8. 250 hp engine for unmanned helicopter
Post on 03-Apr-2018
232 Views
Preview:
TRANSCRIPT
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
1/52
250 HP engine for unmanned helicopterwith reduced infrared signature
Advisor - Dr. Boris Glezer
Jessica Yana (aerothermodynamic/ stress specialist)
Yonatan Lobovikov (designer)
Akiva Sharma (combustor/heat exchanger specialist)
GAS TURBINE DESIGN PROJECT
http://en.wikipedia.org/wiki/File:RQ-8A_Fire_Scout.jpg -
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
2/52
Preview
1. Project goals and objectives
2. Component selection
3. Thermodynamic cycle
4. Compressor geometry
5. Turbine geometry
6. Cooling
7. Stress analysis
8. Combustion chamber & heat exchanger
9. Design
10. Competiting products
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
3/52
Project Goals and Objectives
Overall mission : fly autonomously to the battlefield, provide fighting
troops with ammunition and evacuate wounded to rear hospital
Output power 250HP
Light weight
Simple design
Compact
Low cost
Reduced heat signature
Dusty enironment (low altitude mission)
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
4/52
Components Selection Compressor
Centrifugal Compressor:
Compact design
Lower weight
Lower cost (size and weight lower)
Higher efficiency
2 stages (Improved efficiency)
1 shaft (more simple - cheaper)
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
5/52
Components Selection Turbine
Axial Turbine:
suitable for high temperatures
Better efficiency
First two stages drive the compressor
Third (last) stage Provide output power (via gear box)
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
6/52
Components Selection Hot Section
Spiral Recuperator
Compact
Lightweight
Combustor
Annular combustor
Simple design
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
7/52
Thermodynamic Cycle - Scheme
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
8/52
Thermodynamic Cycle - Inputs
Flight conditions
Standard atmosphere
Mach 0.2
Additional parameters selected (hystorical data)
Pressure ratio 9
TIT 1400K
Thermal efficiency 38%
Fuel to air ratio (converged value) 0.015
Cooling air
Stage 1 nozzle & blade 2.3%
Stage 2 blisk1%
Stage 1 blisk2%
Losses & Efficiency
PRESSURE LOSSES
Air intake 3%
Exhaust 5%
Combustion chamber 3.5%
Heat exchanger 5%
EFFICIENCY
Compressor 0.75
Turbine 0.85
HEX effectiveness 0.85
Mechanical losses 1%
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
9/52
Thermodynamic Cycle - Outputs
0.75kg/s
0.23kg / kW-hr
airm
SFC
St. T(K) PR
Compressor
1 290 2.5
2 400 3.6
Turbine
1 1400 1.44
2 1195 2.5
3 1036 6.85
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
10/52
Compressor Parameters
First
stage
Second
stage
Mass flow rate [kg/s] 0.75 0.75
Pressure ratio 3.5 2.6
Inlet temperature [K] 290K 400K
efficiency 0.85 0.85
Rotation speed [rpm] 63,000 63,000
Total diameter [mm] 174 144
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
11/52
Compressor Geometry
First
stage
Second
stage
Total diameter [mm] 174 144
Eye root diameter [mm] 40 40
Eye tip diameter [mm] 154.8 125
Root incidence angle [deg] 27.3 27.3
Tip incidence angle [deg] 7.6 9.4
Impeller channel depth [mm] 23 7
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
12/52
Turbine Parameters
1st
stage
2nd
stage
Power
turbine
Mass flow rate
[kg/s]0.76 0.76 0.76
Pressure ratio 1.44 2.5 6.85
Inlet temperature
[K]1400 1191 1036
efficiency 0.85 0.85 0.85
Rotation speed
[rpm]63 000 63 000 40 000
Total diameter
[mm]183.1 190.4 245
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
13/52
Turbine Geometry
1st stage 2nd stage Power turbine
St. Rot. St. Rot. St. Rot.
Total diameter [mm] 183.1 183.1 187 193.8 232 244.5
No. of blades 24 33 26 37 18 32
Mean blade height [mm] 8.1 8.1 9.3 9.6 20 22.2
Blade chord [mm] 16 6.2 17 7.4 40 18
L.E diameter [mm] 0.8 0.8 0.9 0.9 2.0 2.3
root [deg] 10 27 10 21 10.5 54
tip [deg] 10 25 9.5 19 9.5 46
root [deg] 39 48.5 43 48.5 46 51.5
tip [deg] 36 46 40.5 45.5 43 43
Pitch to chord ratio chart
2 /b mN R s
Height to chord ratio:
Stator ~ 2
Rotor ~ 1.3
umber of blades
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
14/52
Turbine Flow Path
Untwisted blades
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
15/52
CoolingSwirl cooling method
Metal temperature limit =1250K=950C
1st stage (nozzle and blade) had to be cooled
Cooling air
Stage 1 nozzle & blade 2.3%
Stage 2 blisk1%
Stage 1 blisk2%
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
16/52
Life Time Prediction - Uncooled Blades
Blade temperature
Stage 2 1076K
age 3 877K
Centrifugal stress (max)
Stage 2 185Mpa
Stage 3 350Mpa
Life time estimation
Critic section at the root
Material Waspalloy
Stage 2: 10 000 hours (SF=1.3)
Stage 3: 20 000 hours (SF=1.3)
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
17/52
Cooled Blades - Stress
Centrifugal & bending stress
Life time fixed to 10 000 hours
Larson miller chart
0
50
100
150
200
250
300
350
1 2 3 4 5 6 7 8 9 10 11
Stress[MP
a]
Blade section
Blade Section Stress
Safety Factor
Bending Stress
Centrifugal Stress
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
18/52
Cooled Stage Temperatures
0
1
2
3
4
5
6
7
8
9
1100 1300 1500
BladeHeight[cm
]
Temperature [K]
Temperature Profile
Metal
Temperature
1D
Gas temperature pattern factor 1.1
Safety margins 30%.
3D
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
19/52
Airfoil external heat transfer coefficient 12.4 kW/m2K
Cooling effectiveness 28%
cooling flow parameter 0.8
Coolant mass flow rate 2.3%
Cooling
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
20/52
0
0.02
0.04
0.06
0.08
0.1
0.12
300 500 700 900 1100 1300
Diskradius[m]
Temperature [K]
Blisk metal temperature
stage1
stage 2
stage 3
15
35
55
75
95
0.02 0.04 0.06 0.08 0.1
Stress[MPa]
Radius [m]
Blisk radial stress
stage 1
stage 2
stage 3
Blisk Life Time Prediction
50
100
150
200
250
300
0.02 0.04 0.06 0.08 0.1
Stress[Mpa]
Radius [m]
Blisk tangential stress
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
21/52
Blisk Life Time Prediction
Critical sction towards the tip
Stage 1 blisk: 42 000 hours (SF=1.5)
Stage 2 blisk: 16 000 hours (SF=1.5)
Stage 3 blisk: 1 560 000 hours (SF=1.5)
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
22/52
Combustor Design Considerations
Performance Objectives:
High combustion efficiency ~ 99%
Low overall system total pressure loss ~
3%
Stable combustion at all operating
conditions
Minimum size, weight, cost.
Effective hot part cooling
Required TIT met
Proper temperature distribution at the
exit
Low emissions
Relightability
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
23/52
Design Parameters
34.0)05.0exp(1
ref
L
D
L
q
P
L
LPF
6110.130075.1
3
3
bK
Tair
VoleP
m
016.1* ,*
pr
combustoroutpcombustorpturbi ne
h
TCTITCf
=f/ fstoi= 0.255
%5.3
3
34
P
P
SFC = Fuel Flow / Power Produced
= 0.23 kg/kW-hr
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
24/52
Dimensions
Combustor Cross sectional area= 0.0055 m2
Radius Liner = 0.003 m
Length of Primary Zone = 0.1048 m
Length of Dilution Zone = 0.0698 m
Total Combustor Length = 0.1746 m
Volume = 0.0061 m3
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
25/52
Air Distribution
:
Primary Zone Air ~ 24%
Dome Air ~ 5 %
Dilution ~ 28%
Nozzle Air ~ 2 %
Liner Cooling ~ 32%
Turbine Cooling ~ 9%
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
26/52
Recirculation Zone
6943.2tan)/(1
)/(1
3
22
3
swhub
swhubn
DD
DDS
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
27/52
Materials & CoolingCombustor Liner - Silicon Nitride
High temperature strength
High oxidation resistance
Low cycle fatigue strength
High cycle fatigue strength
High corrosion resistance
Combustor Housing - Inco 909
Elevated high temperature strength
Low cycle fatigue strength
Thermal Barrier Coating - SN-220
Low emmisivity
Low thermal conductivity
Oxidation resistant
Chemically inert
Resistant to thermal shock
Resistant to wear/erosion
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
28/52
Heat Exchanger
m26.04
)*(6.2 min U
CNTU
A
)1
1)(log
1
1(
rC
rC
NTU
1
1 1
i o
U
h h
z
i H
kh Nu
H
1.25 0.40.023 Re PrH HNu
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
29/52
Heat Exchanger - Pressure Drop
f LP gh
2
2L L Vh f
H g
If it is known that for turbulent flow: f = 0.316/Re1/4
For hot gas, pressure drop of 0.245 atm is obtained.
For cold air the pressure loss is 0.003 atm.
hL = frictional head loss [m]
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
30/52
Engine Design
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
31/52
Shafts
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
32/52
1st Stage Compressor
d
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
33/52
2nd Stage Compressor
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
34/52
Combustor
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
35/52
Stage 1
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
36/52
Stage 1
Turbine
b
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
37/52
Stage 1 Turbine
d b
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
38/52
Second & Power Turbines
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
39/52
H E h
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
40/52
Heat Exchanger
H E h
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
41/52
Heat Exchanger
H E h
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
42/52
Heat Exchanger
F l S
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
43/52
Fuel System
F l S
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
44/52
Fuel System
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
45/52
O ll Fl P th
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
46/52
Overall Flow Path
Cl
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
47/52
Clearances
Seals
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
48/52
Seals
M ti
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
49/52
Mountings
Competing products
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
50/52
Competing productsPower plant of Northrop Grumman UAV helicopter : Roll Royce 250
RR300 designed for light helicopter and general aviation aircraft Optimized in the 240-300
HP power range
Competing products
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
51/52
Competing products
-
7/29/2019 8. 250 HP Engine for Unmanned Helicopter
52/52
top related