A Hybrid Coupling Scheme and Stability Analysis for Coupled Solid/Fluid Turbine Blade Temperature Calculations

1998 ◽  
Author(s):  
Andreas Heselhaus
Keyword(s):  
Heat Conduction ◽  
Steady State ◽  
Turbine Blade ◽  
Gas Flow ◽  
Guide Vane ◽  
Thermal Design ◽  
Navier Stokes ◽  
Coupling Scheme ◽  
Flow Solver ◽  
Turbine Blade Cooling

Efficient thermal design of turbine blade cooling needs to take wall temperature effects on heat transfer into account. This can only be achieved by a coupled calculation of hot gas flow and blade heat conduction. In this paper principle and stability proof of an algorithm are presented that allows to couple a steady state finite element heat conduction solver with a blockstructured steady state finite volume (FV) Navier-Stokes time marching flow solver. The stability of the developed coupling procedure as well as the instability of an alternative algorithm is shown analytically and numerically. The benefits of coupled calculating are shown for a convectively cooled turbine guide vane blade. In the example treated, temperature differences of more than 100 K arise compared to the same calculation performed in an uncoupled way.

Using CFD to Reduce Resonant Stresses on a Single-Stage, High-Pressure Turbine Blade

2002 ◽  
Author(s):  
J. P. Clark ◽  
A. S. Aggarwala ◽  
M. A. Velonis ◽  
R. E. Gacek ◽  
S. S. Magge ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Guide Vane ◽  
Turbine Blades ◽  
Suction Side ◽  
Lessons Learned ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Time Resolved

The ability to predict levels of unsteady forcing on high-pressure turbine blades is critical to avoid high-cycle fatigue failures. In this study, 3D time-resolved computational fluid dynamics is used within the design cycle to predict accurately the levels of unsteady forcing on a single-stage high-pressure turbine blade. Further, nozzle-guide-vane geometry changes including asymmetric circumferential spacing and suction-side modification are considered and rigorously analyzed to reduce levels of unsteady blade forcing. The latter is ultimately implemented in a development engine, and it is shown successfully to reduce resonant stresses on the blade. This investigation builds upon data that was recently obtained in a full-scale, transonic turbine rig to validate a Reynolds-Averaged Navier-Stokes (RANS) flow solver for the prediction of both the magnitude and phase of unsteady forcing in a single-stage HPT and the lessons learned in that study.

Parametric Study of a Turbine Blade Cascade Using a New Parametric Flow Solver Turb’Opty

2002 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
M. N’Diaye ◽  
P. Ferrand ◽  
J. Tournier ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Stokes Equations ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Reference Solution ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Blade Cascade ◽  
Polynomial Reconstruction ◽  
Derivatives Of

A new parameterized CFD solver Turb’Opty™ has been developed based on a Taylor series expansion to high order derivatives of the solutions of the discretized Navier-Stokes equations. The method has been successfully applied to the laminar compressible flow field of the T106 turbine blade cascade. Comparisons with the classical CFD results have validated the accuracy of the parameterized solutions obtained by a simple polynomial reconstruction around a reference solution. The CPU efficiency has been emphasized by quickly computing the performance maps (power and losses) of this blade cascade. Wide industrial perspectives of turbomachinery global optimization are finally demonstrated by coupling this method with a simple genetic algorithm.

Conjugate Heat Transfer Enhancement of an Internal Blade Pin-Finned Tip-Wall

2009 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Conjugate Heat Transfer ◽  
Gas Flow ◽  
Turbine Blades ◽  
Thermal Design ◽  
Inlet Temperature ◽  
Computational Domain ◽  
Pin Fins ◽  
Blade Tip

To improve gas turbine performance, the operating temperature has been increased continuously. However, the heat transferred to the turbine blade is substantially increased as the turbine inlet temperature is increased. Cooling methods are therefore needed for the turbine blades to ensure a long durability and safe operation. The blade tip region is exposed to the hot gas flow and is difficult to cool. A common way to cool the tip is to use serpentine passages with 180-deg turn under the blade tip-cap taking advantage of the three-dimensional turning effect and impingement. Increasing internal convective cooling is therefore required to increase the blade tip life. In this paper, augmented heat transfer of a blade tip with internal pin-fins has been investigated numerically using a conjugate heat transfer approach. The computational model consists of a two-pass channel with 180-deg turn and an array of pin-fins mounted on the tip-cap. The computational domain includes the fluid region and the solid pins as well as the solid tip regions. Turbulent convective heat transfer between the fluid and pins, and heat conduction within pins and tip are simultaneously computed. The inlet Reynolds numbers are ranging from 100,000 to 600,000. Details of the 3D fluid flow and heat transfer over the tip surface are presented. A comparison of the overall performance of the two models is presented. It is found that due to the combination of turning impingement and pin-fin cross flow, the heat transfer coefficient of the pin-finned tip is a factor of about 3.0 higher than that of a smooth tip. This augmentation is achieved at the cost of a pressure drop penalty of about 7%. With the conjugate heat transfer method, not only the simulated model is close to the experimental model, but also the distribution of the external tip heat transfer can be relevant for thermal design of turbine blade tips.

scholarly journals The Influence of Rotation on the Internal Flow of a Cooled Turbine Blade With Serpentine-Shaped Cooling Channels

1997 ◽  
Author(s):  
Y. Otsuki ◽  
T. Sugimoto ◽  
R. Tanaka ◽  
D. E. Bonn ◽  
V. J. Becker ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Gas Flow ◽  
Stokes Equations ◽  
Internal Flow ◽  
Computer Code ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
3 Dimensional ◽  
Cooling Channels ◽  
Blade Cooling

Numerical 3-D investigations have been carried out in order to analyze the cooling gas flow pattern inside a turbine blade configuration. The blade is not an actual industrial configuration but is representative for contemporary configurations. The cooling gas enters the serpentine cooling channels through the blade foot. The cooling gas mass flow is divided into two serpentine flows. One covers the front part of the blade and is ejected at the tip, the other serves the rear region and is ejected through a slot in the trailing edge. Internal turbulence promoters are neglected. Boundary conditions typical for front stage blade cooling gas states were chosen. The computations have been performed with the modern CHTFlow computer code, which solves the fully compressible 3-dimensional Navier-Stokes equations. First the influence of the diffusive transport mechanisms is investigated and shown to be quite important. Through comparison of computation in a fixed and rotating frame of reference, the significant influence of rotation is demonstrated.

Turbine Blade Thermal Design Process Enhancements for Increased Firing Temperatures and Reduced Coolant Flow

2007 ◽  
Author(s):  
J. Kru¨ckels ◽  
T. Arzel ◽  
T. R. Kingston ◽  
M. Schnieder
Keyword(s):  
Turbine Blade ◽  
Design Process ◽  
New Technology ◽  
Three Dimensional ◽  
Element Model ◽  
Design Tool ◽  
Thermal Design ◽  
Successful Implementation ◽  
Analysis Tool ◽  
Turbine Blade Cooling

A successful implementation of a cooled turbine blade design for a heavy duty gas turbine engine is a technology challenge that requires a stringent engineering approach. The increased spread of hot gas versus metal temperature, the flatter temperature profiles for reduced emissions and the aerodynamic 3D-profile shape requirement and all at a reduced cooling air consumption place the specification of a new turbine blade, that is put forward to the aerothermal engineers, as a technical challenge. It is also desired to reduce the available development time to be able to introduce new technology features faster into the market. The paper aims to demonstrate turbine blade cooling and heat transfer design process enhancements that allow: increased thermal predictability, increased capturing of three dimensional effects and reduced engineering development cycle time from initial design to full engine validation. Selected items will be shown for demonstration. One example is the use of symmetry and parameterization to move CFD from an analysis tool into an available design tool to capture effects as rotation or three-dimensionality. Another example is the use of heat sinks within a finite element model to represent individual cooling holes instead of hole geometry.

A Gas Turbine Blade Thermal/Structural Program With Linked Flow-Solid Modeling Capability

1994 ◽  
Author(s):  
S. M. Wan ◽  
T. C. T. Lam ◽  
J. M. Allen ◽  
T. H. McCloskey
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Flow ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Solid Modeling ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Gas Turbine Blade

A time-marching approach is adopted in developing a thermal/structural program with linked flow-solid modeling capability. The Blade Life Analysis & Design Evaluation for Combustion Turbines (BLADE-CT) program analyzes gas turbine blade thermal-mechanical stress and natural frequencies under the boundary conditions which result from the gas flow and the cooling/barrier flow within a given turbine stage. Using the finite element method, the blade temperatures obtained from transient/steady-state thermal solutions can be utilized to compute thermal stresses and dynamic stresses under operating conditions for assessing thermal-mechanical fatigue damage in combustion turbine blades. A customized and automated mesh generation routine is developed to model cooled (spanwise multihole configurations) and solid gas turbine blades. By coupling the NASA flow programs, PCPANEL (potential flow), STAN5 (heat transfer boundary layer), and CPF (coolant passage flow) as part of an automated flow-structural analysis approach, a more efficient and accurate thermal and thermal stress calculation can be achieved. The calculated blade temperatures can be also applied for the frequency analysis to account for temperature effects. The coupled fluid-structure interaction program approach for thermal-mechanical analysis and an example of a spanwise cooled blade steady state analysis are presented.

scholarly journals Experimental and Numerical Investigations of the Aerodynamical Effects of Coolant Injection Through the Trailing Edge of a Guide Vane

1995 ◽  
Author(s):  
Dieter E. Bohn ◽  
Volker J. Becker ◽  
Klaus D. Behnke ◽  
Bernhard F. Bonhoff
Keyword(s):  
Gas Turbines ◽  
Guide Vane ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Hot Gas ◽  
Flow Situation ◽  
Circumferential Distribution ◽  
Volume Method

Effective turbine blade cooling is necessary to enhance the efficiency of gas turbines. Usually the coolant is mainly ejected through the trailing edge of the vanes. In addition to the desired temperature reduction at the trailing edge there is a 3D-aerodynamical interaction between the hot gas and the coolant. The complex mechanisms of the mixture are a main problem in the numerical prediction of the flow situation in this region. This paper presents the experimental and numerical results of investigations of annular guide vanes. The experiments were conducted in a scaled turbine test rig. The mixing flow of coolant and hot gas was analyzed by measurement of the distribution of both velocity and turbulence very close to the trailing edge using a 2D-LDA measurement technique at different radial positions. The experimental results show that the radial and circumferential distribution of the coolant depends on the pressure gradient in both directions. Inside of the mixture region the turbulence was found to be anisotropic resulting in a non-symmetrical distribution of the coolant. For the numerical calculations a Navier-Stokes-Code was used. The numerical scheme works on the basis of an implicit finite volume method combined with a multi block technique. In order to simulate the aerodynamical effects near the injection slot of the vane it was nessessary to include the coolant flow inside the guide vane.

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