2. • Cycle analysis and calculation of inlet and outlet conditions
of each components, component work, SHP, Thermal
efficiency and SFC
• From the ranges given, choose the best combination that
can match or approach the required efficiency.
• Generate the Geometry(No of vanes and blades, gas and
metal angles etc..)
• Off design performance
• Factory standard cost Vs stage efficiency
• Acquisition cost Vs operational cost
• Optimum design (compromise between efficiency and
cost)
3. From the cycle calculation we obtained the key parameters,
At the Inlet of the LPC we are using the International HPT entry 1233 K
Standard Atmosphere table to obtain the static pressure and temperature
assuming static pressure = stagnation pressure
PT work 952.89 KW
• We are considering the effect of the HPT Vane cooling
air to obtain To at the blade inlet SFC .38 Kg/Kwh
• At LPT inlet we are neglecting the effect in temperature of
disk cooling air Thermal Efficiency 25 %
5. HPT DESIGN
INSTALLATION NETWORK TEAM
START
GASPATH
INPUT DATA
SCHEMATICS
PART A CYCLE DESIGN VARIABLES
CALCULATIONS SET-UP
CHARACTERISTICS
(GIVEN)
PARAMETERS PARAMETERS
VELOCITY TRIANGLES
MEANLINE
DESIGN
AT INLET & EXIT OF
EACH COMPONENT
FREE VORTEX
DESIGN
HUB & TIP
DESIGN
HUB & TIP
VELOCITY
TRIANGLES
BLADE GEOMETRY
GEOMETRIC PARAMETERS
HUB, MEANLINE
AND TIP ηtt
VANE GEOMETRY CALCULATION
HUB, MEANLINE
AND TIP ηtt
NO & GEOMETRY
OPTIMAL?
YES
AMDC LOSS
SYSTEM
LOSS CALCULATIONS & EFFICIENCY
BLADE
LOSS COEFFICIENTS
Kp*fRe + Ks + KTE ηtto
(Tip Clearance = 0)
VANE Kclr
LOSS COEFFICIENTS calculation
Kp*fRe + Ks + KTE
ηtt
END DESIGN
6. HPT Design – Input data
START
GIVEN CHARACTERISTICS
Component Parameter Value
Inlet Mach number 0,125
Inlet Swirl relative to axial (deg) -10
CHARACTERISTICS PART A – HPT CYCLE GASPATH
(GIVEN) CALCULATIONS SCHEMATICS
Stage Exit Mach number 0,3 to 0,45
Exit Swirl (deg) 10 to 30
Target field life (hours) 5000
Aspect ratio 0,7
Vane Zweifel Coefficient at mean 0,70 to 0,80
Trailing edge thickness minimum (in) 0,045
Aspect ratio 1,45
DESIGN VARIABLES Blade Zweifel Coefficient at mean 0,85 to 0,95
SET-UP Trailing edge thickness minimum (in) 0,025
Blade Containment AN^2 NOT exceed 4 x 10^10
Consideration Rim Speed limit 1200 ft/s
Design Variables Set-up
VELOCITY TRIANGLES
Parameter EXIT OF
AT INLET &
EACH COMPONENT
Value
Exit Mach number 0,45
Exit Swirl (deg) 20
Zweifel Coefficient at mean vane 0,70
Zweifel Coefficient at mean blade 0,85
Reaction: (T2-T3) / (T1-T3) 0,4
AN^2 4E+10
Rim Speed (ft/s) 1200
7. Assumptions
• Po,To at Vane outlet = Po, To at Blade Inlet
• Cx Hub = Cx Mean = Cx Tip ( applying free vortex theory)
• Incidence and deviation = 0 (as design conditions)
• Because of variable section at vanes we are using r average and h average for vane design
• For Loss Calculation we are following the Kacker & Okapuu Loss Prediction Model
explained in class.
• Delta tc/h = 1,8%
Critical values
• AN^2=maximal (4 x10^10) to obtain the high efficiency
• Rim speed (U hub) maximal = 1200 ft/s to obtain high efficiency
• Vane Zweifel coefficient at mean=0,7 (using minimum value to maximize quantity of
vanes)
• Blade Zweifel coefficient at mean=0,85 to reduce blade loading
8. Meanline Design
Parameters
VELOCITY DIAGRAM (meanline)
1 2 3
Variable
Vane Inlet Blade Inlet Blade Outlet
mass flow (lb/s) 11,02 11,62 11,62
To (R) 2221,02 2160,23 1830,61
T (R) 2215,26 1944,42 1770,91
Po (bar) 10,34 9,99 4,24
P (bar) 10,23 6,56 3,71
Mn 0,13 0,82 0,45
Mn rel 0,28 0,94
densité (lb/ft^3) 0,1809 0,123 0,082
A (in^2) 31,654 23,957 23,957
U (ft/s) 1376,00 1376,00
alpha (deg) -10,00 72,10 20,00
beta (deg) 26,35 63,21
C (ft/s) 281,40 1721,35 905,76
Ca (ft/s) 277,13 529,02 851,14
Cw (ft/s) -48,86 1638,04 309,79
V (ft/s) 590,36 1888,47
φ 0,38 0,62
ψ 2,83
R 0,40
9. Hub & Tip Design
Parameters
FREE VORTEX DESIGN
Ca constant with radius r
&
Cw * radius = constant
HUB & TIP
VELOCITY TRIANGLES
11. Loss Calculation and
Efficiency
ηtt
& GEOMETRY
OPTIMAL?
YES
AMDC LOSS SYSTEM
VANE BLADE
LOSS COEFFICIENTS LOSS COEFFICIENTS
Kp*fRe + Ks + KTE Kp*fRe + Ks + KTE
ηtto
(Tip Clearance = 0)
Kclr calculation
(Assuming delta tc/h = 1.8%)
ηtt
END
DESIGN
12. Off-Design
Considerations
• U at meanline reduced by 10%
• Mass flow = Mass flow design
• Alpha2 = Alpha 2 Design
• Beta 3 = Beta 3 Design
• C2 = C2 Design
• Ca2= Ca2 Design Methodology
• Pitch = Pitch Design • Kp and Ks are calculated from Moustapha et al.
Correlation for Turbine Airfoils
• fRe, KTE and Kclr are calculated from the
results from the new velocity triangles
Results
• Incidence of 10.72 degrees
• KT in the blades increase from 0.1 to 0.16
• Efficiency reduces to 85,6%
13. MATERIAL and FSC TO CUTOMER
Blade Acquisit Overhaulin TOTAL
materia ion Cost g Cost
l
X 16660 2,40,000 256660
Y 12495 3,20,000 332495
Z 29155 1,60,000 189155
350000
Blade stress
300000 ρ
σ = (2⫪ AN²)
250000
200000 X
150000 Y
Economical benefits
100000 Z
50000
0
Acquisition Overhauling Total cost
cost cost