Transcript Micro engines for micro drones propulsion 15 - 17 september 2004 Toulouse

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
Outline of the presentation
• 1/ Introduction : micro-systems
• 2/ Application to micro-drones
• 3/ Energetics micro-systems
• 4/ Micro-turbine
• 5/ Conclusion and perspectives
2
1 / INTRODUCTION
What is a MEMS (Micro Electro-Mechanical System) ?
• Miniaturization
• Components : silicon, silicon-carbide
• Applications :
SiC
- sensors
- actuators
- energetics micro-systems
Si
3
What ’s MEMS ?
Accelerometer
a sensitive element…
Actuator
(switch)
…frequently in silicon
Gear
packaging
Miror
electronics
puissance RF
et transmission
capteur de température
cea Leti
filtres digitaux
onvertisseur CAD
Pressure
sensor
4
4
But, it ’s also : an energetics micro-system
1 mm
TMIT
(Tokyo)
Micron-scale counterflow
heat exchanger
20 mm
MIT
Micro-turbine
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2 / APPLICATION TO MICRO-DRONES
• Mini and micro-drones
– fixed wing/rotating wing
– flapping wing
• Main specifications
Microbat
Caltech
6
Various MAV
versions
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Microdrone : 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
(Video or other)
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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 engine
Exhaust valve
Main shaft
stator of electric generator
piston
Inlet valve
Combustion chamber
Electrical leads
Single variation
KAIST Korea
1 mm thick glass
Combustion chamber 1 mm
Piston 2 x 2 mm
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cea Leti
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Mini and micro-Wankel engine
13 mm
3W
10000 rpm
Presently 2.4 mm Si model
Aim : Si fabrication, 1 mm x 300 µm
10 to 100 mW
SiC-coated Si
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11
Berkeley
MIT Micro-turbine
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ONERA micro-turbine « upper combustor without premixed channel »
hydrogene
Combustion
chamber
exhaust
turbine
.
,
.
.
air inlet
compressor
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THERMOELECTRIC GENERATOR
Thermoelectric microgenerator
Thermoelectric wall
Combustion chamber
Hot Junction
Ceramic
P
N
Metallic
Conductor
P
N
P
Semi conductor
P or N
i
U
Cold junction
Ge-Si : 3 W/cm²
h  5%
« Swiss roll »
USC
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Comparison between micro-systems
Difficulties
Advantages
• Reciprocating free piston
engine
Heat losses, friction, low
frequency
Well known
• rotating engine (Wankel)
Low rotating speed and low
power
Well known
• turbine engine
Complexity, high rotating
speed, journal bearing
Good conversion
mecanic/electric
• thermoelectric system
Connectic, catlytic
combustion
Quasi static system
To control this technique
Relatively simple
System quasi static
• thermophotovoltaïque
system
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4 / MICRO-TURBINE
• Thermodynamic cycle
• Energetic balance
• Small scales problems...
• Combustion/ignition
4 mm
MIT
200 mm
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Thermodynamic cycle
C
Brayton-Joule cycle
hth = 1 - 1/tc (g-1/g)
Ch comb.
T
T
Ch comb
tc = 3 
h
tc = 4 
h
th=0.27
th=0.33
T
hc=0.7 et ht=0.6,
C
S
thus h cycle  0.11 à 0.14
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56 W
convection 8 W
radiation 48 W
MICRO-TURBINE : ENERGETIC BALANCE
Tair = 288 K
51 W
Air flow
0.4 g/s
23 W
Fuel : 46.6 g/h
19 W
33 W
3 W
T compressor = 670 K
T stator = 930 K
34 W
T chamber = 1600 K
P comb = 503 W
82 W
T turbine= 840 K
28 W
16 W
9W
Net
Netpower
Power
17 W
Work efficiency
Global
efficiency
3.4 %
3,4 %
6W
34 W
12 W
Internal Heat Exchanges
56 W
convection 8 W
radiation 48 W
External Heat Losses
Thermal losses in
exhaust gases
( T = 1103 K )
43018 W
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COMPARISON OF PERFORMANCES
10000
Specific
energy
Autonomy : 1 h
20 mn
Wh/kg
1000
MICRO TURBINE
1,7%<global efficiency<10%
Fuels : H2, CxHy
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BATTERIES
10
Specific
SUPER CAPACITORS
power
W/Kg
1
1
10
100
1000
10000
100000
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Micro-scale combustors
Specific problems
• 1/ Low Reynolds number (< 1000)
• 2/ Residence time close to reaction time (Da around 1) mixing
• 3/ Important heat losses (ratio S/V unfavourable)
• 4/ To improve ignition system (reusable)
• 5/ Quenching, self ignition in premixed channel
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Combustion :
mixing, residence time, quenching
fuel
Mixing fuel/air
air
Mixing fresh gas/burned gas
Da = residence time/ reaction time
Da > 1  tc  0,5 ms, thus Vmin = m’.tc.r.T/P  (4 mm)3
Quenching distance : d// = Pe.a/SL  0,2 mm (H2)  0,7 mm (Propane)
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0D model results
PASR
PSR
Residence time in
the micro-combustor
Heat losses
Mixing ratio
=
ts/tm
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-0.0005
-0.0005
-0.0005
-0.0005
-0.0005
-0.0005
-0.0005
-0.0005
-0.0005
-0.001
-0.001
-0.001
-0.001
-0.001
-0.001
-0.001
-0.001
-0.001
-0.0015
-0.0015
-0.0015
-0.0015
-0.0015
-0.0015
-0.0015
-0.0015
-0.0015
-0.002
-0.002
-0.002
-0.002
-0.002
-0.002
m’ = 0,1 g/s
-0.002
-0.002
-0.002
P = 3 bar
Tp = 950 K
-0.0025
-0.0025
-0.0005
-0.0005
-0.0005
Model : Ecklund (7 reactions) -0.0025
Equi.ratio = 0,6
0 00
Y YY
0.0005
0.0005
0.0005
-0.0025
-0.0025
-0.0025
-0.0005
-0.0005
-0.0005
Z
Z
0 00
Z
Z
Development tool in
order to select the best
configurations of the
micro-combustor
0 00
Z
Z
Z
ONERA ’s CFD code
0 00
Y YY
0.0005
0.0005
0.0005
-0.0025
-0.0025
-0.0025
-0.0005
-0.0005
0 0
YY
0.0005
0.0005
0
Temperature
2400
2300
2200
2100
2000
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
-0.0002
-0.0004
-0.0006
-0.0008
-0.001
Z
-0.0012
-0.0014
-0.0016
-0.0018
-0.002
-0.0022
-0.0024
0.002999940.003499940.003999940.004499940.004999940.00549994
Temperature
2400
2300
2200
2100
2000
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
X
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Set-up for combustion tests
Air and fuel inlet
Injection strut cooled,
air and fuel inlet
Micro-combustion chamber
Window for optical measurements
(IR caméra, Raman...)
Vessel
cooled by nitrogen
Vessel with micro-combustor
Exhaust
Combustion products
Micro-combustor
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5 / SUMMARY AND CONCLUSIONS
-0.0004
-0.0006
-0.0008
2507
2369
2231
2093
1955
1817
1678
1540
1402
1264
1126
988
850
PhD work :
> experimental study of mixing without combustion : 2004 and 2005
> computations : 0D and 3D (for the design of the future combustors)
-0.001
Z
-0.0012
-0.0014
-0.0016
-0.0018
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
-0.002
-0.0022
-0.0024
0.00549994 0.00499994 0.00449994 0.00399994 0.00349994 0.00299994
X
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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5 / MICRO-TECHNOLOGIES
Micro-manufacturing
Centrifugal Compressor
Si, Sic, Si3N4
Centripetal turbine
MIT
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GAS THRUST BEARING
AND JOURNAL BEARING
•
Rotating speed about 1 million rpm
200 mm
MIT
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