Evaluation of Numerical Methods to Predict Temperature Distributions of an Experimentally Investigated Convection-Cooled Gas-Turbine Blade

2017 ◽  
Author(s):  
E. Findeisen ◽  
B. Woerz ◽  
M. Wieler ◽  
P. Jeschke ◽  
M. Rabs
Keyword(s):  
Heat Transfer ◽  
Numerical Methods ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Cooling System ◽  
Fe Model ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Temperature Distributions

This paper presents two different numerical methods to predict the thermal load of a convection-cooled gas-turbine blade under realistic operating temperature conditions. The subject of the investigation is a gas-turbine rotor blade equipped with an academic convection-cooling system and investigated at a cascade test-rig. It consists of three cooling channels, which are connected outside the blade, so allowing cooling air temperature measurements. Both methods use FE models to obtain the temperature distribution of the solid blade. The difference between these methods lies in the generation of the heat transfer coefficients along the cooling channel walls which serve as a boundary condition for the FE model. One method, referred to as the FEM1D method, uses empirical one-dimensional correlations known from the available literature. The other method, the FEM2D method, uses three-dimensional CFD simulations to obtain two-dimensional heat transfer coefficient distributions. The numerical results are compared to each other as well as to experimental data, so that the benefits and limitations of each method can be shown and validated. Overall, this paper provides an evaluation of the different methods which are used to predict temperature distributions in convection-cooled gas-turbines with regard to accuracy, numerical cost and the limitations of each method. The temperature profiles obtained in all methods generally show good agreement with the experiments. However, the more detailed methods produce more accurate results by causing higher numerical costs.

Evaluation of FEM Based Methods to Predict Temperature Distributions of a Convection Cooled Gas Turbine Blade

2014 ◽  
Author(s):  
B. Woerz ◽  
Y. Mick ◽  
E. Findeisen ◽  
P. Jeschke ◽  
M. Rabs
Keyword(s):  
Heat Transfer ◽  
Numerical Methods ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Cooling System ◽  
Three Dimensional ◽  
Gas Turbine Blade ◽  
Cooling Channels ◽  
Hot Gas

This paper presents different numerical methods to predict the thermal load of a convection cooled gas turbine blade under realistic operating temperature conditions. The subject of the investigation is a gas turbine rotor blade which is equipped with a state-of-the-art convection cooling system. Firstly, two FEM based methods are introduced. One method, referred to as FEM1D method, uses empirical correlations from the open literature to obtain one dimensional heat transfer coefficients along one flow line inside the cooling channels while in the hot gas path a three dimensional CFD simulation is used. The second method (FEM2D) uses three dimensional CFD simulations to obtain two dimensional heat transfer coefficient distributions for both, the inner cooling channels and the hot gas path. The results from both numerical methods are compared with each other and are validated with experimental data, quantifying also their accuracy limits. In total this paper gives an evaluation of two different FEM methods to predict temperature distribution in convection cooled gas turbines. Their accuracy, numerical cost and limitations are evaluated. It turns out that the temperature profiles gained by both methods are generally in good agreement with the experiments. However, while causing higher numerical costs the more detailed FEM2D method achieves more accurate results.

Short-Duration Measurements and Numerical Simulation of Heat Transfer Along the Suction Side of a Film-Cooled Gas Turbine Blade

1985 ◽  
Vol 107 (4) ◽  
pp. 991-997 ◽  
Author(s):  
C. Camci ◽  
T. Arts
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Suction Side ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Isentropic Compression ◽  
Curvature Effects ◽  
Convex Wall

This paper deals with an experimental investigation of heat transfer across the suction side of a high-pressure, film-cooled gas turbine blade and with an attempt to numerically predict this quantity both with and without film cooling. The measurements were performed in the VKI isentropic compression tube facility under well-simulated gas turbine conditions. Data measured in a stationary frame, with and without film cooling, are presented. The predictions of convective heat transfer, including streamwise curvature effects, are compared with the measurements. A new approach to determine the augmented mixing lengths near the ejection holes on a highly convex wall is discussed and numerical results agree well with experimentally determined heat transfer coefficients in the presence of film cooling.

Rotating Effects on Heat Transfer Rate in a Cooling Air Passage of a Gas Turbine Blade

2004 ◽  
Author(s):  
Fernando Z. Sierra ◽  
Juan C. Garci´a ◽  
Janusz Kubiak ◽  
Gustavo Urquiza
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Heat Transfer Rate ◽  
Turbine Blade ◽  
Rotation Rate ◽  
Gas Turbines ◽  
Transfer Rate ◽  
Gas Turbine Blade ◽  
Air Passage ◽  
Cooling Air

In this paper numerical results on the effects of rotation on heat transfer rates in a cooling air passage that belongs to a gas turbine blade are presented. A 180° turn about has been considered into the computations. Rotation rates of 1145, 2800 and 3600 rpm were considered into the analysis. Comparisons for a Re = 53 000 with literature published results showed a good agreement. The simulation has been based on the finite volume approach of a 3-D flow using a second moment closure model for modeling the turbulence in the air passage. The results indicate that the rotation rate produces important changes in the heat transfer rate. In this work heat transfer has been characterized through the Nusselt number, along the air flowing path. A rotation rate of 3600 rpm produces an increment of the heat transfer rate by 14% along the inlet edge of the blade compared with the condition of no rotation. However, a decrease of 16.7% is observed in the outlet edge under the same conditions, compared against the non rotating condition. The situation is drastic in the tip region of the blade where more than 18.5% higher heating rate is observed for the same rotating speed. These results correspond to the outer internal wall of the blade passage, while the situation for the inner wall are in general less severe. The velocity field shows the formation of several secondary cells of flow which may represent stagnation regions for both pressure and heat transfer. These secondary cells are observed mainly in the region of the turn of 180°. The dynamics of these cells are important for the performance and design of the cooling system in gas turbines.

scholarly journals Detailed Film Cooling Measurements over a Gas Turbine Blade Using a Transient Liquid Crystal Image Technique

2001 ◽  
Vol 7 (6) ◽  
pp. 415-424 ◽  
Author(s):  
Hui Du ◽  
Srinath V. Ekkad ◽  
Je-Chin Han ◽  
C. Pang Lee
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Blowing Ratio ◽  
Image Technique

Detailed heat transfer coefficient and film effectiveness distributions over a gas turbine blade with film cooling are obtained using a transient liquid crystal image technique. The test blade has three rows of film holes on the leading edge and two rows each on the pressure and suction surfaces. A transient liquid crystal technique maps the entire blade midspan region, and helps provide detailed measurements, particularly near the film hole. Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity is5.3×105. Two different coolants (air andCo2) were used to simulate coolant density effect. Coolant blowing ratio was varied between 0.8 and 1.2 for air injection and 0.4–1.2 forCo2injection. Results show that film injection promotes earlier laminar-turbulent boundary layer transition on the suction surface and also enhances local heat transfer coefficients (up to 80%) downstream of injection. An increase in coolant blowing ratio produces higher heat transfer coefficients for both coolants. This effect is stronger immediately downstream of injection holes. Film effectiveness is highest at a blowing ratio of 0.8 for air injection and at a blowing ratio of 1.2 forCo2injection. Such detailed results will help provide insight into the film cooling phenomena on a gas turbine blade.

Study on Relevant Effects Concerning Heat Transfer of a Convection Cooled Gas Turbine Blade Under Realistic Engine Temperature Conditions

2013 ◽  
Author(s):  
Y. Mick ◽  
B. Wörz ◽  
E. Findeisen ◽  
P. Jeschke ◽  
V. Caspary
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Cooling System ◽  
Gas Turbine Blade ◽  
Temperature Conditions ◽  
The Impact ◽  
Operating Points

This paper presents a study of the temperature distribution of a convection cooled gas turbine blade under realistic operating temperature conditions using experimental and numerical methods. The analysis is performed experimentally in a linear cascade with exhaust gas from a kerosene combustor. Detailed information at different operating points is taken from the experiments for which conjugate heat transfer (CHT) simulations with ANSYS CFX are carried out. By comparing the experimental and numerical results, the required complexity of the simulations is defined. The subject of this study is a gas turbine rotor blade equipped with a state-of-the-art internal convection cooling system. The test rig enables the examination of the blade at temperatures up to 1300K. The temperature distribution of the blade is measured using thermocouples. The calculations are carried out using the SST turbulence model, the Gamma Theta transition model and the discrete transfer radiation model. The influence of hot gas properties and radiation effects are analysed at three different operating points. This paper gives a quantitative overview of the impact of the mentioned parameters on temperature level and distribution as well as thermal stresses in a convection cooled blade under realistic engine temperature conditions.

A Predictive Model for Preliminary Gas Turbine Blade Cooling Analysis

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Nafiz H. K. Chowdhury ◽  
Hootan Zirakzadeh ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Predictive Model ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Internal Boundary ◽  
Gas Turbine Blade ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Temperature Distributions

The growing trend to achieve a higher turbine inlet temperature (TIT) in the modern gas turbine industry requires a more efficient and advanced cooling system design. Therefore, a complete study of heat transfer is necessary to predict the thermal loadings on the gas turbine vanes and blades. In the current work, a predictive model for the gas turbine blade cooling analysis has been developed. The model is capable of calculating the distribution of coolant mass flow rate (MFR) and metal temperatures of a turbine blade using the mass and energy balance equations at given external and internal boundary conditions. Initially, the performance of the model is validated by demonstrating its capability to predict the temperature distributions for a NASA E3 blade. The model is capable of predicting the temperature distributions with reasonable accuracy, especially on the suction side (SS). Later, this paper documents the overall analysis for the same blade profile but at different boundary conditions to demonstrate the flexibility of the model for other cases. Additionally, guidelines are provided to obtain external heat transfer coefficient (HTC) distributions for the highly turbulent mainstream.

Heat Transfer Coefficient on the Squealer Tip and Near Squealer Tip Regions of a Gas Turbine Blade

2002 ◽  
Author(s):  
Jae Su Kwak ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Rotor Blade ◽  
Intensity Level ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Detailed heat transfer coefficient distributions on a squealer tip of a gas turbine blade were measured using a hue detection based transient liquid crystals technique. The heat transfer coefficients on the shroud and near tip region of the pressure and suction sides of a blade were also measured. Tests were performed on a five-bladed linear cascade with blow down facility. The blade was a 2-dimensional model of a first stage gas turbine rotor blade with a profile of a GE-E3 aircraft gas turbine engine rotor blade. The Reynolds number based on the cascade exit velocity and axial chord length of a blade was 1.1×106 and the total turning angle of the blade was 97.7°. The overall pressure ratio was 1.23 and the inlet and exit Mach number were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7%. The heat transfer measurements were taken at the three different tip gap clearances of 1.0%, 1.5% and 2.5% of blade span. Results showed that the overall heat transfer coefficient on the squealer tip was higher than that on the shroud and the near tip region of the pressure and suction side. Results also showed that the heat transfer coefficients on the squealer tip and its shroud were lower than that on the plane tip and shroud, but the heat transfer coefficients on the near tip region of suction and pressure sides were higher for the squealer tip case.

Heat Transfer Coefficients on the Squealer Tip and Near Squealer Tip Regions of a Gas Turbine Blade

2003 ◽  
Vol 125 (4) ◽  
pp. 669-677 ◽  
Author(s):  
Jae Su Kwak ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Rotor Blade ◽  
Pressure Ratio ◽  
Intensity Level ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Blow Down ◽  
Heat Transfer Coefficients

Detailed heat transfer coefficient distributions on a squealer tip of a gas turbine blade were measured using a hue detection based transient liquid crystals technique. The heat transfer coefficients on the shroud and near tip regions of the pressure and suction sides of a blade were also measured. Tests were performed on a five-bladed linear cascade with a blow-down facility. The blade was a two-dimensional model of a first stage gas turbine rotor blade with a profile of a GE-E3 aircraft gas turbine engine rotor blade. The Reynolds number based on the cascade exit velocity and axial chord length of a blade was 1.1×106 and the total turning angle of the blade was 97.7 deg. The overall pressure ratio was 1.2 and the inlet and exit Mach number were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7 percent. The heat transfer measurements were taken at the three different tip gap clearances of 1.0 percent, 1.5 percent, and 2.5 percent of blade span. Results showed that the overall heat transfer coefficients on the squealer tip were higher than that on the shroud surface and the near tip regions of the pressure and suction sides. Results also showed that the heat transfer coefficients on the squealer tip and its shroud were lower than that on the plane tip and shroud. However, the reductions of heat transfer coefficients near the tip regions of the pressure and suction sides were not remarkable.

Effects of Tip Geometry and Tip Clearance on the Mass/Heat Transfer From a Large-Scale Gas Turbine Blade

2002 ◽  
Author(s):  
M. Papa ◽  
R. J. Goldstein ◽  
F. Gori
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Flow Visualization ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Tip Clearance ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Average Mass ◽  
Naphthalene Sublimation Technique

An experimental investigation has been performed to measure average and local mass transfer coefficients on the tip of a gas turbine blade using the naphthalene sublimation technique. The heat/mass transfer analogy can be applied to obtain heat transfer coefficients from the measured mass transfer data. Flow visualization on the tip surface is provided using an oil dot technique. Two different tip geometries are considered: a squealer tip and a winglet-squealer tip having a winglet on the pressure side and a squealer on the suction side of the blade. Measurements have been taken at tip clearance levels ranging from 0.6% to 3.6% of actual chord. The exit Reynolds number based on actual chord is approximately 7.2 × 105 for all measurements. Flow visualization shows impingement and recirculation regions on the blade tip surface, providing an interpretation of the mass transfer distributions and offering insight into the fluid dynamics within the gap. For both tip geometries the tip clearance level has a significant effect on the mass transfer distribution. The squealer tip has a higher average mass transfer that sensibly decreases with gap level, whereas a more limited variation with gap level is observed for the average mass transfer from the winglet-squealer tip.

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