Structural Deflection's Impact in Turbine Stator Well Heat Transfer

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Julien Pohl ◽  
Harvey M. Thompson ◽  
Antonio Guijarro Valencia ◽  
Gregorio López Juste ◽  
Vincenzo Fico ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Test Data ◽  
Internal Flow ◽  
Radial Component ◽  
Element Analysis ◽  
Turbine Stator ◽  
Air Temperatures ◽  
Air Supply ◽  
Commercial Solver ◽  
The Impact

In the most evolved designs, it is common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall performance and to minimize the engine-specific fuel consumption (SFC). To prevent overheating of the materials and thus the reduction of the component life, an internal flow system is required to cool the critical engine parts and to protect them. This paper shows a practical application and extension of the methodology developed during the five-year research program, main annulus gas path interaction (MAGPI). Extensive use was made of finite element analysis (FEA (solids)) and computational fluid dynamics (CFD (fluid)) modeling techniques to understand the thermomechanical behavior of a dedicated turbine stator well cavity rig, due to the interaction of cooling air supply with the main annulus. Previous work based on the same rig showed difficulties in matching predictions to thermocouple measurements near the rim seal gap. In this investigation, two different types of turbine stator well geometries were analyzed, where—in contrast to previous analyses—further use was made of the experimentally measured radial component displacements during hot running in the rig. The structural deflections were applied to the existing models to evaluate the impact inflow interactions and heat transfer. Additionally, to the already evaluated test cases without net ingestion, cases simulating engine deterioration with net ingestion were validated against the available test data, also taking into account cold and hot running seal clearances. 3D CFD simulations were conducted using the commercial solver fluent coupled to the in-house FEA tool SC03 to validate against available test data of the dedicated rig.

Structural Deflection’s Impact in Turbine Stator Well Heat Transfer

2016 ◽  
Author(s):  
Julien Pohl ◽  
Harvey Thompson ◽  
Antonio Guijarro Valencia ◽  
Gregorio López Juste ◽  
Vincenzo Fico ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Test Data ◽  
Internal Flow ◽  
Research Programme ◽  
Turbine Stator ◽  
Air Temperatures ◽  
Air Supply ◽  
Flow Interactions ◽  
Commercial Solver ◽  
The Impact

In the most evolved designs, it is common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall performance and to minimise the engine specific fuel consumption (SFC). To prevent overheating of the materials and thus the reduction of the component life, an internal flow system is required to cool the critical engine parts and to protect them. This paper shows a practical application and extension of the methodology developed during the five year research programme MAGPI. Extensive use was made of FEA (solids) and CFD (fluid) modelling techniques to understand the thermo-mechanical behaviour of a dedicated turbine stator well cavity rig, due to the interaction of cooling air supply with the main annulus. Previous work based on the same rig showed difficulties in matching predictions to thermocouple measurements near the rim seal gap. In this investigation, two different types of turbine stator well geometries were analysed, where further use was made of existing measurements of hot running seal clearances in the rig. The structural deflections were applied to the existing models to evaluate the impact in flow interactions and heat transfer. Additionally to the already evaluated test cases without net ingestion, cases simulating engine deterioration with net ingestion were validated against the available test data, also taking into account cold and hot running seal clearances. 3D CFD simulations were conducted using the commercial solver FLUENT coupled to the in-house FEA tool SC03 to validate against available test data of the dedicated rig.

Innovative Turbine Stator Well Design Using a Kriging-Assisted Optimization Method

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Julien Pohl ◽  
Harvey M. Thompson ◽  
Ralf C. Schlaps ◽  
Shahrokh Shahpar ◽  
Vincenzo Fico ◽  
...  
Keyword(s):  
Engine Performance ◽  
Internal Flow ◽  
Optimization Method ◽  
Optimized Design ◽  
Element Analysis ◽  
Baseline Design ◽  
Turbine Stator ◽  
Air Temperatures ◽  
Design Variables ◽  
Deflector Plate

At present, it is a common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall engine performance and to minimize the engine specific fuel consumption. To prevent overheating of the materials and thus the reduction of component life, an internal flow system is required to cool and protect the critical engine parts. Previous studies have shown that the insertion of a deflector plate in turbine cavities leads to a more effective use of reduced cooling air, since the coolant is fed more effectively into the disk boundary layer. This paper describes a flexible design parameterization of an engine representative turbine stator well geometry with stationary deflector plate and its implementation within an automated design optimization process using automatic meshing and steady-state computational fluid dynamics (CFD). Special attention and effort is turned to the flexibility of the parameterization method in order to reduce the number of design variables to a minimum on the one hand, but increasing the design space flexibility and generality on the other. Finally, the optimized design is evaluated using a previously validated conjugate heat transfer method (by coupling a finite element analysis (FEA) to CFD) and compared against both the nonoptimized deflector design and a reference baseline design without a deflector plate.

Heat Transfer in Turbine Hub Cavities Adjacent to the Main Gas Path Including FE-CFD Coupled Thermal Analysis

2011 ◽  
Author(s):  
Antonio Guijarro Valencia ◽  
Jeffrey A. Dixon ◽  
Attilio Guardini ◽  
Daniel D. Coren ◽  
Daniel Eastwood
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Flow Distribution ◽  
Research Programme ◽  
Coupled Analysis ◽  
Analysis Method ◽  
Fe Modelling ◽  
Turbine Stator ◽  
Fuel Burn ◽  
Air Supply

Reliable means of predicting heat transfer in cavities adjacent to the main gas path are increasingly being sought by engineers involved in the design of gas turbines. In this paper an up-dated analysis of the interim results from an extended research programme, MAGPI, sponsored by the EU and several leading gas turbine manufactures and universities, will be presented. Extensive use is made of CFD and FE modelling techniques to understand the thermo-mechanical behaviour and convective heat transfer of a turbine stator well cavity, including the interaction of cooling air supply with the main annulus gas. It is also important to establish the hot running seal clearances for a full understanding of the cooling flow distribution and heat transfer in the cavity. The objective of the study has been to provide a means of optimising the design of such cavities (see Figure 1) for maintaining a safe environment for critical parts, such as disc rims and blade fixings, whilst maximising the turbine efficiency by means of reducing the fuel burn and emissions penalties associated with the secondary airflow system. The modelling methods employed have been validated against data gathered from a dedicated two-stage turbine rig, running at engine representative conditions. Extensive measurements are available for a range of flow conditions and alternative cooling arrangements. The analysis method has been used to inform a design change which will be tested in a second test phase. Data from this test will also be used to further benchmark the analysis method. Comparisons are provided between the predictions and measurements from the original configuration, turbine stator well component temperature survey, including the use of a coupled analysis technique between FE and CFD solutions.

scholarly journals On Characteristics of Ferritic Steel Determined during the Uniaxial Tensile Test

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3117
Author(s):  
Ihor Dzioba ◽  
Sebastian Lipiec ◽  
Robert Pala ◽  
Piotr Furmanczyk
Keyword(s):  
Tensile Test ◽  
Test Data ◽  
Constitutive Relationship ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Element Analysis ◽  
Material Weakness ◽  
Uniaxial Test ◽  
The Impact ◽  
Tensile Test Data

Tensile uniaxial test is typically used to determine the strength and plasticity of a material. Nominal (engineering) stress-strain relationship is suitable for determining properties when elastic strain dominates (e.g., yield strength, Young’s modulus). For loading conditions where plastic deformation is significant (in front of a crack tip or in a neck), the use of true stress and strain values and the relationship between them are required. Under these conditions, the dependence between the true values of stresses and strains should be treated as a characteristic—a constitutive relationship of the material. This article presents several methodologies to develop a constitutive relationship for S355 steel from tensile test data. The constitutive relationship developed was incorporated into a finite element analysis of the tension test and verified with the measured tensile test data. The method of the constitutive relationship defining takes into account the impact of high plastic strain, the triaxiality stress factor, Lode coefficient, and material weakness due to the formation of microvoids, which leads to obtained correctly results by FEM (finite elements method) calculation. The different variants of constitutive relationships were applied to the FEM loading simulation of the three-point bending SENB (single edge notched bend) specimen to evaluate their applicability to the calculation of mechanical fields in the presence of a crack.

Heat Transfer in Turbine Hub Cavities Adjacent to the Main Gas Path

2010 ◽  
Author(s):  
Jeffrey A. Dixon ◽  
Antonio Guijarro ◽  
Andreas Bauknecht ◽  
Daniel Coren ◽  
Nick Atkins
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Research Programme ◽  
Fe Modelling ◽  
Turbine Stator ◽  
Turbine Efficiency ◽  
Fuel Burn ◽  
Air Supply ◽  
Modelling Techniques ◽  
Cooling Air

Reliable means of predicting heat transfer in cavities adjacent to the main gas path are increasingly being sought by engineers involved in the design of gas turbines. In this paper an interim summary of the results of a four-year research programme sponsored by the EU and several leading gas turbine manufactures and universities will be presented. Extensive use is made of CFD and FE modelling techniques to understand the thermo-mechanical behaviour of a turbine stator well cavity, including the interaction of cooling air supply with the main annulus gas (see Figure 1). The objective of the study has been to provide a means of optimising the design of such cavities for maintaining a safe environment for critical parts, such as disc rims and blade fixings, whilst maximising the turbine efficiency, and minimising the fuel burn and emissions penalties associated with the secondary airflow system. The modelling methods employed have been validated against data gathered from a dedicated two-stage turbine rig, running at engine representative conditions. Extensive measurements are available for a range of flow conditions and alternative cooling arrangements. The analysis method has been used to inform a design change which is also to be tested. Comparisons are provided between the predictions and measurements of the turbine stator well component temperature.

Experimental Investigation of Conjugate Heat Transfer in a Rib-Roughened Trailing Edge Channel With Crossing Jets

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Filippo Coletti ◽  
Manfredi Scialanga ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Outer Side ◽  
Uniform Heat Flux ◽  
Trailing Edge ◽  
Present Contribution ◽  
Element Analysis ◽  
Turbine Blade Cooling ◽  
The Impact ◽  
Rib Roughened

The present contribution is devoted to the experimental study of the conjugate heat transfer in a turbine blade cooling cavity located near the trailing edge. The cooling scheme is characterized by a trapezoidal cross-section, one rib-roughened wall, and slots along two opposite walls. The Reynolds number, defined at the inlet of the test section, is set at 67,500 for all the experiments. The values of all the important nondimensional parameters characterizing the experiment, including the solid-to-fluid conductivity ratio, are engine-representative. Uniform heat flux is imposed along the outer side of the rib-roughened wall. The measurements are performed using three different ribbed walls, with thermal conductivities ranging from 1 W m−1 K−1 to 18 W m−1 K−1. Highly resolved distributions of nondimensional temperature and Nusselt number over the rib-roughened wall are obtained by means of infrared thermography and finite element analysis. The impact of the conduction through the wall on the thermal performance is demonstrated by comparison with purely convective results, previously published by the authors on the same configuration.

Turbine Stator Well Cooling: Improved Geometry Benefits

2015 ◽  
Author(s):  
Julien Pohl ◽  
Jeffrey A. Dixon ◽  
Vincenzo Fico
Keyword(s):  
Experimental Data ◽  
Engine Performance ◽  
Prediction Method ◽  
Internal Flow ◽  
Element Analysis ◽  
Turbine Stator ◽  
Structured Mesh ◽  
Deflector Plate ◽  
Side Flow ◽  
Block Structured

Nowadays, it is common practice to expose engine components to air temperatures exceeding the thermal material limit in order to increase the overall engine performance and to minimise the engine specific fuel consumption (SFC). To avoid the overheating of the materials and thus the reduction of the component life, an internal flow system is designed to cool the critical engine parts and to protect them. As the coolant flow is bled from the compressor and not used for the combustion the amount of coolant is aimed to be minimised as much as possible to preserve the overall engine performance. Experiments as well as numerical simulations have shown that with the use of a deflector plate, the cooling flow is fed more directly into the disc boundary layer, allowing more effective use of less cooling air, leading to an improved engine efficiency. In this paper, the benefits of the use of a stationary deflector plate inside a turbine stator well (TSW) are presented. So far unpublished experimental data obtained from tests carried out in a two-stage turbine rig are presented. The main objective of this research has been to produce reliable methods for predicting the effects of geometry changes in this type of engine cavity, with a view to optimising the cooling flows required to maintain component integrity and life. Therefore, a numerical methodology is presented and validated against the experimental data. Steady and unsteady computational fluid dynamics (CFD) calculations of a sector model are used to determine whether fluid side flow distributions and heat transfer can be adequately represented, as well as to expose the limits of these approaches. The main annulus geometry is meshed with a multi-block structured mesh using the in-house code PADRAM. The cavity geometry is meshed once with a multi-block structured mesh using the commercial tool ANSYS ICEM and once with an unstructured mesh using the in-house code PADRAM. The CFD calculations are carried out with the commercial code FLUENT from ANSYS as well as the in-house code HYDRA. Finally, for the cavity with the deflector plate and no net ingestion, the steady state solution of the CFD is coupled to a finite element analysis (FEA) model created in the in-house code SC03 in order to take the conjugate effects into account. With this method the final non-adiabatic flow field inside the cavity as well as the final metal temperatures are obtained, which again are compared against thermocouple measured data in order to evaluate the accuracy of the numerical prediction method.

scholarly journals Analysis of Impact Energy to Fracture Unnotched Charpy Specimens Made From Railroad Tank Car Steel

2007 ◽  
Author(s):  
H. Yu ◽  
D. Y. Jeong ◽  
J. E. Gordon ◽  
Y. H. Tang
Keyword(s):  
Test Data ◽  
Impact Energy ◽  
Stress Triaxiality ◽  
Fracture Initiation ◽  
Equivalent Strain ◽  
Strain Criterion ◽  
Element Analysis ◽  
Damage And Failure ◽  
Failure Modeling ◽  
The Impact

This paper describes a nonlinear finite element analysis (FEA) framework that examines the impact energy to fracture unnotched Charpy specimens by an oversized, nonstandard pendulum impactor called the Bulk Fracture Charpy Machine (BFCM). The specimens are made from railroad tank car steel, have different thicknesses and interact with impact tups with different sharpness. The FEA employs a Ramberg-Osgood equation for plastic deformations. Progressive damage and failure modeling is applied to predict initiation and evolution of fracture and ultimate material failure. Two types of fracture initiation criterion, i.e., the constant equivalent strain criterion and the stress triaxiality dependent equivalent strain criterion, are compared in material modeling. The impact energy needed to fracture a BFCM specimen is calculated from the FEA. Comparisons with the test data show that the FEA results obtained using the stress triaxiality dependent fracture criterion are in excellent agreement with the BFCM test data.

Comparison of Heat Input Methods in Welding Residual Stress Analysis

2012 ◽  
Author(s):  
David J. Dewees
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Unit Length ◽  
Gaussian Function ◽  
Welding Residual Stress ◽  
Transfer Model ◽  
Element Analysis ◽  
Heat Transfer Modeling ◽  
Modeling Strategy ◽  
The Impact

Welding residual stress simulation through finite element analysis is becoming increasingly common in fitness-for-service (FFS) assessments of pressurized equipment. The driving force for the residual stress is non-uniform thermal expansion and plastic strain due to drastic temperature gradients; with this in mind, proper heat transfer modeling is essential to meaningful mechanical predictions. The fundamental input to the heat transfer model is the welding arc power, which is commonly represented as an assigned triple Gaussian function (Goldak double ellipsoid model) or more simply, as a uniform temperature. These two methods are compared in detail, and conclusions drawn about the impact of the heat transfer modeling strategy on the predicted weld residual stress for two detailed cases. This evaluation finds particular significance when the welding power, or more particularly the welding energy per unit length, is used in an attempt to characterize a given weld.

Design and Optimization of the Internal Cooling Channels of a HP Turbine Blade: Part I—Methodology

2008 ◽  
Author(s):  
Sergio Amaral ◽  
Tom Verstraete ◽  
Rene´ Van den Braembussche ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Turbine Blade ◽  
Turbine Rotor ◽  
Inlet Temperature ◽  
Analysis Tool ◽  
Internal Cooling ◽  
Element Analysis ◽  
Cooling Channels ◽  
The Impact

This first paper describes the Conjugate Heat Transfer (CHT) method and its application to the performance and lifetime prediction of a high pressure turbine blade operating at a very high inlet temperature. It is the analysis tool for the aerothermal optimization described in a second paper. The CHT method uses three separate solvers: a Navier-Stokes (NS) solver to predict the non-adiabatic external flow and heat flux, a Finite Element Analysis (FEA) to compute the heat conduction and stress within the solid, and a 1D aero-thermal model based on friction and heat transfer correlations for smooth and rib-roughened cooling channels. Special attention is given to the boundary conditions linking these solvers and to the stability of the complete CHT calculation procedure. The Larson-Miller parameter model is used to determine the creep-to-rupture failure lifetime of the blade. This model requires both the temperature and thermal stress inside the blade, calculated by the CHT and FEA. The CHT method is validated on two test cases: a gas turbine rotor blade without cooling and one with 5 cooling channels evenly distributed along the camber line. The metal temperature and thermal stress distribution in both blades are presented and the impact of the cooling channel geometry on lifetime is discussed.

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