Thermo Mechanical Optimization of Cooled Turbine Vane

2007 ◽  
Author(s):  
Grzegorz Nowak ◽  
Włodzimierz Wro´blewski
Keyword(s):  
Cooling System ◽  
System Optimization ◽  
Internal Cooling ◽  
Thermal Boundary Conditions ◽  
Optimization Task ◽  
Turbine Vane ◽  
External Conditions ◽  
Mechanical Optimization ◽  
Cooling Air ◽  
Material Temperature

This paper discuses the problem of cooling system optimization within a gas turbine vane regarding to thermo-mechanical behaviour of the component. The analysis involves the optimization of location and size of internal cooling passages within the vane. Cooling is provided with ten circular passages and heat is transported by convection. The task is approached in 3D configuration. Each passage is fed with cooling air of constant parameters at the inlet. Also a constant pressure drop is assumed along the passage length. The thermal boundary conditions in passages varied with diameter and local vane temperature (passage wall temperature). The analysis is performed by means of the genetic algorithm for the optimization task and FEM for the heat transfer predictions within the component. In the present study the vane profile is taken as aerodynamically optimal and the objective of the search procedure is to find cooling structure variant that at given external conditions provides possibly low stresses and material temperature.

Multidisciplinary Optimization of Airfoil Cooling Structure

2008 ◽  
Author(s):  
Grzegorz Nowak
Keyword(s):  
Cooling System ◽  
Computational Cost ◽  
System Optimization ◽  
Multidisciplinary Optimization ◽  
Internal Cooling ◽  
Technical Problems ◽  
Thermal Boundary Conditions ◽  
Optimization Task ◽  
External Conditions ◽  
Cooling Air

This paper discusses the problem of cooling system optimization within a gas turbine airfoil regarding to thermo-mechanical behavior of the component, as well as some economical aspects of turbine operation. The main goal of this paper is to show the possibilities of evolutionary approach application to the cooling system optimization. This method, despite its relatively high computational cost, seems to be a valuable tool to such technical problems. The analysis involves the optimization of location and size of internal cooling passages within an airfoil. Initially cooling is provided with circular passages and heat is transported by convection. During the optimization the number of channels can vary. The task is approached in 3D configuration. Each passage is fed with cooling air of constant parameters at the inlet. Also a constant pressure drop is assumed along the passage length. The thermal boundary conditions in passages vary with diameter and local vane temperature (passage wall temperature). The analysis is performed by means of the genetic algorithm for the optimization task and FEM for the heat transfer predictions within the component. In the present study the airfoil profile is taken as aerodynamically optimal and the objective of the search procedure is to find cooling structure variant that at given external conditions provides lower stresses, material temperature and indirectly coolant usage.

Application of Conjugate Heat Transfer for Cooling Optimization of a Turbine Airfoil

2009 ◽  
Author(s):  
Grzegorz Nowak ◽  
Włodzimierz Wro´blewski
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Thermal Field ◽  
Cooling System ◽  
Solid Material ◽  
System Optimization ◽  
Point Of View ◽  
Internal Cooling ◽  
Cooling Channels ◽  
Cooling Air

This paper discusses the problem of airfoil cooling system optimization connected with Conjugate Heat Transfer (CHT) analysis for reliable thermal field prediction within a cooled component. Since the full CHT solution, which involves the main flow, blade material and the coolant flow domains is computationally expensive from the point of view of optimization process, it was decided to reduce the problem by fixing the boundary conditions at the blade surface and solving the task for the interior only (both solid material and coolant). Such assumption, on one hand, makes the problem computationally feasible, and on the other, provides more reliable thermal field prediction than it used to be with the empirical relationships. The analysis involves the optimization of location and size of internal cooling passages within an airfoil. Initially, cooling is provided with circular passages and heat is transported by convection. The task is approached in 3D configuration. Each passage is fed with cooling air of constant parameters at the inlet. In the present study the airfoil profile is taken as aerodynamically optimal. The optimization is done with an evolutionary algorithm within a 30 dimensional design space, composed of space coordinates and radii of cooling channels. The search is realized with a weighted single objective function, which consisted of three objectives formulated on the basis of the airfoil’s thermal field and coolant mass flow.

Alstom GT11N2 M Expansion Turbine Design Modification and Operation Experience

2009 ◽  
Author(s):  
Sergey Vorontsov ◽  
Stefan Irmisch ◽  
Alexey Karelin ◽  
Marcelo Rocha
Keyword(s):  
Gas Turbines ◽  
Cooling System ◽  
Engine Performance ◽  
System Optimization ◽  
Interval Length ◽  
Gas Temperature ◽  
Design Modification ◽  
Expansion Turbine ◽  
Efficiency Increase ◽  
Cooling Air

This paper summarizes the development steps and measures taken for the upgrade of the GT11N2 Turbine. The main targets to be achieved were specified as follows: - GT power increase; - GT gross efficiency increase; - Flexible operation with respect to power output and service interval length. All 4 turbine stages were re-designed in order to optimize their aerodynamic performance and minimize cooling air consumption. Turbine aerodynamic efficiency improvement was achieved by means of: - Turbine stage-to-stage loading optimization; - 3D airfoil profiling; - Replacement of the damping bolt of blade 4 by a full shroud; - Stator/rotor sealing optimization. On top of that, cooling air consumption was reduced by means of cooling system optimization for Vane 1, Blade 1, Vane 2, Blade2 and SHS/A. This allowed an increase of TIT (inlet turbine mixed temperature) keeping the hot gas temperature at the turbine inlet unchanged, which is important for meeting lifetime and emission targets. One of the key requirements for this Turbine Upgrade was to use exclusively validated design approaches and design features as available from existing and proven Alstom Gas Turbines ([1], [2], [3]) in order to minimize development- and implementation risks. Manufacturing of the new turbine parts was completed in an exceptionally short time, thanks to a dedicated R&D Logistic and Manufacturing support/process, an efficient NCR (Non Conformance Report) process, early supplier involvement and a very close/open work with suppliers. The first prototype of this turbine was implemented in a GT11N2 customer engine. Performance validation runs, performed in May 2008 confirmed that the design targets for power and efficiency were fully met. The validation of the turbine parts lifetime is still ongoing.

Influence of Coolant on Cooling Performance Sensitivity of Internally Convective Turbine Vane

2021 ◽  
Author(s):  
Thanapat Chotroongruang ◽  
Prasert Prapamonthon ◽  
Rungsimun Thongdee ◽  
Thanapat Thongmuenwaiyathon ◽  
Zhenxu Sun ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Film Cooling ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Turbine Engine ◽  
Performance Sensitivity ◽  
Turbine Vane ◽  
Cooling Air

Abstract Based on the Brayton cycle for gas-turbine engines, the high thermal efficiency and power output of a gas-turbine engine can be obtainable when the gas-turbine engine operates at high turbine inlet temperatures. However, turbine components e.g., inlet guide vane, rotor blade, and stator vane request high cooling performance. Typically, internal cooling and film cooling are two effective techniques that are widely used to protect high thermal loads for the turbine components in a state-of-the-art gas turbine. Consequently, the high thermal efficiency and power output can be obtained, and the turbine lifespan can be prolonged, also. On top of that, a comprehensive understanding of flow and heat transfer phenomena in the turbine components is very important. As a result, both experiments and simulations have been used to improve the cooling performance of the turbine components. In fact, the cooling air used in the internal cooling and film cooling is partially extracted from the compressor. Therefore, variations in the cooling air affect the cooling performance of the turbine components directly. This paper presents a numerical study on the influence of the cooling air on cooling-performance sensitivity of an internally convective turbine vane, MARK II using the computational fluid dynamics (CFD)/conjugate heat transfer (CHT) with the SST k-ω turbulence model. Result comparisons are conducted in terms of pressure, temperature, and cooling effectiveness under the effects of the inlet temperature, mass flow rate, turbulence intensity, and flow direction of the cooling air. The cooling-performance sensitivity to the coolant parameters is shown through variations of local cooling effectiveness, and area and volume-weighted average cooling effectiveness.

Effusion Cooling System Optimization for Modern Lean Burn Combustor

2016 ◽  
Author(s):  
Antonio Andreini ◽  
Riccardo Becchi ◽  
Bruno Facchini ◽  
Lorenzo Mazzei ◽  
Alessio Picchi ◽  
...  
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Heat Removal ◽  
System Optimization ◽  
Field Investigation ◽  
Metal Temperature ◽  
Back Side ◽  
Lean Burn ◽  
Standard Configuration ◽  
Cooling Air

Stricter legislation limits concerning NOx emissions are leading main aero-engine manufacturers to update the architecture of the combustors towards the implementation of lean burn combustion concept. Cooling air availability for the thermal management of combustor liners is significantly reduced, demanding even more effective liner cooling schemes. The state-of-the-art of liner cooling technology is represented by effusion cooling, consisting in a very efficient cooling strategy based on multi-perforated liners, where metal temperature is lowered by the combined protective effect of coolant film and heat removal inside the holes. The present research study aims at deepening the knowledge of effusion systems, exploiting the results of a thorough experimental campaign carried out in two different planar test rigs, equipped with a complete liner cooling scheme composed by slot injection and effusion array. The film cooling protection was analysed using PSP (Pressure Sensitive Paint) technique, while the effect of cooling injection and extraction from the annulus on heat transfer distribution were studied by means of TLC (Thermochromic Liquid Crystals) thermography. Thermal measurements were supported by flow field investigation with standard 2D PIV (Particle Image Velocimetry) in order to highlight the typical velocity distributions generated by a realistic lean injector. These detailed experimental data were exploited in a 1D thermal flow-network solver that allows to better assess the main cooling mechanisms characterising the proposed cooling system. Moreover, an optimized cooling configuration with enhanced back-side convective cooling was proposed and compared with the standard configuration in terms of metal temperature and cooling consumption.

Investigation of Internal Cooling Air Flow of Gas Turbines With Attention to Heat Transfer

2003 ◽  
Author(s):  
D. Brillert ◽  
F.-K. Benra ◽  
H. J. Dohmen ◽  
O. Schneider
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Flow Physics ◽  
Cooling Flow ◽  
Air System ◽  
Secondary Air ◽  
Cooling Air ◽  
Material Temperature

The cooling air in the secondary air system of gas turbines is routed through the inside of the rotor shaft. The air enters the rotor through an internal extraction in the compressor section and flows through different components to the turbine blades. Constant improvements of the secondary air system is a basic element to increase efficiency and power of heavy duty gas turbines. It is becoming more and more important to have a precise calculation of the heat transfer and air temperature in the internal cooling air system. This influences the cooling behavior, the material temperature and consequently the cooling efficiency. The material temperature influences the stresses and the creep behavior which is important for the life time prediction and the reliability of the components of the engine. Furthermore, the material temperature influences the clearances and again the cooling flow, e.g. the amount of mass flow rate, hot gas ingestion etc. This paper deals with an investigation of the influence of heat transfer on the internal cooling air system and on the material temperature. It shows a comparison between numerical calculations with and without heat transfer. Firstly, the Navier-Stokes CFD calculation shows the cooling flow physics of different parts of the secondary air system passages with solid heat transfer. In the second approach, the study is expanded to consider the cooling flow physics under conditions without heat transfer. On the basis of these investigations, the paper shows a comparison between the flow with and without heat transfer. The results of the simulation with heat transfer show a negligible influence on the cooling flow temperature and a stronger influence on the material temperature. The results of the calculations are compared with measured data. The influence on the material temperature is verified with measured material temperatures from a Siemens Model V84.3A gas turbine prototype.

Application of Conjugate CFD to the Internal Cooling Air Flow System of Gas Turbines

2003 ◽  
Author(s):  
D. Brillert ◽  
H. J. Dohmen ◽  
F.-K. Benra ◽  
O. Schneider ◽  
A. V. Mirzamoghadam
Keyword(s):  
Heat Transfer ◽  
Thermal Effects ◽  
Gas Turbines ◽  
Air Flow ◽  
Jet Flow ◽  
Calculation Procedure ◽  
Internal Cooling ◽  
Cooling Air Flow ◽  
Cooling Air ◽  
Material Temperature

Continuous improvements of the secondary air system are basic elements to increase efficiency and power of heavy duty gas turbines. It is becoming more important to perform a precise calculation of the heat transfer characteristics and to produce accurate predictions of the air/metal temperature in the internal cooling air system. Thermal effects influences the cooling behavior and consequently the cooling efficiency and the material temperature. The material temperature influences the stresses and the creep behavior that is important for life prediction and the reliability of the engine. Furthermore, the material temperature influences the clearances and therefore, the cooling mass-flow. This paper deals with a complex internal blade feed system comprising a forced radially-inward jet-flow into a large rotating cavity and the numerical coupling of different cooling air flow passages with component heat transfer, i.e. conjugate CFD. A calculation procedure was adopted to reproduce the measured rotating main shaft temperatures from the Siemens Model V84.3A gas turbine prototype. Based on this procedure, flow and heat transfer throughout the sub-cavities were discussed and the shaft temperature distribution was obtained. Results indicate a strong interaction between the thermal effects of the cooler radial jet-flow and the hotter seal gap regions. Moreover, the deficiencies in the adopted calculation procedure were identified.

Optimization of Cooling Passages Within a Turbine Vane

2005 ◽  
Author(s):  
Grzegorz Nowak ◽  
Włodzimierz Wro´blewski ◽  
Tadeusz Chmielniak
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Cooling System ◽  
Negative Effects ◽  
Optimization Task ◽  
Turbine Performance ◽  
Turbine Vanes ◽  
Turbine Vane ◽  
Internally Cooled ◽  
High Temperature Components

The trends in gas turbine technology aim to build more and more efficient cycles, which is usually achieved by the temperature increase at the inlet of the turbine. To prevent the negative effects of elevated temperature some actions are taken concerning, among others cooling of the high temperature components. Since the structure of the cooling system affects the turbine performance, it is essential to carry out the optimization to make it as efficient as possible. In this paper we show some aspects of passage optimization for internally cooled gas turbine vanes. In the present study the vane profile is taken as aerodynamically optimal. The analysis involves the optimization of the location and size of circular cooling passages within the vane. The analysis is performed by means of the genetic algorithm for the optimization task and FEM for the heat transfer predictions within the blade.

scholarly journals Turbine Blade Cooling System Optimization

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Julian Girardeau ◽  
Jérôme Pailhes ◽  
Patrick Sebastian ◽  
Frédéric Pardo ◽  
Jean-Pierre Nadeau
Keyword(s):  
Gas Turbine ◽  
High Performance ◽  
Cooling System ◽  
System Optimization ◽  
Internal Cooling ◽  
Cooling Systems ◽  
Turbine Blade Cooling ◽  
Turbine Vanes ◽  
Low Efficiency ◽  
Aerodynamic Losses

Designing high performance cooling systems suitable for preserving the service lifetime of nozzle guide vanes of turboshaft engines leads to significant aerodynamic losses. These losses jeopardize the performance of the whole engine. In the same time, a low efficiency cooling system may affect the costs of maintenance repair and overhaul of the engine as component life decreases. Consequently, designing cooling systems of gas turbine vanes is related to a multiobjective design problem. In this paper, it is addressed by investigating the functioning of a blade and optimizing its design by means of an evolutionary algorithm. Systematic 3D CFD simulations are performed to solve the aero-thermal problem. Then, the initial multiobjective problem is solved by aggregating the multiple design objectives into one single relevant and balanced mono-objective function; two different types of mono-objective functions are proposed and compared. This paper also proposes to enhance available knowledge in the literature of cooling systems of gas turbine vanes by simulating the internal cooling system of the vane. From simulations thermal efficiency and aerodynamic losses are compared and their respective influences on the global performances of the whole engine are investigated. Finally, several optimal designs are proposed.

scholarly journals Application of evaluationary approach to thermo-mechanical optimization of gas turbine airfoil cooling configuration

2010 ◽  
Vol 31 (2) ◽  
pp. 3-20
Author(s):  
Grzegorz Nowak
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Evolutionary Approach ◽  
Cylindrical Shape ◽  
Internal Cooling ◽  
Operation Condition ◽  
Reference Case ◽  
Positive Effects ◽  
Mechanical Optimization

Application of evaluationary approach to thermo-mechanical optimization of gas turbine airfoil cooling configurationCooling of the hot gas path components plays a key role in modern gas turbines. It allows, due to efficiency reasons, to operate the machines with temperature exceeding components' melting point. The cooling system however brings about some disadvantages as well. If so, we need to enforce the positive effects of cooling and diminish the drawbacks, which influence the reliability of components and the whole machine. To solve such a task we have to perform an optimization which makes it possible to reach the desired goal. The task is approached in the 3D configuration. The search process is performed by means of the evolutionary approach with floatingpoint representation of design variables. Each cooling structure candidate is evaluated on the basis of thermo-mechanical FEM computations done with Ansys via automatically generated script file. These computations are parallelized. The results are compared with the reference case which is the C3X airfoil and they show a potential stored in the cooling system. Appropriate passage distribution makes it possible to improve the operation condition for highly loaded components. Application of evolutionary approach, although most suitable for such problems, is time consuming, so more advanced approach (Conjugate Heat Transfer) requires huge computational power. The analysis is based on original procedure which involves optimization of size and location of internal cooling passages of cylindrical shape within the airfoil. All the channels can freely move within the airfoil cross section and also their number can change. Such a procedure is original.

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