Transcript Orbital Payload Delivery Using Hydrogen and Hydrocarbon Fuelled Scramjet Engines
Orbital Payload Delivery Using Hydrogen and Hydrocarbon Fuelled Scramjet Engines
M. R. Tetlow and C.J. Doolan School on Mechanical Engineering The University of Adelaide
Overview
Current launch systems Scramjet background Mission profile and vehicle description Software operation Trajectory outputs Analysis of results Conclusions
Aim
Design a mission using a hydrocarbon powered (JetA) and a hydrogen powered scramjet stage to reach a 200km circular orbit Compare the mission profiles and performance of the two launch systems Compare the performance to current rocket powered systems
Current Launch Systems
Launch Vehicle ASLV M-3S11 Long March CZ1D Start-1 Payload mass (mass fraction) 150kg (0.36%) 780kg (1.26%) 720kg (0.9%) 360kg (0.6%) LEO orbit and inclination 400km at 43° 185km at 31° 200km at 28° 400km at 90° 1% at 200km is indicative of the performance of this class of vehicle [Isakowitz - 1995]
Scramjets
Supersonic combustion ramjet – Geometry dependent on operating conditions Hydrogen fuelled – High energy, low storage density – Operating range: Mach 5 to 15 – Isp ~ 3000s Hydrocarbon fuelled – Lower energy, high storage density – Operating range: Mach 5 to 10 – Isp ~1200s Minimum dynamic pressure ~10kPa
Waveriders
Waveriders
Blended wing vehicle with integrated propulsion system “Ride” the shock wave Aerodynamics are Mach No. dependent Fuel mass fractions – ε=0.58 for hydrogen fuelled vehicle – ε=0.7 for hydrocarbon fuelled vehicle – ε=0.9 for rockets
Quasi-1D Scramjet Propulsion Model
Flow From Inlet Displacement Thickness Growth Combustion Area Change Injector Ignition Delay Shear Stress Heat Transfer
Quasi-1D Scramjet Propulsion Model
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1 • Set of ODEs used to describe
scramjet propulsion.
• 2-step chemistry model. • Skin friction and wall heat
transfer included.
• H2 and Jet A fuel options. • Idealised hypersonic inlet
(with losses) used to supply combustor.
• Lawrence Livermore
ODEPACK Solver used for ODE solution.
240 220 200 180 160 140 120 100 80 60 40 0
Boyce et al (2000) Quasi-One-Dimensional Model
T4 Experiment
• Scramjet model validated against
shock tunnel data (T4, University of Queensland, Boyce et al., 2000).
• Parallel and diverging combustor
data used for validation study.
• Good agreement obtained using an
88% combustion efficiency.
• A conservative 50% combustion
efficiency was used for trajectory modelling (for combustor losses).
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Boyce et al (2000) Quasi-One-Dimensional Model
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Boyce, R.R., Paull, A., Stalker, R.J., Wendt, M., Chinzei, N. and Miyajima, H. Comparison of Supersonic Combustion Between Impulse and Vitiation-Heated Facilities,
Journal of Propulsion and Power
,
16(4)
, 2000, 709-717.
Common Design Parameters
GLOW 9300kg 2 stage solid rocket booster – Stage 1: 2420kg start mass, 1980kg propellant – Stage 2: 4880kg start mass, 4000kg propellant Cranked wing concept with aerodynamics taken from a NASA study Rocket powered upper stage with performance based on the H2 upper stage
Software Models
Simulation environment – 3DOF dynamics model, rotating spheroidal earth model, 4 th order gravitation model, MSISE 93 atmosphere model Target/constraints – Velocity stopping condition – Altitude and flight path angle targets for scramjet burn only Parameterised vertical acceleration profile
Common Mission Parameters
Booster 2 burn – 25s burn, Alt =19.6km, Vel =2411m/s Coast – 44.6s, Alt =25.3km, Vel =2000m/s ------------- Booster 1 burn – 10s burn, Alt =9.5km, Vel =550m/s Coast – 45.4s, Alt =15.9km, Vel =295m/s Orbital stage – Two burns, Alt =200km, Vel =7784m/s
Mission Profiles for Hydrogen Fuelled Vehicle
Hydrogen Case - Altitude Profile
60 55 50 45 40 35 30 25 20 15 10 5 0 0 50 100 150 200 250 300 350 400 450 500 550 600
Flight time [s]
Booster1 Coast Booster2 Coast Scram Coast
Hydrogen Case - Velocity Profile
5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 0 50 100 150 200 250 300 350 400 450 500 550 600
Flight time [s]
Booster1 Coast Booster2 Coast Scram Coast
Mission Profiles for Hydrocarbon Fuelled Vehicle
Hydrocarbon Case - Altitude Profile
45 40 35 30 25 20 15 10 5 0 0 50 Booster1 Coast Booster2 Coast Scram Coast 100 150 200
Flight time [s]
250 300 350
Hydrocarbon Case - Velocity Profile
45 40 35 30 25 20 15 10 5 0 0 50 Booster1 Coast Booster2 Coast Scram Coast 100 150 200
Flight time [s]
250 300 350
Payload Estimation
Mass and state at end of the scramjet burn Scramjet mass fractions – Hydrogen fuelled waverider ε propellant = 0.58
– Hydrocarbon fuelled waverider ε propellant = 0.7 Orbital stage – upper stage ε structure = 0.15
– ΔV requirement based on Hohmann transfer
Mass Breakdown
Hydrogen fuelled case Initial mass: 2000kg Fuel mass: 316kg Structure mass: 1000kg Orbital stage mass: 684kg Payload to 200km circular: 108.5kg
Payload mass fraction: 1.16% Hydrocarbon fuelled case Initial mass: 2000kg Fuel mass: 258.8kg Structure mass: 918.3kg
Orbital stage mass: 822.9kg
Payload to 200km circular: 36kg Payload mass fraction: 0.38%
Discussion
Payload mass fractions similar to rockets even though much higher Isp?
Considerably lower fuel mass fractions – i.e. more of stage mass is structure, compared to rockets Structure is more expensive than fuel.
– These systems need to be reusable to be financially viable
Discussion
Lighter scramjet stage for the hydrocarbon fuelled system Hydrogen fuelled vehicle considerably higher payload capability than hydrocarbon fuelled case – Longer duration burn at higher Isp for H2 case – Better packing efficiency does not help the hydrocarbon vehicle as a large aerodynamic area is needed to maintain lift at high altitude so the vehicle cannot be made smaller.
Conclusions
Similar payload mass fractions to rockets – Therefore need to be reusable Hydrocarbon fuelled case has lighter structure than hydrogen fuelled case – Better packing efficiency Better packing efficiency cannot be utilised due to aerodynamic requirements