Automated Ultrasonic Dimensional and Defect Inspection of Complex Geometry Gas Turbine Airfoil Shapes

1982 ◽  
pp. 71-77
Author(s):  
I. M. Matay ◽  
C. W. Fetheroff ◽  
P. E. Neal ◽  
S. D. Murphy ◽  
T. Derkacs
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Defect Inspection

Compressor Performance and Operability in Swirl Distortion

2010 ◽  
Author(s):  
Yogi Sheoran ◽  
Bruce Bouldin ◽  
P. Murali Krishnan
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Full Range ◽  
Axial Compressor ◽  
Cfd Model ◽  
Generator System ◽  
Sliding Mesh ◽  
Wide Range ◽  
Compressor Performance ◽  
The Impact

Inlet swirl distortion has become a major area of concern in the gas turbine engine community. Gas turbine engines are increasingly installed with more complicated and tortuous inlet systems, like those found on embedded installations on Unmanned Aerial Vehicles (UAVs). These inlet systems can produce complex swirl patterns in addition to total pressure distortion. The effect of swirl distortion on engine or compressor performance and operability must be evaluated. The gas turbine community is developing methodologies to measure and characterize swirl distortion. There is a strong need to develop a database containing the impact of a range of swirl distortion patterns on a compressor performance and operability. A recent paper presented by the authors described a versatile swirl distortion generator system that produced a wide range of swirl distortion patterns of a prescribed strength, including bulk swirl, twin swirl and offset swirl. The design of these swirl generators greatly improved the understanding of the formation of swirl. The next step of this process is to understand the effect of swirl on compressor performance. A previously published paper by the authors used parallel compressor analysis to map out different speed lines that resulted from different types of swirl distortion. For the study described in this paper, a computational fluid dynamics (CFD) model is used to couple upstream swirl generator geometry to a single stage of an axial compressor in order to generate a family of compressor speed lines. The complex geometry of the analyzed swirl generators requires that the full 360° compressor be included in the CFD model. A full compressor can be modeled several ways in a CFD analysis, including sliding mesh and frozen rotor techniques. For a single operating condition, a study was conducted using both of these techniques to determine the best method given the large size of the CFD model and the number of data points that needed to be run to generate speed lines. This study compared the CFD results for the undistorted compressor at 100% speed to comparable test data. Results of this study indicated that the frozen rotor approach provided just as accurate results as the sliding mesh but with a greatly reduced cycle time. Once the CFD approach was calibrated, the same techniques were used to determine compressor performance and operability when a full range of swirl distortion patterns were generated by upstream swirl generators. The compressor speed line shift due to co-rotating and counter-rotating bulk swirl resulted in a predictable performance and operability shift. Of particular importance is the compressor performance and operability resulting from an exposure to a set of paired swirl distortions. The CFD generated speed lines follow similar trends to those produced by parallel compressor analysis.

scholarly journals Numerical Simulation of Fluid Flow and Combustion in Gas Turbine Combustors

1993 ◽  
Author(s):  
Inge R. Gran ◽  
M. C. Melaaen ◽  
F. Magnussen
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Reacting Flows ◽  
Staggered Grid ◽  
Computational Grids ◽  
Turbulent Reacting Flows ◽  
Combustion Chambers ◽  
Gas Turbine Combustors ◽  
Elliptic Differential Equations ◽  
Finite Volume Approach

The finite-volume approach together with body-fitted curvilinear non-orthogonal coordinates and a non-staggered grid arrangement is used for investigating turbulent reacting flows inside gas turbine combustion chambers. The computational grids are generated by solving elliptic differential equations, permitting an accurate description of the complex geometry of commercial gas turbine combustors. Different combustion models are briefly discussed with a view to their suitability for practical combustor predictions. The k-ε model and the Eddy Dissipation Concept are selected to account for the turbulent combustion in the present study. The governing equations and coordinate transformations needed to derive the discretized equations are reviewed. One isothermal and two combusting flow fields are calculated. The calculations are in reasonable agreement with measurements, but the results should be improved by grid refinement and by using a better turbulence model.

scholarly journals Quasi-3D Numerical Computations on a Film-Cooled Gas Turbine Nozzle

1998 ◽  
Author(s):  
F. Bassi ◽  
S. Rebay ◽  
M. Savini
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Complex Geometry ◽  
Computational Effort ◽  
Navier Stokes ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Density Ratios ◽  
The Impact

The aim of this work is to assess the accuracy of a “quasi-3d” Navier-Stokes solver equipped with the k-ω turbulence model in the computation of a film-cooled gas turbine blade under a variety of flow conditions. The “quasi-3d” formulation was chosen as a cheap approach to investigate a large number of test conditions for a nozzle of complex geometry (around 400 cooling holes) which would require a large computational effort for a truly 3d simulation. The developed code has been used to investigate the influence of various cooling geometries and blowing conditions (mass flow rate and/or density ratios) on the aerodynamic behaviour of the cascade (in terms of loading, losses and flow angles) and their impact on the mixing process downstream of the trailing edge. The investigated nozzle is an advanced design turbine vane working in high subsonic regime. It is characterized by a marked endwall contouring at the casing and by the presence of 12 rows of holes (including a trailing edge row of slots) so as to obtain full-coverage film-cooling of the solid surfaces. This vane has been extensively tested in the Politecnico di Milano Fluid Dynamics Laboratory (formerly C.N.P.M.) blowdown transonic wind tunnel and a great amount of data are therefore available for validation purposes. The uselfulness of the proposed approach is fully analyzed and discussed throughout the paper and it is shown that the relation between the cascade performance and the variation of the investigated parameters is correctly described. In addition we address and discuss which ejection boundary conditions and which loss definitions are best suited for a meaningful comparison with the experimental measurements. In conclusion, in the case considered the developed code seems to be a valuable tool to determine the impact of film-cooling on the aerodynamic performance of a gas turbine blade.

Compressor Performance and Operability in Swirl Distortion

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Yogi Sheoran ◽  
Bruce Bouldin ◽  
P. Murali Krishnan
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Full Range ◽  
Axial Compressor ◽  
Cfd Model ◽  
Generator System ◽  
Sliding Mesh ◽  
Wide Range ◽  
Compressor Performance ◽  
The Impact

Inlet swirl distortion has become a major area of concern in the gas turbine engine community. Gas turbine engines are increasingly installed with more complicated and tortuous inlet systems such as those found on embedded installations on unmanned aerial vehicles. These inlet systems can produce complex swirl patterns in addition to total pressure distortion. The effect of swirl distortion on engine or compressor performance and operability must be evaluated. The gas turbine community is developing methodologies to measure and characterize swirl distortion. There is a strong need to develop a database containing the impact of a range of swirl distortion patterns on a compressor performance and operability. A recent paper presented by the authors described a versatile swirl distortion generator system that produced a wide range of swirl distortion patterns of a prescribed strength, including bulk swirl, twin swirl, and offset swirl. The design of these swirl generators greatly improved the understanding of the formation of swirl. The next step of this process is to understand the effect of swirl on compressor performance. A previously published paper by the authors used parallel compressor analysis to map out different speed lines that resulted from different types of swirl distortion. For the study described in this paper, a computational fluid dynamics (CFD) model is used to couple upstream swirl generator geometry to a single stage of an axial compressor in order to generate a family of compressor speed lines. The complex geometry of the analyzed swirl generators requires that the full 360 deg compressor be included in the CFD model. A full compressor can be modeled several ways in a CFD analysis, including sliding mesh and frozen rotor techniques. For a single operating condition, a study was conducted using both of these techniques to determine the best method, given the large size of the CFD model and the number of data points that needed to be run to generate speed lines. This study compared the CFD results for the undistorted compressor at 100% speed to comparable test data. Results of this study indicated that the frozen rotor approach provided just as accurate results as the sliding mesh but with a greatly reduced cycle time. Once the CFD approach was calibrated, the same techniques were used to determine compressor performance and operability when a full range of swirl distortion patterns were generated by upstream swirl generators. The compressor speed line shift due to co-rotating and counter-rotating bulk swirl resulted in a predictable performance and operability shift. Of particular importance is the compressor performance and operability resulting from an exposure to a set of paired swirl distortions. The CFD generated speed lines follow similar trends to those produced by parallel compressor analysis.

Large eddy simulation applications in gas turbines

2009 ◽  
Vol 367 (1899) ◽  
pp. 2827-2838 ◽  
Author(s):  
Kevin Menzies
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Complex Geometry ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Wide Range ◽  
Large Eddy ◽  
Design Cycle ◽  
Flow Phenomena

The gas turbine presents significant challenges to any computational fluid dynamics techniques. The combination of a wide range of flow phenomena with complex geometry is difficult to model in the context of Reynolds-averaged Navier–Stokes (RANS) solvers. We review the potential for large eddy simulation (LES) in modelling the flow in the different components of the gas turbine during a practical engineering design cycle. We show that while LES has demonstrated considerable promise for reliable prediction of many flows in the engine that are difficult for RANS it is not a panacea and considerable application challenges remain. However, for many flows, especially those dominated by shear layer mixing such as in combustion chambers and exhausts, LES has demonstrated a clear superiority over RANS for moderately complex geometries although at significantly higher cost which will remain an issue in making the calculations relevant within the design cycle.

Measurements and Predictions of a Highly Turbulent Flowfield in a Turbine Vane Passage

2000 ◽  
Vol 122 (4) ◽  
pp. 666-676 ◽  
Author(s):  
R. W. Radomsky ◽  
K. A. Thole
Keyword(s):  
Kinetic Energy ◽  
Turbulent Flow ◽  
Gas Turbine ◽  
Turbulent Kinetic Energy ◽  
Reynolds Stress ◽  
Complex Geometry ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Mean Flow

As highly turbulent flow passes through downstream airfoil passages in a gas turbine engine, it is subjected to a complex geometry designed to accelerate and turn the flow. This acceleration and streamline curvature subject the turbulent flow to high mean flow strains. This paper presents both experimental measurements and computational predictions for highly turbulent flow as it progresses through a passage of a gas turbine stator vane. Three-component velocity fields at the vane midspan were measured for inlet turbulence levels of 0.6%, 10%, and 19.5%. The turbulent kinetic energy increased through the passage by 130% for the 10% inlet turbulence and, because the dissipation rate was higher for the 19.5% inlet turbulence, the turbulent kinetic energy increased by only 31%. With a mean flow acceleration of five through the passage, the exiting local turbulence levels were 3% and 6% for the respective 10% and 19.5% inlet turbulence levels. Computational RANS predictions were compared with the measurements using four different turbulence models including the k-ε, Renormalization Group (RNG) k-ε, realizable k-ε, and Reynolds stress model. The results indicate that the predictions using the Reynolds stress model most closely agreed with the measurements as compared with the other turbulence models with better agreement for the 10% case than the 19.5% case. [S0098-2202(00)00804-X]

Applying CAx Technology for the Design of a Gas Turbine Exhaust

2003 ◽  
Author(s):  
L. Itter ◽  
M. Cagna ◽  
A. Wiedermann ◽  
M. Boehle
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Complex Geometry ◽  
Exhaust System ◽  
Cad System ◽  
Leading Role ◽  
Market Requirements ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Today’s market for gas turbines is getting bigger since there is a huge demand for power generation and mechanical drive applications. To meet the market requirements gas turbine components have to be very efficient to play a leading role. In order to accelerate component improvement the introduction of integrated CAx Technology is a key to achieve a less time-consuming and therefore cheaper design. This paper will describe a procedure which can be used to design an exhaust system for gas turbines with hot-end drive. It shows how to combine various technologies like CAD and CFD and make them work together rapidly. Firstly a 1D design is done and compared with a performance chart of conventional use. Then, a 2D parametric study of a 90 degree bend will be performed by the combination of a CAD-system and a CFD-solver. Thirdly a full 3D-simulation of the entire exhaust will be performed with a calibrated solver. Different complex geometry modifications are applied and their influence on the performance of the exhaust will be discussed.

Simulating Turbulent Flows in Complex Geometries

2003 ◽  
Author(s):  
Krishnan Mahesh ◽  
George Constantinescu ◽  
Parviz Moin
Keyword(s):  
Gas Turbine ◽  
Turbulent Flows ◽  
Complex Geometry ◽  
Reynolds Numbers ◽  
Complex Geometries ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Eddy Simulation ◽  
Large Eddy ◽  
High Reynolds

We discuss development of a numerical algorithm, and solver capable of performing large-eddy simulation (LES) in geometries as complex as the combustor of a gas-turbine engine. The algorithm is developed for unstructured grids, is non-dissipative, yet robust at high Reynolds numbers on highly skewed grids. Results from validation in simple geometries is shown along with simulation results in the exceedingly complex geometry of a Pratt & Whitney gas turbine combustor.

scholarly journals Correction to: Gas turbine computational flow and structure analysis with isogeometric discretization and a complex-geometry mesh generation method

2020 ◽  
Author(s):  
Yuri Bazilevs ◽  
Kenji Takizawa ◽  
Michael C. H. Wu ◽  
Takashi Kuraishi ◽  
Reha Avsar ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Structure Analysis ◽  
Mesh Generation ◽  
Complex Geometry ◽  
Isogeometric Discretization

An earlier version of this article included a number of typesetting mistakes. These were corrected on October 16, 2020. The publisher apologizes for the errors made during production. The symbol “Λn” was incorrectly published as “Γn” in equations 46 and 47. The correct equations are provided in this correction.

scholarly journals Gas turbine computational flow and structure analysis with isogeometric discretization and a complex-geometry mesh generation method

2020 ◽  
Author(s):  
Yuri Bazilevs ◽  
Kenji Takizawa ◽  
Michael C. H. Wu ◽  
Takashi Kuraishi ◽  
Reha Avsar ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Mesh Generation ◽  
Compressible Flows ◽  
Complex Geometry ◽  
Flow Direction ◽  
Flow Simulation ◽  
Free Vibration Analysis ◽  
Structural Mechanics ◽  
Superior Performance ◽  
Courant Number

AbstractA recently introduced NURBS mesh generation method for complex-geometry Isogeometric Analysis (IGA) is applied to building a high-quality mesh for a gas turbine. The compressible flow in the turbine is computed using the IGA and a stabilized method with improved discontinuity-capturing, weakly-enforced no-slip boundary-condition, and sliding-interface operators. The IGA results are compared with the results from the stabilized finite element simulation to reveal superior performance of the NURBS-based approach. Free-vibration analysis of the turbine rotor using the structural mechanics NURBS mesh is also carried out and shows that the NURBS mesh generation method can be used also in structural mechanics analysis. With the flow field from the NURBS-based turbine flow simulation, the Courant number is computed based on the NURBS mesh local length scale in the flow direction to show some of the other positive features of the mesh generation framework. The work presented further advances the IGA as a fully-integrated and robust design-to-analysis framework, and the IGA-based complex-geometry flow computation with moving boundaries and interfaces represents the first of its kind for compressible flows.

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