1 RS,HN TURBO POWER– HPT Stage efficiency HPT Stage Efficiency Efficiency Improvements of High Pressure Turbine Stages Ranjan Saha (KTH) Hina Noor (KTH) Program Conference

2 RS,HN TURBO POWER– HPT Stage efficiency Outline of Presentation Background TurboAero project Work packages (WP1 and WP2) WP1 : Leading Edge Contouring WP2 : Reaction Degree Time Schedule

3 RS,HN TURBO POWER– HPT Stage efficiency Background Reduction of specific fuel consumption for 1% increased efficiency in each of the components Need for increase in efficiency of HPT Stage Adopted from lecture note of Vogt, D., 2008

4 RS,HN TURBO POWER – HPT Stage efficiency TurboAero Industry Design Toolbox Leading Edge Contouring ( WP1) Reaction degree (WP2) Increased turbine effectiveness 1D models and empirical rules for layout Geometry shaping methods/ contouring design rules Geometrical optimization tool Quality validation data Understanding of flow features

5 RS,HN TURBO POWER– HPT Stage efficiency Motivation The coherent understanding of leading edge contouring is lacking in open literature Results with bulb and fillet found in open literature are based on only linear cascade and mostly subsonic range WP1: Leading Edge Contouring

6 RS,HN TURBO POWER– HPT Stage efficiency Overview of Investigations Detailed literature study on Leading edge contouring Design study by CFD computations Experimental campaigns of final designs WP1: Leading Edge Contouring

7 RS,HN TURBO POWER– HPT Stage efficiency Fillet Objective: Decrease the intensity of h-s vortex Result: Decrease the overall secondary flow loss WP1: Leading Edge Contouring

8 RS,HN TURBO POWER– HPT Stage efficiency Traditional Method CAD Pre & Mesh Solve Post Process Design Change (Manual) Sculptor Method CAD Pre & Mesh Solve Post Process Sculptor WP1: Leading Edge Contouring Status of Computation: Design Optimization Through Sculptor, ICEM and CFX

9 RS,HN TURBO POWER– HPT Stage efficiency Initial Design Optimization WP1: Leading Edge Contouring

10 RS,HN TURBO POWER– HPT Stage efficiency Results Base line Simulatio n_1.uns WP1: Leading Edge Contouring Results with thin LE show less loss Degradation of mesh quality upon big deformation Necessity to have geometry with LE fillet and then optimization

11 RS,HN TURBO POWER– HPT Stage efficiency Simulation with Preliminary Design Fillet Using Ansys ICEM and CFX WP1: Leading Edge Contouring Comparison in stream-lines/hs vortex Without LE contouringWith LE contouring Comparison of the development of loss

12 RS,HN TURBO POWER– HPT Stage efficiency Experimental Campaign The Annular Sector Cascade (ASC) test rig 1Inflow 2Settling chamber 3First radial contraction 4Turbulence grid 5Second radial contraction 6Test sector with NGVs 7Outflow WP1: Leading Edge Contouring Test Matrices Upstream measurement Load measurement Downstream measurement Oil flow visualizations

13 RS,HN TURBO POWER– HPT Stage efficiency Fillet y/s=0.1 WP1: Leading Edge Contouring

14 RS,HN TURBO POWER– HPT Stage efficiency Upstream Measurement Relation bet. settling chamber pr. and probe pr WP1: Leading Edge Contouring

15 RS,HN TURBO POWER– HPT Stage efficiency Inlet Total Pressure Profile Decrease in total pressure δ~10% WP1: Leading Edge Contouring Inlet Profile:(Repeat)

16 RS,HN TURBO POWER– HPT Stage efficiency Present Status and Future Work Literature report on flow field in HPT (WP1.1) and leading edge contouring (WP1.2): Done On going: Experiment and CFD study Tek Lic V-2 : Submitted for internal reviewing Future work Experimental campaign Design optimization of the fillet by CFD Flow field investigation by tracer gas WP1: Leading Edge Contouring

17 RS,HN TURBO POWER– HPT Stage efficiency Introduction Modern industrial gas turbine with high firing temperature Features an efficient cooling system Little freedom to have advanced geometric features Aerodynamic design parameters implications on turbine design Choice of reaction degree and flow coefficient for given stage loading has strong impact on stage design Reaction Degree sets the relative rotor inlet temperature Research Need Selection criteria and guidelines for optimum reaction degree for cooled stage? WP2: Reaction Degree

18 RS,HN TURBO POWER– HPT Stage efficiency Methodology Preliminary Design Study Using ‘LUAXT Reduced Order Throughflow Design Tool’  Implement to 1D tool different loss estimation methods  Validate loss models  To establish optimum ‘R’ recommendations using validated loss model Profile generation and Blade to Blade CFD analysis using ‘Concepts NREC AxCent Design Tool’  Representing meanline velocity triangles obtained for recommended designs from preliminary study WP2: Reaction Degree

19 RS,HN TURBO POWER– HPT Stage efficiency Loss Model Validation Geometrical parameters Test data1 (Stage with high aspect ratio blades) Test data2 (Stage with low aspect ratio blades) Stator Blade Rotor Blade Stator Blade Rotor Blade Number of blades Pitch to chord ratio Aspect ratio Test data1: higher aspect ratio Test data2: low aspect ratio WP2: Reaction Degree

20 RS,HN TURBO POWER– HPT Stage efficiency Optimum Reaction Degree Representation Using Three Different Loss Estimation Methods Craig & Cox Loss Model WP2: Reaction Degree

21 RS,HN TURBO POWER– HPT Stage efficiency Simple Airfoil methods Pritchard methods Beziers methods Profile Design Parameters Meanline Design using LUAXT Mamaev Correlations Meanline Velocity Triangles --  2D Profile WP2: Reaction Degree

22 RS,HN TURBO POWER– HPT Stage efficiency Profile Generation UNKNOWN PARAMETER Chord (C) Pitch (s) Blade numbers (Z) Stagger angles (  ) LE wedge angles (  1 ) TE wedge angles (   ) Uncovered turning angle (  ) Throat length (a) Maximum thickness to chord ratio (t max /b) Uncovered Turning: Optimum pitch : Blade numbers : Throat length: WP2: Reaction Degree

23 RS,HN TURBO POWER– HPT Stage efficiency Profile Generation Case () Profile parameters Chord (b) Blade numbers (Z) Stagger angles (  ) Pitch/chord Axial chord Uncovered turning angle Throat length (a 2 ) Based on correlations VaneBlade Profiling tool VaneBlade Profile parameters Chord (b) Blade numbers (Z) Stagger angles (  ) Pitch/chord Axial chord Uncovered turning angle Throat length (a 2 ) WP2: Reaction Degree

24 RS,HN TURBO POWER– HPT Stage efficiency Blade Geometry--  Blade-to-Blade CFD WP2: Reaction Degree

25 RS,HN TURBO POWER– HPT Stage efficiency Conclusions Preliminary design study Different loss model implementation Loss model validation Craig and Cox ‘CC’ predictions more accurate over all lower loss, for lower PR at given stage loading Choice of relative flow velocity to compute secondary loss is justifiable for compressible flow more reasonable choice of arc length instead of chord to compute profile loss computes Reynolds influence based on throat length more correctly Optimum reaction degree for cooled stage Profiling of recommended stage designs Reasonable cascade Recommendations can be considered as reliable Slight differences in computed meanline and CFD results 1D-2D design iterations to adjust the throat WP2: Reaction Degree

26 RS,HN TURBO POWER– HPT Stage efficiency Future Work Implement and test Denton Loss Estimation method Experimental validation of the 1D Loss estimation Experimental data from KTH Test Rig Validating cooling model and sensitivity to cooling model variation Integration of correlations Guidelines to profiling process and profiling optimization strategies 1D design models improvements to represent modern profile families and operating ranges Development of new design guidelines and rules for modern cooled turbine stages WP2: Reaction Degree

27 RS,HN TURBO POWER– HPT Stage efficiency Work Packages & Deliverables (First) WP1(Leading Edge contouring) & WP2(Reaction degree) Deliverable No Description D 1.1 D 2.1 Literature study report Literature report and technical report D 1.2 D 2.2 Leading edge contouring (lit. report) Systhesis of full parametric study (report) D 1.3 D 2.3 Synthesis of design and numerical calculations (report) Synthesis of through flow calculations (report). 1-2 international publications D 1.4Synthesis of experimental results with numerical comparisons. 1-2 international publications Work Package NoDescription WP1.1 & WP2.1Literature Study, cycle & flow path calculations WP1.2Detailed literature study on Leading edge contouring WP2.2Mean line calculations (parametric study, loss model analysis) WP1.3Design study (of leading edge contouring) & steady CFD computation of final designs WP2.3Throughflow calculations WP1.4Experimental campaigns of 2-3 different designs

28 RS,HN TURBO POWER– HPT Stage efficiency Time Schedule WP1(Leading Edge contouring) & WP2(Reaction degree) Work package WP 1.1 D1.1 WP 2.1 D2.1 WP 1.2 D1.2 WP 2.2D2.2 WP 1.3 D1.3 WP 2.3 D2.3 WP 1.4 D1.4 Delivered To be delivered

29 RS,HN TURBO POWER– HPT Stage efficiency Deliverables WP2: Reaction Degree Conference Publication: European Turbomachinery Conference 2011 Internal Reports: 3 reports Licentiate: Draft submitted for review WP1: Leading Edge Contouring Internal Reports: 3 reports Licentiate: Draft submitted for review

30 RS,HN TURBO POWER– HPT Stage efficiency Msc. Thesis TitleStatus A Numerical Parametric Study of an Annular Sector Cascade for Experimental Aerodynamic Testing Completed Loss Measurements and Endwall Flow Investigations on an Annular Sector Completed Load, Secondary Flow and Turbulence Measurements on Film Cooled Nozzle Guide Vanes in a Transonic Annular Sector Completed Study of Blade Leading Edge With Fillet to Assess the Effect of Secondary Flow of High Pressure Turbine Stage by Computational Fluid Dynamics Completed A Parametric Study to Investigate One Dimensional Design of a High Pressure Industrial Gas Turbine On going Implementing loss prediction methods to an existing one-dimensional Axial Turbine Design Program On going CFD comparison of blade leading edge contouring by fillet and baseline shape of a turbine vane to decrease the secondary flow in a transonic cascade On going

31 RS,HN TURBO POWER– HPT Stage efficiency THANK YOU Questions??