o ffice n ational d’ É tudes et de r echerches a érospatiales
DESCRIPTION
15 - 17 september 2004 4th European Micro-UAV meeting Toulouse Micro engines for micro drones propulsion Joël Guidez, Clément Dumand, Olivier Dessornes, Yves Ribaud. O ffice N ational d’ É tudes et de R echerches A érospatiales. Outline of the presentation. 1/ Introduction : micro-systems - PowerPoint PPT PresentationTRANSCRIPT
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15 - 17 september 2004 4th European Micro-UAV meeting
Toulouse
Micro engines for micro drones propulsion
Joël Guidez, Clément Dumand, Olivier Dessornes, Yves Ribaud
Office National d’Études et de Recherches Aérospatiales
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Outline of the presentationOutline of the presentation
• 1/ Introduction : micro-systems
• 2/ Application to micro-drones
• 3/ Energetics micro-systems
• 4/ Micro-turbine
• 5/ Conclusion and perspectives
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1 / INTRODUCTION1 / INTRODUCTION
What is a MEMS (Micro Electro-Mechanical System) ?
• Miniaturization • Components : silicon, silicon-carbide• Applications :
SiC
Si
- sensors
- actuators
- energetics micro-systems
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What ’s MEMS ?What ’s MEMS ?
a sensitive element…
…frequently in silicon
Actuator(switch)
Accelerometer
electronics
packaging
puissance RFet transmission
capteur de température onvertisseur CAD
filtres digitaux
cea Leti
Gear
Miror
Pressure sensor
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But, it ’s also : an energetics micro-systemBut, it ’s also : an energetics micro-system
Micro-turbine
Micron-scale counterflowheat exchanger
20 mm
MIT
1 mm
TMIT(Tokyo)
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2 / APPLICATION TO MICRO-DRONES2 / APPLICATION TO MICRO-DRONES
• Mini and micro-drones
– fixed wing/rotating wing
– flapping wing
• Main specifications
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MicrobatCaltech
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Various MAV versions
Various MAV versions
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Microdrone : specificationsMicrodrone : specifications
• «Flying binocular» : system for collection of proximity information
• Dimension up to 15 cm : length and wingspan• Hovering, flight at 50 km/h • Autonomy : 20 mn to 1h• Power : 20 to 50 W• Mass 80 g• Data transmission in real time
Sensor Actuator Micro motorFuel tank
Electronic
Electrical/mechanical converter
(Video or other)
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3 / Energetics micro-systems : a lot of micro-systems and actors
3 / Energetics micro-systems : a lot of micro-systems and actors
• Micro-turbine :• MIT, Tokyo, Hoseï, Sendaï University, Tokyo Metropolitan Institute of Technology,
IHI, Onera, VKI, ERM, Leuwen University, National University of Singapore...
• Reciprocating free piston engine :• Georgia Tech, Berkeley, Birmingham University, KAIST (Corée)
• Wankel Micro-motor :• Berkeley, Birmingham University
• Thermoelectric micro-generator :• USC, Tohoku University, CEA, Onera, National University of Singapore
• Thermophotovoltaïc generator :• National University of Singapore, California State Polytechnic University ...
• Liquid rocket engine : • MIT, Uppsala University, QinetiQ, LAAS
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Reciprocating free-piston engineReciprocating free-piston engine
Exhaust valve
Combustion chamber
piston
Main shaft
Inlet valve
stator of electric generator
Electrical leads
cea Leti
Single variation
KAIST Korea
1 mm thick glassCombustion chamber 1 mm
Piston 2 x 2 mm
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Mini and micro-Wankel engineMini and micro-Wankel enginePresently 2.4 mm Si modelAim : Si fabrication, 1 mm x 300 µm10 to 100 mWSiC-coated Si
Berkeley
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13 mm3 W10000 rpm
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MIT Micro-turbine MIT Micro-turbine
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hydrogene
air inlet compressor
turbine.,..
exhaust
ONERA micro-turbine « upper combustor without premixed channel » ONERA micro-turbine « upper combustor without premixed channel »
Combustion chamber
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PP
P NN
Ceramic
Semi conductorP or N
MetallicConductor
Hot Junction
Cold junction
U
i
Thermoelectric microgeneratorThermoelectric microgenerator Thermoelectric wall
Ge-Si : 3 W/cm² 5%
THERMOELECTRIC GENERATORTHERMOELECTRIC GENERATOR
Combustion chamber
« Swiss roll »
USC
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Comparison between micro-systemsComparison between micro-systems
• Reciprocating free piston
engine
• rotating engine (Wankel)
• turbine engine
• thermoelectric system
• thermophotovoltaïque
system
Difficulties
Heat losses, friction, low frequency
Low rotating speed and low power
Complexity, high rotating speed, journal bearing
Connectic, catlytic combustion
To control this technique
Advantages
Well known
Well known
Good conversion mecanic/electric
Quasi static system
Relatively simple System quasi static
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4 / MICRO-TURBINE4 / MICRO-TURBINE
• Thermodynamic cycle
• Energetic balance
• Small scales problems...
• Combustion/ignition 4 mm
200 m
MIT
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Thermodynamic cycleThermodynamic cycle
S
T
th = 1 - 1/c -1/
c = 3 th=0.27
c = 4 th=0.33
c=0.7 et t=0.6,
thus cycle 0.11 à 0.14
Brayton-Joule cycle
C
C
Ch comb T
T
Ch comb.
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56 Wconvection 8 Wradiation 48 W
Thermal losses inexhaust gases( T = 1103 K )
430 W
Net Power
Work efficiency3.4 %
34 W Internal Heat Exchanges
External Heat Losses56 W
convection 8 Wradiation 48 W
Air flow0.4 g/s
Tair = 288 K
Tcompressor = 670 K
Tturbine= 840 K
Tchamber = 1600 K
Tstator = 930 K
Fuel : 46.6 g/h
6 W
19 W 33 W
16 W
12 W
23 W
3 W
34 W 82 W
28 W
9 W
51 W
MICRO-TURBINE : ENERGETIC BALANCE MICRO-TURBINE : ENERGETIC BALANCE
P comb = 503 W
Net power17 W
Global efficiency3,4 %
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COMPARISON OF PERFORMANCES COMPARISON OF PERFORMANCES
1
10
100
1000
10000
1 10 100 1000 10000 100000
BATTERIES
SUPER CAPACITORS
MICRO TURBINE
1,7%<global efficiency<10% Fuels : H2, CxHy
Specificenergy
Wh/kg
Specificpower
W/Kg
Autonomy : 1 h 20 mn
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Micro-scale combustorsSpecific problems
Micro-scale combustorsSpecific problems
• 1/ Low Reynolds number (< 1000)
• 2/ Residence time close to reaction time (Da around 1)
• 3/ Important heat losses (ratio S/V unfavourable)
• 4/ To improve ignition system (reusable)
• 5/ Quenching, self ignition in premixed channel
mixing
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Combustion :mixing, residence time, quenching
Combustion :mixing, residence time, quenching
Da = residence time/ reaction time
Da > 1 c 0,5 ms, thus Vmin = m’.c.r.T/P (4 mm)3
Quenching distance : d// = Pe.a/SL 0,2 mm (H2) 0,7 mm (Propane)
fuel
air
Mixing fuel/air
Mixing fresh gas/burned gas
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0D model results 0D model results
= s m
Residence time inthe micro-combustor
Heat losses Mixing ratio
PSR
PASR
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Y
Z
-0.0005 0 0.0005-0.0025
-0.002
-0.0015
-0.001
-0.0005
0
Y
Z
-0.0005 0 0.0005-0.0025
-0.002
-0.0015
-0.001
-0.0005
YZ
-0.0005 0 0.0005-0.0025
-0.002
-0.0015
-0.001
-0.0005
0
X
Z
0.002999940.003499940.003999940.004499940.004999940.00549994
-0.0024
-0.0022
-0.002
-0.0018
-0.0016
-0.0014
-0.0012
-0.001
-0.0008
-0.0006
-0.0004
-0.0002
0Temperature
240023002200210020001900180017001600150014001300120011001000900800700600500400300
Temperature240023002200210020001900180017001600150014001300120011001000900800700600500400300
ONERA ’s CFD codeONERA ’s CFD code
Development tool in order to select the best configurations of the micro-combustor
m’ = 0,1 g/sP = 3 barTp = 950 KModel : Ecklund (7 reactions)Equi.ratio = 0,6
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Set-up for combustion testsSet-up for combustion tests
Vessel cooled by nitrogen
Injection strut cooled,air and fuel inlet
Window for optical measurements(IR caméra, Raman...)
Micro-combustion chamber
Air and fuel inlet
ExhaustCombustion products
Vessel with micro-combustor Micro-combustor
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X
Z
0.002999940.003499940.003999940.004499940.004999940.00549994
-0.0024
-0.0022
-0.002
-0.0018
-0.0016
-0.0014
-0.0012
-0.001
-0.0008
-0.0006
-0.0004
25072369223120931955181716781540140212641126988850
5 / SUMMARY AND CONCLUSIONS5 / SUMMARY AND CONCLUSIONS
PhD work :> experimental study of mixing without combustion : 2004 and 2005> computations : 0D and 3D (for the design of the future combustors)
Combustion tests :> to carry out ignition tests (hot wire or film, electrical discharge)> to assess the flame stability (influence of heat losses, equivalence ratio, type of fuel (hydrogen or hydrocarbon) ...> to evaluate the combustor efficiency (heat balance, RAMAN scattering)Micro-systems : > to study new concepts of micro-turbines and specific combustors for direct electrical generation (catalytic combustion)...> thrust and journal bearings
Cooperations :> with other ONERA’s department for PLIF, RAMAN, thermoelectricity, igniter, flow simulation inside micro-compressor ...> CEA (LITEN), INPG/LEG, Silmach, NEDO (post doc.), TMIT ... Manufacturing, mehanical/electrical conversion
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Micro-manufacturingMicro-manufacturing
Centrifugal Compressor
Centripetal turbine
Si, Sic, Si3N4
MIT
5 / MICRO-TECHNOLOGIES 5 / MICRO-TECHNOLOGIES
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GAS THRUST BEARING AND JOURNAL BEARING
GAS THRUST BEARING AND JOURNAL BEARING
• Rotating speed about 1 million rpm
200 m
MIT