Gas Turbine Project
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This document discusses the design process for a high pressure turbine (HPT). It includes: 1) Performing cycle calculations to obtain inlet parameters and determining key design variables. 2) Developing the meanline design including velocity triangles and geometric parameters for vanes and blades. 3) Calculating losses and efficiencies using loss prediction models. 4) Considering off-design performance with changes to operating conditions. 5) Comparing acquisition and overhauling costs of different blade materials to determine the most economical design while meeting efficiency targets.
Gas Turbine Project
- 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 %
- 4. HPT HPT HPT Exhaus LPC HPC Combustor Combust LPT PT Exhaus Variable LPC Inlet HPC Inlet Inlet Inlet Outlet LPT Inlet PT Inlet t Outlet Outlet Inlet or Outlet Outlet Outlet t Inlet Vane Blade Blade Outlet Mass flow 12.00 12.00 12.00 12.00 10.80 11.02 11.02 11.62 11.62 11.80 11.80 11.92 11.92 12.04 12.04 (lb/sec) Po (bar) 0.875 3.50 3.50 10.50 10.50 10.34 10.34 9.99 4.24 4.24 2.10 2.08 0.888 0.888 0.875 1200.1 1017.0 To (K) 296.48 462.10 462.10 662.56 662.56 1233.90 1233.90 1017.00 868.02 868.02 714.25 714.25 714.25 3 0 1106.2 W (kW) 904.80 1095.16 913.94 952.89 2
- 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
- 10. Geometric Parameters HUB & TIP VELOCITY TRIANGLES VANE GEOMETRY BLADE GEOMETRY HUB, MEANLINE AND TIP HUB, MEANLINE AND TIP ηtt CALCULATION ηtt NO & GEOMETRY OPTIMAL? YES Vane geometry Hub Mean Tip Airfoil count 22 22 22 Axial chord (in) 0,88 0,88 1,01 Leading edge diameter (in) 0,04 0,04 0,04 Trailing edge diameter (in) 0,05 0,05 0,05 Stagger angle (deg) 56,78 56,78 51,22 Metal angle (deg) inlet= -10 ; exit = 74,27 inlet= -10 ; exit = 72,10 inlet= -10 ; exit = 69,98 Throat opening (in) 0,34 0,34 0,40 Radio (in) 3,36 3,93 4,49 Blade geometry Hub Mean Tip Airfoil count 49 49 49 Axial chord (in) 0,65 0,59 0,42 Leading edge diameter (in) 0,02 0,02 0,02 Trailing edge diameter (in) 0,03 0,03 0,03 Stagger angle (deg) 18,47 29,73 51,56 Metal angle (deg) inlet= 52,07 ; exit = 61,31 inlet= 26,35 ; exit = 63,21 inlet= -10,71 ; exit = 65,02 Throat opening (in) 0,18 0,23 0,22 Radio (in) 3,36 3,86 4,35
- 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
- 14. Selection of best concept. 300000 Savings ($) 250000 200000 Fuel 150000 cost 100000 50000 ($) 0 Savings ($) -50000 86 88 90 92 -100000 -150000 HPT efficiency(% )
- 15. THANK YOU !