Heat Transfer Computations for High Pressure Turbines

2001 ◽  
Author(s):  
Graham C. Smith ◽  
Mary A. Hilditch ◽  
Nigel B. Wood
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Cooling System ◽  
Operating Temperature ◽  
Test Facility ◽  
Navier Stokes ◽  
Major Influence ◽  
High Pressure Turbine ◽  
Turbulent Transition ◽  
Very High

The life of a high pressure turbine blade is strongly dependent on the operating temperature of the blade material. The gas entering the turbine is at a very high temperature and the blades must be cooled. Accurate predictions of the heat transfer to an uncooled aerofoil are an important step in predicting the blade metal temperature and designing an efficient cooling system. 3D Navier-Stokes calculations of heat transfer are presented for the vanes of two modern high pressure, shroudless turbines. The results are compared with measurements taken in a short duration test facility at engine representative conditions. The experimental dataset includes repeat measurements made using different instrumentation. These data are shown to agree within the confidence limits of the experiment. In this experiment laminar-turbulent transition is known to be a major influence on the measured heat transfer levels. However, careful modelling of this parameter, through physical reasoning and published correlations, gives predictions in reasonable agreement with the measurements.

Assessment of the Impact of Laminar-Turbulent Transition on the Accuracy of Heat Transfer Coefficient Prediction in High Pressure Turbines

2006 ◽  
Author(s):  
Mahmoud L. Mansour ◽  
Khosro Molla Hosseini ◽  
Jong S. Liu ◽  
Shraman Goswami
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
High Pressure ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Test Cases ◽  
Turbine Cascade ◽  
High Pressure Turbine ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

This paper presents a thorough assessment for two of the contemporary CFD programs available for modeling and predicting nonfilm-cooled surface heat transfer distributions on turbine airfoil surfaces. The CFD programs are capable of predicting laminar-turbulent transition and have been evaluated and validated against five test cases with experimental data. The suite of test cases considered for this study consists of two flat plat cases at zero and non-zero pressure gradient and three linear-turbine-cascade test cases that are representative of modern high pressure turbine designs. The flat plate test cases are the ERCOFTAC T3A and T3C2, while the linear turbine cascade cases are the MARKII, the Virginia Polytechnic Institute (VPI), and the Von Karman Institute (VKI) turbine cascades. The numerical tools assessed in this study are 3D viscous Reynolds Averaged-Navier-Stokes (RANS) equations programs that employ a variety of one-equation and two-equation models for turbulence closure. The assessment study focuses on the one-equation Spalart and Allmaras and the two-equation shear stress transport K-ω turbulence models with the ability of modeling and predicting laminar-turbulent transition. The RANS 3D viscous codes are Numeca’s Fine Turbo and ANSYS-CFX’ CFX5. Numerical results for skin friction, surface temperature distribution and heat transfer coefficient from the CFD programs are compared to measured experimental data. Sensitivity of the predictions to free stream turbulence and to inlet turbulence boundary conditions is also presented. The results of the study clearly illustrate the superiority of using the laminar-turbulent transition prediction in improving the accuracy of predicting the heat transfer coefficient on the surfaces of high pressure turbine airfoils.

scholarly journals Calculation and Correlation of the Unsteady Flowfield in a High Pressure Turbine

2002 ◽  
Author(s):  
Milind A. Bakhle ◽  
Jong S. Liu ◽  
Josef Panovsky ◽  
Theo G. Keith ◽  
Oral Mehmed
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Turbine Stage ◽  
High Pressure Turbine

Forced vibrations in turbomachinery components can cause blades to crack or fail due to high-cycle fatigue. Such forced response problems will become more pronounced in newer engines with higher pressure ratios and smaller axial gap between blade rows. An accurate numerical prediction of the unsteady aerodynamics phenomena that cause resonant forced vibrations is increasingly important to designers. Validation of the computational fluid dynamics (CFD) codes used to model the unsteady aerodynamic excitations is necessary before these codes can be used with confidence. Recently published benchmark data, including unsteady pressures and vibratory strains, for a high-pressure turbine stage makes such code validation possible. In the present work, a three dimensional, unsteady, multi blade-row, Reynolds-Averaged Navier Stokes code is applied to a turbine stage that was recently tested in a short duration test facility. Two configurations with three operating conditions corresponding to modes 2, 3, and 4 crossings on the Campbell diagram are analyzed. Unsteady pressures on the rotor surface are compared with data.

Endwall Effusion Cooling System Behaviour Within a High-Pressure Turbine Cascade: Part 2—Heat Transfer and Effectiveness Measurements

2010 ◽  
Author(s):  
B. Facchini ◽  
L. Tarchi ◽  
L. Toni ◽  
S. Zecchi
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Large Scale ◽  
Cooling System ◽  
Main Flow ◽  
Turbine Cascade ◽  
High Pressure Turbine ◽  
Cooling Flow ◽  
Micro Holes ◽  
Element Approach

The cooling performance of a micro-holed endwall of a large-scale high pressure turbine cascade has been investigated within the European Project AITEB-2. The experimental investigation has been performed for a baseline configuration, with a smooth solid endwall and with a micro-holed endwall providing micro-jets ejection from the wall. A micro-holed endwall made of two modules was adopted in order to reduce the compound angle between the main flow and the micro jets axes. The micro-holed endwall is provided with a total amount of 3294 micro-holes with a diameter of 0.1 per cent of the blade chord. Four different cooling flow rates, from 1.2% to 2.6% of the main flow mass flow rate respectively, were investigated and the experimental results are reported in the paper. Both adiabatic effectiveness and heat transfer coefficient have been measured employing a steady state technique with Thermo-chromic Liquid Crystals (TLC). A thin stainless steel heating foil was used to generate the surface heat flux for the HTC measurements and a data reduction procedure based on a Finite Element approach has been developed to take into account the non uniform heat generation along the endwall.

Development and Testing of the Upgraded High Pressure Turbine Section for an Industrial Gas Turbine

2008 ◽  
Author(s):  
E. Aschenbruck ◽  
D. Frank ◽  
T. Korte ◽  
R. Mu¨ller ◽  
U. Orth
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Cooling System ◽  
Mechanical Design ◽  
Development Program ◽  
Tip Clearance ◽  
Test Facility ◽  
High Pressure Turbine ◽  
Online Data ◽  
Clearance Control

As part of an ongoing development program to increase power output and efficiency of the THM 1304 gas turbine, modifications were made to the high pressure turbine. The modifications include but are not limited to blade and vane aerodynamics, cooling system and clearance control, mechanical design and materials. The development was to achieve the following goals: • Intensified blade and vane cooling to permit higher turbine inlet temperatures and to further extend service lifetime; • Improved aerodynamic performance; • Blades with pre-loaded tip shrouds to achieve low vibration amplitudes in a broad operating speed range; • Rotor design modifications to simplify assembly and disassembly; • Modified vane carrier and casing designs for optimal tip clearance control and turbine performance. The improved high pressure turbine was extensively tested in MAN TURBO’s full-load gas turbine test facility. Test results verified that component temperatures were within the expected range and design targets have been achieved. The first production gas turbine equipped with the upgraded high pressure turbine was installed in May 2004 as a gas compressor driver. To date a total of 11 units have gone into operation including units for power generation. Dry low emission technology is used on all engines. Every unit is monitored by an online data monitoring system and visually inspected in shorter intervals to verify the behavior in the field. Operation of the fleet is flawless at this time.

Heat Transfer Measurements and Predictions for a Modern, High-Pressure, Transonic Turbine, Including Endwalls

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
James A. Tallman ◽  
Charles W. Haldeman ◽  
Michael G. Dunn ◽  
Anil K. Tolpadi ◽  
Robert F. Bergholz
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Turbulence Modeling ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Local Measurements ◽  
Transonic Turbine ◽  
The Ohio State University

This paper presents both measurements and predictions of the hot-gas-side heat transfer to a modern, 112 stage high-pressure, transonic turbine. Comparisons of the predicted and measured heat transfer are presented for each airfoil at three locations, as well as on the various endwalls and rotor tip. The measurements were performed using the Ohio State University Gas Turbine Laboratory Test Facility (TTF). The research program utilized an uncooled turbine stage at a range of operating conditions representative of the engine: in terms of corrected speed, flow function, stage pressure ratio, and gas-to-metal temperature ratio. All three airfoils were heavily instrumented for both pressure and heat transfer measurements at multiple locations. A 3D, compressible, Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) solver with k-ω turbulence modeling was used for the CFD predictions. The entire 112 stage turbine was solved using a single computation, at two different Reynolds numbers. The CFD solutions were steady, with tangentially mass-averaged inlet/exit boundary condition profiles exchanged between adjacent airfoil-rows. Overall, the CFD heat transfer predictions compared very favorably with both the global operation of the turbine and with the local measurements of heat transfer. A discussion of the features of the turbine heat transfer distributions, and their association with the corresponding flow-physics, has been included.

Aerothermodynamics of a High-Pressure Turbine Blade With Very High Loading and Vortex Generators

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Reinaldo A. Gomes ◽  
Reinhard Niehuis
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Flow Separation ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
Suction Side ◽  
Vortex Generators ◽  
High Pressure Turbine ◽  
Very High

AITEB-2 is a project where aerothermal challenges of modern high pressure turbine designs are analyzed. One of the scopes of the project is to allow for new gas turbine designs with less parts and lighter jet engines by increasing the blade pitch and therefore the aerodynamic blade loading. For transonic profiles, this leads to very high velocities on the suction side and shock induced separation is likely to occur. The total pressure loss increase due to flow separation and strong shocks, as well as the underturning of the flow, limits the increase of the blade pitch. In this paper, experiments using a linear turbine blade cascade with high aerodynamic loading are presented. The blade pitch is increased such that at design conditions, a strong separation occurs on the suction side. The experiments were run at high subsonic exit Mach numbers and at Reynolds numbers of 390,000 and 800,000. In order to reduce the flow separation and the aerodynamic losses, air jet vortex generators are used, which create streamwise vortices prior to the separation start. Since in high pressure turbine blades film cooling is widely used, also the influence of film cooling both with and without using vortex generators is analyzed. Film cooling is provided on the suction side by two rows of cylindrical holes. This paper provides an analysis of the influence of different main flow conditions, film cooling, and vortex generators on total pressure loss, heat transfer and film cooling effectiveness. The experiments show that the vortex generators, as well as the film cooling reduce flow separation and total pressure losses. The effects are also seen in the local heat transfer, especially with enhanced heat transport in the region with flow separation. The cases presented in this paper deal with complex flow phenomena, which are challenging to be predicted with modern numerical tools correctly. Therefore, the experimental data serve as a comprehensive database for validation of simulation tools in the AITEB-2 project.

Aerothermodynamics of a High-Pressure Turbine Blade With Very High Loading and Vortex Generators

2010 ◽  
Author(s):  
Reinaldo A. Gomes ◽  
Reinhard Niehuis
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Flow Separation ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
Suction Side ◽  
Vortex Generators ◽  
High Pressure Turbine ◽  
Very High

AITEB-2 is a project where aerothermal challenges of modern high pressure turbine designs are analysed. One of the scopes of the project is to allow for new gas turbine designs with less parts and lighter jet engines by increasing the blade pitch and therefore the aerodynamic blade loading. For transonic profiles this leads to very high velocities on the suction side and shock induced separation is likely to occur. The total pressure loss increase due to flow separation and strong shocks as well as the under-turning of the flow limits the increase of the blade pitch. In this paper experiments using a linear turbine blade cascade with high aerodynamic loading are presented. The blade pitch is increased such that at design conditions a strong separation occurs on the suction side. The experiments were run at high subsonic exit Mach numbers and at Reynolds numbers of 390,000 and 800,000. In order to reduce the flow separation and the aerodynamic losses, air jet vortex generators are used which create streamwise vortices prior to the separation start. Since in high pressure turbine blades film cooling is widely used, also the influence of film cooling both with and without using vortex generators is analysed. Film cooling is provided on the suction side by two rows of cylindrical holes. The paper provides an analysis of the influence of different main flow conditions, film cooling and vortex generators on total pressure loss, heat transfer and film cooling effectiveness. The experiments show that the vortex generators as well as the film cooling reduce flow separation and total pressure losses. Effects are also seen in the local heat transfer, especially with enhanced heat transport in the region with flow separation. The cases presented in this paper deal with complex flow phenomena which are challenging to be predicted with modern numerical tools correctly. Therefore the experimental data serve as a comprehensive data base for CFD validation in the AITEB-2 project.

CFD Heat Transfer Predictions for a High-Pressure Turbine Stage

2004 ◽  
Author(s):  
James A. Tallman
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Turbulence Modeling ◽  
Pressure Ratio ◽  
Numerical Procedure ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Computational Fluid Dynamics Cfd

Computational Fluid Dynamics (CFD) was used to predict the turbine airfoil heat transfer for the high-pressure vane and high-pressure blade of a modern, one and one half stage turbine at its correct scale. Airfoil pressure and heat transfer measurements were recently obtained for the turbine in a transient shock tunnel facility, which allows for the replication of the actual engine turbine’s design corrected speed, pressure ratio, and gas-to-metal temperature ratio. A 3-D, compressible, Reynolds-averaged Navier-Stokes CFD solver with k-ω turbulence modeling was used for the CFD predictions. The turbulence model’s implementation into the numerical procedure was modified slightly, in order to better capture the model’s intended near-wall behavior and resolve the heat transfer prediction. Both the high-pressure vane and high-pressure blade were computed as steady-state flows and for two different turbine Reynolds number settings. Overall, the predictions compare very favorably with the measurement for both pressure and heat transfer at the mid-span location. A discussion of the features of the airfoil heat transfer distribution is included.

Developing a Combustor Simulator for Investigating High Pressure Turbine Aerodynamics and Heat Transfer

2004 ◽  
Author(s):  
M. D. Barringer ◽  
K. A. Thole ◽  
M. D. Polanka
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Test Facility ◽  
Temperature Profiles ◽  
High Pressure Turbine ◽  
Blow Down ◽  
Turbine Engine ◽  
The Impact

Within a gas turbine engine, the high pressure turbine vanes are subjected to very harsh conditions from the highly turbulent and hot gases exiting the combustor. The temperature and pressure fields exiting the combustor dictate the heat transfer and aero losses that occur in the turbine passages. To better understand these effects, the goal of this work is to develop an adjustable combustor exit profile simulator for the Turbine Research Facility (TRF) at the Air Force Research Laboratory (AFRL). The TRF is a high temperature, high pressure, short duration blow-down test facility that is capable of matching several aerodynamic and thermal non-dimensional engine parameters including Reynolds number, Mach number, pressure ratio, corrected mass flow, gas-to-metal temperature ratio, and corrected speed. The research objective was to design, install, and verify a non-reacting simulator device that provides representative combustor exit total pressure and temperature profiles to the inlet of the TRF turbine test section. This required the upstream section of the facility to be redesigned into multiple concentric annuli that serve the purpose of injecting high momentum dilution jets and low momentum film cooling jets into a central annular chamber, similar to a turbine engine combustor. The design of the simulator allows for variations in injection levels to generate turbulence and pressure profiles. It also can vary the dilution and film cooling temperatures to create a variety of temperature profiles consistent with real combustors. To date, the design and construction of the simulator device has been completed. All of the hardware has been trial fitted and the flow control shutter systems have been successfully installed and tested. Currently, verification testing is being performed to investigate the impact of the generated temperature, pressure, and turbulence profiles on turbine heat transfer and secondary flow development.

Heat Transfer Measurements and Predictions for a Modern, High-Pressure, Transonic Turbine, Including Endwalls

2006 ◽  
Author(s):  
James A. Tallman ◽  
Charles W. Haldeman ◽  
Michael G. Dunn ◽  
Anil K. Tolpadi ◽  
Robert F. Bergholz
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Turbulence Modeling ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Local Measurements ◽  
Transonic Turbine ◽  
The Ohio State University

This paper presents both measurements and predictions of the hot-gas-side heat transfer to a modern, one and 1/2 stage high-pressure, transonic turbine. Comparisons of the predicted and measured heat transfer are presented for each airfoil at three locations, as well as on the various endwalls and rotor tip. The measurements were performed using the Ohio State University Gas Turbine Laboratory Test Facility (TTF). The research program utilized an uncooled turbine stage at a range of operating conditions representative of the engine: in terms of corrected speed, flow function, stage pressure ratio, and gas-to-metal temperature ratio. All three airfoils were heavily instrumented for both pressure and heat transfer measurements at multiple locations. A 3-D, compressible, Reynolds-averaged Navier-Stokes CFD solver with k-ω turbulence modeling was used for the CFD predictions. The entire, 1-1/2 stage turbine was solved using a single computation, at two different Reynolds numbers. The CFD solutions were steady, with tangentially mass-averaged inlet/exit boundary condition profiles exchanged between adjacent airfoil-rows. Overall, the CFD heat transfer predictions compared very favorably with both the global operation of the turbine and with the local measurements of heat transfer. A discussion of the features of the turbine heat transfer distributions, and their association with the corresponding flow-physics, has been included.

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