presentation acme engineering- two stage turbo shaft engine- pratt and whittney
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Gas Turbine DesignProject Presentation
ACME Aerospace Inc.
“History will be kind to me, for I intend to write it.”- Winston Churchill
Project Plan- Milestones
Overall Cycle Analysis for gas turbine configuration.
High Pressure Turbine.
Mean line Analysis Loss Calculations Smith’s Chart- The Sanity Check ! Rotor Geometry – Hub/ Tip Analysis
Design Selection - Engineering Analysis
Economic feasibility study – Tradeoffs !
OFF- Design Analysis
Business Case !
Aero + Stress
Costing…
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Cycle Analysis
1
4
5
6
7
s
T
32
∆ 𝑷𝒃
(8 % + 1 %) Bleed + ACC(3.3 % + 1.65 %) Vane + Disk(2.1%) Disk
Cooling Details
Mass Flow Rates = 46.94 = 41.73 = 5.216 = 0.4698 = 0.095
FAN
BOO
ST STAG
E
HPC H
PT LPT
C/C
1 2 3 6 7
4 5 8
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FAN
BOO
ST STAG
E
HPC H
PT LPT
C/C
1 2 3 6 7
4 5 8
Cycle Analysis
Mass Flow Rates = 46.94 = 41.73 = 5.216 = 0.4698 = 0.095
(8 % + 1 %) Bleed + ACC(3.3 % + 1.65 %) Vane + Disk(2.1%) Disk
Cooling Details
Stage
Component Pressure (bar)
Temperature(K)
0-1 Diffuser 0.268 244.431-2 Fan 0.3819 2732-3 Boost Comp. 1.072 382.513-4 HPC 3.216 549.424-5 C/C 3.158 1148.045-6 HPT 1.610 9716-7 LPT 0.241 645.27-8 Hot Nozzle 0.175 593.212-8 Cold Nozzle 0.165 207.2
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High Pressure Turbine- Mean Line Analysis Parameter
sState 1 State 2 State 3
Temp (K) 1149.347 1038.2178 939.6054
P (bar) 3.15603268 2.359808269 1.434861637
C (m/s) 82.7328 446.5382 269.7755
Cw (m/s) 17.0223 485.6564 58.2745
Ca (m/s) 81.4523 180.1132 265.2863
Area (m2) 0.0606 0.0364 0.0364
Vw(m/s) - 150.3764 393.5545
β (°) - 39.8559 56.0173
V (m/s) - 234.6355 474.6177
MR - 0.3779 0.7928
TOR (k) - 1031.5134 1037.1271
POR (bar) - 2.22138546 2.09704923
M 0.1257 0.7093 0.45
α (°) -10 66.2609 10.5
R (%) 0.48
Y 0.0596 0.0446
ζ 0.1142 0.0761
η% 92.5%
Design Presumptions
Mach No
Swirl Angle
Inlet 0.125 -10
Exit 0.45 10.5
Vane BladeAspect Ratio 0.7 1.45
Zwiefel Coeff 0.8 0.95TE Thickness
(inches)0.045 0.025
Reaction- 0.48Efficiency – 0.87 = 4.5 x Work- 182.369 KJ/kg= 4.84174 = 5.015 = 5.1298
1
2
3
Inlet to nozzle vanesInlet to rotor
Exit of rotor
1
23
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Loss Calculations/ Smith Chart
92.5
Smith ChartLosses Calculation
Nozzle Section Aerodynamic Loss Distribution
Kp Ks KteBlade Section Aerodynamic Loss
Distribution
Kp Ks Kte
58
65
2411
2715
Note: Tip Leakage losses are assumed 1 %.
- Trailing Edge
- Secondary
- Profile
Efficiency After Losses- 88.59 %
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Stage Geometry- Hub Tip Analysis
-0.98
Metal Angles
-3
-4.3
64.04
67.26
70.65
48
50
57
Stagger AnglesVariation: 9
HUB
TIP
HUB
TIP
Vane Geometry- Hub Mean Tip
SI Units Hub Mean Tip
Stagger ɣ(°) 57 50 48
Height h 0.0540
Chord C 0.0772
0.0143 0.0137 0.0132
Axial chord 0.0420 0.0496 0.0516
N 18 18 18
Pitch (S) 0.0400 0.0471 0 .0589
Zwiefel (Ψ) - 0.8 -
Throat Ov 0.01347 0.0228 0.0258
°
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Rotor Geometry- Hub Tip AnalysisBlade Geometry- Hub Mean Tip
-4.3
-19.44
8.7
39
63.16
60.29
57.07
Metal Angles
Stagger AnglesVariation: 32.5
52.5
38.0
20.0
HUB
TIP
TIP
HUB
SI Units Hub Mean Tip
Stagger ɣ(°) 20 38 52.5
Height h 0.0427
Chord C 0.0294
0.00575 0.0055 0.0048
Axial chord 0.0276 0.0232 0.0179
N 35 35 35
Pitch (S) 0.0206 0.0244 0 .0282
Zwiefel (Ψ) - 0.95 -
Throat Ov 0.0104 0.0121 0.0127
°
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Assembled Rotor GeometryParameters Qty/ Measurements
No of Vanes 18No of Blades 35Pitch- 0.0244Axial 0.0232Throat 0.0121Blade height 0.0427Vane height 0.0540Mean radius ( Vane) 0.1418Mean radius (Blade) 0.1361
4.5 x
Blade
Vane
Design Nozzle Vanes
Rotor Blades
Design 1 (88.59%)
18 35
Design 2 (87.99%)
28 53
Design 3 (88.36%)
21 41
Design 4 (88.04%)
28 58
Design 5 (88.55%)
21 38
Lowest number of vanes and blade
Blade geometry details calculated for Design 1 ( η = 88.59 %)
View- A
View- B
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Aerodynamic vs Stress Analysis
Aerodynamic Analysis
High AN^2 leads to greater value of “blade speed” which results in higher pitch and less number of blades
Lesser number of blades reduce Profile , TE and tip leakage losses. On contrary Secondary losses increase.
Efficiency increases.
30 35 40 45 50 55 6087.687.787.887.9
8888.188.288.388.488.588.688.7
Number of Blades vs Efficiency %
Number of Blades
Efficie
ncy
2.00E+10 3.00E+10 4.00E+10 5.00E+1087.687.787.887.9
8888.188.288.388.488.588.688.7
AN^2 vs Efficiency %
AN ^2
Efficie
ncy
20000000000 30000000000 40000000000 500000000000
10
20
30
40
50
60
70AN ^2 vs # of Blades
AN ^2
No o
f Bla
des
Decrease in # of blades with increasing
D= 4.5 x
Increase in efficiency with
Decrease in efficiency with increasing # of blades
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Stress Analysis
High AN^2 leads to greater value of “blade speed” which results in higher “Centrifugal Tensile Stress”
More stretched blade , results in lesser effect of “Gas Bending Stress”.
High efficiency corresponds to low gas bending but high centrifugal stresses.
Aerodynamic vs Stress Analysis
2.00E+102.50E+103.00E+103.50E+104.00E+104.50E+105.00E+100
0.2
0.4
0.6
0.8
1
1.2
1.4Gas Bending Stress vs AN^2
AN ^2
Gas B
endi
ng S
tress
(MPa
)
Reduction in Gas bending stress with increasing 𝐴𝑁^2
2.00E+10 3.00E+10 4.00E+10 5.00E+10050
100150200250300350400450 Centrifugal Tensile Stress vs AN ^2
AN ^2
Cent
rifug
al S
tress
(MPa
) Linear relationship b/w Centrifugal stress & 𝐴𝑁^2
87.9 88 88.1 88.2 88.3 88.4 88.5 88.6 88.70
50100150200250300350400450
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Centrifugal / Gas Bending Stress vs
Efficiency
Centrifugal Tensile Stress (Mpa)Efficiency
Cent
rifug
al T
ensil
e (M
Pa)
Gas B
endi
ng (M
Pa)
Increasing Centrifugal stress
Decreasing Bending Stress
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Cost Analysis
Design-1 (88.59%)
Design-2 (87.9918 %)
Design-3 (88.36 %)
Design-4 (88.045 %)
Design-5 (88.554 %)
050000
100000150000200000250000300000350000400000450000500000
Comparision of Engine Design for Total Relative Cost vs Efficiency
5000 Hrs 4000 Hrs 7000 HrsMaterial With Efficiency
Tota
l Rel
ativ
e Co
sts
$
Analysis
FORMULATotal Cost = Fuel Cost + Total Blade Cost + Overall Maint. Cost
Material Z is coming with lowest total cost with different number of blade configurations (or designs)
Analysis
FORMULATotal Relative Cost = Overall Maint. Cost + Total Blades Cost + Relative Fuel Cost
Considering Design 1 as our baseline Relative Fuel Cost = 0 $
For Design 1, Total Relative Cost for 7000 hrs. is minimum.
X = 5000 hrs.Y = 4000 hrs.Z = 7000 hrs.
X Y z X Y z X Y z X Y z X Y z35 38 41 53 58
107501080010850109001095011000110501110011150
Overall Cost v/s Blade Count
Number of blades with material
Tota
l Cos
t x 1
000
$
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87.9 88 88.1 88.2 88.3 88.4 88.5 88.6 88.70
10
20
30
40
50
60
70
10840
10860
10880
10900
10920
10940
10960
10980Number of Blades/Total Cost vs Efficiency
Efficiency %
Num
ber o
f Bla
des
Tota
l Cos
t x 1
000
$
Eff % vs Total Cost
Eff % vs Number of Blades
88.59 % (35)
88.55 % (38)
88.36 % (41)
88.04 % (58)
87.99 % (53)
106.6106.7106.8106.9
107107.1107.2107.3107.4107.5107.6107.7
533
534
535
536
537
538
539
Efficiency v/s Fuel Consumption/ Fuel Cost
Efficiency (Number of blades)
Fuel
Con
sum
ptio
n (G
allo
ns/H
r)
Fuel
Con
sum
ptio
n co
st ($
/Hr)
Analysis With decreasing efficiency fuel consumption and
cost increases. Lesser efficiency corresponds to more number of
blades hence more losses and greater quantity of fuel is required to fly an aircraft.
Reduction in Power to Weight Ratio with more # of blades
Cost Analysis
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Design Selection – Aero + Stress +Cost
87.9 88 88.1 88.2 88.3 88.4 88.5 88.6 88.710840
10860
10880
10900
10920
10940
10960
10980
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Aerodynamics/Stress Analysis vs Cost (Material Z )
Total Cost (Z-Material) x 1000 Gas Bending Stress (Mpa)Efficiency %
Tota
l Cos
t x 1
000
($)
Gas B
endi
ng S
tress
(MPa
)
𝑨𝑵^𝟐=4.5 x 𝟏𝟎^𝟏𝟎
30 35 40 45 50 55 6087.687.787.887.9
8888.188.288.388.488.588.688.7
0.00
10000.00
20000.00
30000.00
40000.00
50000.00
60000.00
70000.00
Fuel Cost Difference/ Number of Bladesvs
Efficiency
Number of Blades
Efficie
ncy
%
Fuel
Cos
t Diff
eren
ce/ A
nnum
# %𝐵𝑙𝑎𝑑𝑒𝑠 𝑣𝑠 𝐸𝑓𝑓# 𝐵𝑙𝑎𝑑𝑒𝑠 𝑣𝑠 𝐹𝑢𝑒𝑙
𝐶𝑜𝑠𝑡 𝐷𝑖𝑓𝑓
𝑨𝑵^ = 4.5 x ^𝟐 𝟏𝟎 𝟏𝟎(Design 1)
Analysis
With increasing efficiency, total cost as well as gas bending stress has minimum value.
For 4.5 x Efficiency = 88.59 % Design 1
Analysis
Increasing number of blades lead to reduced efficiency and more Aerodynamic losses.
Further relative fuel cost increases with more number of blades pointing to the fact that greater quantity of fuel will be required to travel longer distances.
Chosen DesignCost of Engine – 10.88 M ($) ACME Aerospace Inc - Bringing Technologies of
Change
OFF- Design Analysis
800 900 1000 1100 1200 1300 1400 1500 1600 1700200.00
250.00
300.00
350.00
400.00
450.00
500.00
550.00
600.00
0
10
20
30
40
50
60
70
80
90
100
Performance Analysis of Peak Cycle Temperature
Peak cycle temperature (K)
Fuel
Con
sum
ptio
n (K
g/Hr
)
Efficie
ncy
(%)
Design (88.59 %)
Increasing Fuel Consumption
Efficiency
88 88.5 89 89.5 90 90.50
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Tip Control Clearance vs Efficiency
Efficiency (%)
Tip
Cont
rol C
lear
ance
(%)
Analysis
With increasing peak cycle temperature, fuel consumption increases since more fuel needs to be burned.
A sharp increase in efficiency to a maximum value and then it dips and remains constant.
With increasing ACC supply, tip clearance reduces and hence reduction in tip leakage losses
Decrease in efficiency with an increase in tip clearance
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Other Design Options : For lower than chosen value –
Design 2 • # of Blades = 38 More Weight • Increase in Cost = $ 6627 • Decrease in Centrifugal Tensile Stress =
44.73 MPa.
Design 3 • # of Blades = 41 More Weight • Increase in Cost = $ 30256 • Decrease in Centrifugal Tensile Stress =
89.46 MPa.
Efficiency Front Decrease in efficiency can be countered by
increasing peak cycle temperature slightly which will not affect our blade metallurgy as well.
Parameter Design-1 Design-2 Design-3Efficiency 88.59 88.55 88.36
AN^2 4.5*10^10 4*10^10 3.5*10^10No Of Blades 35 38 41
Centrifugal Tensile Stress (MPa) 402.573 357.84 313.11
Gas Bending Stress (MPa)
0.71212106 0.806799171 0.98
Total Cost ($) 10888097.35 10894725.07 10918354.12
Difference in Cost ($) - 6627.72 30256.76Difference in
Centrifugal Stress (MPa)
- 44.73 89.46
Chosen Design
900 1000 1100 1200 1300 1400 1500 1600 17000
102030405060708090
100
0
0.04
0.08
0.12Peak Cycle Temp vs SFC & Eff. %
Peak Cycle Temperature - K
Efficie
ncy
%
SFC
(kg/
hr.N
)
Efficiency %
SFC
Design 2/3
Slight increase in T
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Business Case…
Why ACME Aerospace … Team Synergy Customer consciousness Two pronged expertise
Aerodynamics + Stress
Inevitable Choice !
High efficiency Lesser Cost High “Power to Weight” Ratio
Less fuel consumption Better Specific Aircraft Range (SAR) miles/lbm of fuelLess fuel requirement More space for passengers …
Low Maintenance Downtime More Operational Time …
MORE REVENUES !
More options in design available
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MERCI… !ACME Aerospace Inc
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