignition
requires lower power consumption . Thus ignition design for cold gas generator uses step by
step amplification to ignite gas generant finally.
Bridge wire resistance： 7.5Ω-10Ω
Firing current： DC 150 mA
Safe current： DC 30 mA
Solid Cool Gas Generator Ignition Design
20
The cool gas inflator is tested in a 500ml tank, and when it works the gas generated by the
inflator is exhausted in the tank. The numerical simulation of the cold gas inflator is based
on following hypotheses:
1.The propellant follows the cigarette burning law and the geometric burning law.
2.The gas in the combustion chamber and the tank is fully mixed instantly.
3.The burning of the ignition charge is considered as a source item, and the law of it is
confirmed by experiments.
4.The influences of the solid residue are ignored.
5.The components of the gas from the combustion of the propellant are invariable, and the
thermodynamic parameters of the gas are constants.
Numerical Simulation
21
The solution of the equations is based on four-order Runge-Kutta method, and the
thermodynamic parameters are calculated by Real program. The Figure shows the
comparison of the simulation results and experimental results.
Numerical Simulation
The physical and chemical processes in the ADN thruster are complexincluding capillary multiphase flow, liquid jet breakup, multiphase flow inporous medium, heat and mass transfer in catalyst bed, catalytic reactionand combustion, etc.
Fig. 1 Schematic of the complex work processes in ADN thruster
Catalyst and combustion processes in ADN thruster
ADN liquid properties
Density at 20℃ (kg/m3) 1290Cp at 20℃ (J/kg k) 2350
Viscosityat 20℃ (mPas) 4.60Latent heat (kj/kg) 1425.7Boiling point (K) 400
Specific heat capacity at 20℃(kj/(K kg) ) 2.35
Catalyst particle properties
Dp(m) 1.18e-3∅ Porosity 0.5Cp(J/kg k) 871
Catalytic particles Ir/Al2O3
Tab. 1 ADN and catalyst particle properties
The propellant consisting of ternary mixtures with ADN/water/CH3OH injects into the thruster. The physical properties of ADN liquid are listed in Tab. 1. Catalyst bed is filled with porous catalyst particles.
Catalyst and combustion processes in ADN thruster
Capillary multiphase flow in hot millimeter-scale tube is a complex problem. Inorder to simplify this problem, the Euler-Euler framework coupling mixturemethod and the Reynolds averaged Navier-Stokes (RANS) equations which aretime-averaged equations of motion for fluid flow are used. In present study, theevaporation and condensation is modeled by Lee Model.
Based on the following temperature regimes, the mass transfer can be described as follows:
The evaporation-condensation flux F based on the kinetic theory for a flat interface:
Where, subscript v denotes vapor phase, αv is vapor volume fraction, ρv is vapordensity, Vv is vapor phase velocity, ṁlv is the rates of mass transfer due toevaporation, kg/s/m3.
C1 is a relaxation time coefficient, which can be obtain by following formulation.
Mathematical models of capillary multiphase flow in propellant tube
Initial boundary conditions
Inlet mass flux(kg/s) 1e-4Inject pressure(MPa) 1
Injection temperature(K) 300Pre-heating temperature(K) 470
mass fraction of ADN 0.63mass fraction of CH3OH 0.11
mass fraction of H2O 0.26
Due to the complex structures and the random placement of particles in thecatalytic bed, particles have serious influences on the flow and the heat transfer,and the catalytic particles have been dealt into the spherical particles in a virtualporous medium within the calculation. The finite chemical rate chemical reactionmodel is used to study turbulence chemistry interaction. The thruster uses vacuumboundary condition.
Tab. 2 Initial boundary conditions
InletOutlet
Wall
Mathematical models of flow/reaction processesin ADN thruster
Physicalprocess NumericalmodelTurbulent flow k-ε realizable model
Propellant evaporation Multi-component Particle evaporation model
Heat transfer between fluid-solid phase Two temperature porous medium model
Pressure drop through porous bed Ergun model
Catalytic reaction/combustionFinite chemical rate model
(Simplified reaction model: 20-reaction and 22-species)
Tab. 3 Mathematical models
Tab. 4 The reaction mechanism
Mathematical models of flow/reaction processesin ADN thruster
(1) Capillary multiphase flow in propellant tubeFluid/solid coupling heat transfer simulation method is carried out. Thetube internal diameter is 0.14 mm, outer diameter is 0.6mm. The mass flowrate of propellant (ADN/H2O/CH3OH mixture) is 0.1 g/s. The ambientpressure is equal to experimental results measured by pressure sensorlocated in combustion chamber.
Pressure/MPa 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Tsat(℃,CH3OH)
64 83 95 104 112 118 123 128 133
Tsat(℃,H2O) 100 120 134 144 152 159 165 171 175
Tab. 5 Saturation temperature at different pressure
Pressure/MPa 0.014 0.025 0.056 0.12Tsat(℃,ADN) 22.6 39.2 60.1 80.1
Results and discussion
(1) Capillary multiphase flow in propellant tubeThe fluid-solid-heat coupling method is used to simulate present process.Calculation strategy:
- Use coupled solver with low Courant numbers.- Lower the explicit relaxation factors for pressure and momentum to 0.6- Ensure reverse flow volume fraction properly defined at outletboundaries.
Solid domainFluid domain(tube)
Mass flow inlet
Pressure outlet
Fig. 2 Fluid/solid domain and boundary conditions
Millimeter-scale tube
Heat flux due to combustion
Results and discussion
(1) Capillary multiphase flow in propellant tubeThe fluid-solid-heat coupling method is used to simulate present process.
Fig. 4 Vapor distribution at 50s (left: wall surface, right: axial plane)
Vapor bubbles Vapor bubbles
Fig. 3 Temperature distribution at 50s (left: wall surface, right: axial plane)
Heat boundary
Results and discussion
(1) Capillary multiphase flow in propellant tubeADN and water vapor are formed near the wall boundary. There is no vaporat the central region. It are more likely to block near the region of tube outletwith smaller diameter.
Fig. 6 H2O vapor distribution at 50s (left: wall surface, right: axial plane)
Fig. 5 ADN vapor distribution at 50s (left: wall surface, right: axial plane)
High risk block area
Results and discussion
(2) Combustion processes in ADN thrusterThe predicted pressure in thruster is 0.35 MPa~0.36 MPa, which is agreewith the experimental data well. Due to relative low heat release ofcatalytic reactions and the effect of heat capacity of the catalytic particles,catalyst bed-temperature maintains low value.
ADN is decomposed in the catalytic bed. One of the main oxidant NO2 isformed at the upstream region of the catalyst bed.
Fig. 7 Computational results of ADN thruster
Results and discussion
(2) Combustion processes in ADN thruster• N2O, the unstable intermediate, is distributed near the inlet region.• NO is formed at the upstream region of the catalyst bed, and is consumed
due to reduction reaction at the downstream region of the catalyst bed.• CO mainly occurs at the upstream region of the catalyst bed.
Fig. 8 Computational results of ADN thruster
Results and discussion
200mN ADN Based Thruster Firing Test
Firing Test
ØThe roughness of the combustion pressure is 1%~7%
ØThe steady ignition time is more than 600s
ØThe preheating ignition number : ≥100
ØPulse cycles: ≥10000
ØThe specific impulse was about 205s.
Ø Solid cool gas generator to pressurizeØ Propellant based on ADN Ø Plug and playØ Additive manufacturingØ Micro no-toxic monopropellant thruster(Simulation Test)Ø Total impulse is more than 800Ns
Conclusion
求 实 / 求 是 / 创 新 / 超 越
THANKS!
