Conjugate heat transfer in a gas turbine blade trailing-edge cavity

2002 ◽  
Author(s):  
S. Thakur ◽  
J. Wright
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Conjugate Heat Transfer ◽  
Gas Turbine Blade ◽  
Trailing Edge

Effect of Rotation on Heat Transfer in AR = 2:1 and AR = 4:1 Channels Connected by a Series of Crossover Jets

2021 ◽  
pp. 1-19
Author(s):  
Srivatsan Madhavan ◽  
Prashant Singh ◽  
Srinath V. Ekkad
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Flow Direction ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Cooling Flow ◽  
Liquid Crystal Thermography ◽  
Pin Fins ◽  
Rib Turbulators

Abstract Detailed heat transfer measurements using transient liquid crystal thermography were performed on a novel cooling design covering the mid-chord and trailing edge region of a typical gas turbine blade under rotation. The test section comprised of two channels with aspect ratio (AR) of 2:1 and 4:1, where the coolant was fed into the AR = 2:1 channel. Rib turbulators with a pitch-to-rib height ratio (p/e) of 10 and rib height-to-channel hydraulic diameter ratio (e/Dh) of 0.075 were placed in the AR = 2:1 channel at 60° relative to flow direction. The coolant after entering this section was routed to the AR = 4:1 section through a set of crossover jets. The 4:1 section had a realistic trapezoidal shape that mimics the trailing edge of an actual gas turbine blade. The pin fins were arranged in a staggered array with a center-to-center spacing of 2.5 times pin diameter. The trailing edge section consisted of radial and cutback exit holes for flow exit. Experiments were performed for Reynolds number of 20,000 at Rotation numbers (Ro) of 0, 0.1 and 0.14. The channel averaged heat transfer coefficient on trailing side was ~28% (AR = 2:1) and ~7.6% (AR = 4:1) higher than the leading side for Ro = 0.1. It is shown that the combination of crossover jets and pin-fins can be an effective method for cooling wedge shaped trailing edge channels over axial cooling flow designs.

A new conjugate heat transfer method to analyse a 3D steam cooled gas turbine blade with temperature-dependent material properties

2011 ◽  
Vol 226 (5) ◽  
pp. 1309-1320 ◽  
Author(s):  
M M Jafari ◽  
G Atefi ◽  
J Khalesi ◽  
A Soleymani
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Power Plants ◽  
Conjugate Heat Transfer ◽  
Three Dimensional ◽  
Computer Code ◽  
Gas Turbine Blade ◽  
Temperature Dependent ◽  
Transfer Method

The erosion of the hot regions in a gas turbine is one of the most important challenges encountered by the power plants. Though several numerical simulations of the problem have been reported so far, little is known to give accurate results. In this article, the thermoelastic behaviour of a gas turbine blade with internal steam-cooled channels positioned within a three-dimensional cascade configuration has been studied. A computer code based on the conjugate heat transfer method using the simultaneous solution of Navier–Stokes and heat transfer equations has been developed. From this study, the temperature distribution along with the stress values at high temperatures has been obtained. The blade parameters such as E, α, and K were considered to be a function of the temperature. In the previous works, usually only one or two of these parameters was considered as temperature dependent and the others constant. In this article, all the blade parameters, though making the equations highly non-linear, were considered as a function of temperature. The results have been compared with the available experimental data and a good agreement is observed. According to these findings, taking the temperature dependency of materials into account increases the estimations accuracy and brings the results closer to the reality.

Unsteady CFD Analysis of Turbulent Flow and Heat Transfer in a Gas Turbine Blade Trailing Edge Subjected to Rotation

2012 ◽  
Author(s):  
Domenico Borello ◽  
Giovanni Delibra ◽  
Cosimo Bianchini ◽  
Antonio Andreini
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Heated Surface ◽  
Heat Removal ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Flow And Heat Transfer ◽  
The Impact

Internal cooling of gas turbine blade represents a challenging task involving several different phenomena as, among others, highly three-dimensional unsteady fluid flow, efficient heat transfer and structural design. This paper focuses on the analysis of the turbulent flow and heat transfer inside a typical wedge–shaped trailing edge cooling duct of a gas turbine blade. In the configuration under scrutiny the coolant flows inside the duct in radial direction and it leaves the blade through the trailing edge after a 90 deg turning. At first an analysis of the flow and thermal fields in stationary conditions was carried out. Then the effects of rotational motion were investigated for a rotation number of 0.275. The rotation axis here considered is normal to the inflow and outflow bulk velocity, representing schematically a highly loaded blade configuration. The work aimed to i) analyse the dynamic of the vortical structures under the influence of strong body forces and the constraints induced by the internal geometry and ii) to study the impact of such motions on the mechanisms of heat removal. The final aim was to verify the design of the equipment and to detect the possible presence of regions subjected to high thermal loads. The analysis is carried out using the well assessed open source code OpenFOAM written in C++ and widely validated by several scientists and researchers around the world. The unsteadiness of the flow inside the trailing edge required to adopt models that accurately reconstructed the flow field. As the computational costs associated to LES (especially in the near wall regions) largely exceed the available resources, we chose for the simulation the SAS model of Menter, that was validated in a series of benchmark and industrially relevant test cases and allowed to reconstruct a part of the turbulence spectra through a scale-adaptive mechanism. Assessment of the obtained results with steady-state k-ω SST computations and available experimental results was carried out. The present analysis demonstrated that a strong unsteadiness develops inside the trailing edge and that the rotation generated strong secondary motions that enhanced the dynamic of heat removal, leading to a less severe temperature distribution on the heated surface w.r.t the non rotating case.

scholarly journals Performance prediction of trailing-edge cooling system of gas turbine blade using detached eddy simulation

2020 ◽  
Vol 1 (1) ◽  
pp. 16-21
Author(s):  
Agus Jamaldi ◽  
Hassan Khamis Hassan
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Cooling System ◽  
Computational Domain ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Blowing Ratio ◽  
Eddy Simulation ◽  
Pin Fins

This study aims to evaluate the performance of the trailing-edge (TE) cooling system in a gas turbine blade. Eddy Simulation (DES), based on the turbulence model of Spallart-Almaras (SA), was used to simulate the TE cooling system. A TE configuration with a five-row staggered pin-fin arrangement was employed as a computational domain. Three parameters, i.e., the coefficient of heat transfer on the pin-fins surface (hpin), the coefficient of discharge (CD), and the effectiveness of adiabatic film cooling were used to assess the performances. The findings denoted that the heat transfer fluctuations occurred on the surface of the pin-fins in each row. The discharge coefficient increased with the rising of the blowing ratio. The trend predicted data of effectiveness were in good agreement with realistic discrepancies compared to other researches, mainly for higher blowing ratio. The average effectiveness along the cut-off region was to be sensitive to the changes of the blowing ratio, which was attributed to the structures of turbulent flow along the mixing region.

Effect of Rotation on Heat Transfer in AR = 2:1 and AR = 4:1 Channels Connected by a Series of Crossover Jets

2021 ◽  
Author(s):  
Srivatsan Madhavan ◽  
Prashant Singh ◽  
Srinath V. Ekkad
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbine Blade ◽  
Trailing Edge ◽  
Cooling Flow ◽  
Liquid Crystal Thermography ◽  
Pin Fins ◽  
Rib Turbulators ◽  
Cooling Design

Abstract Detailed heat transfer measurements using transient liquid crystal thermography were performed on a novel cooling design covering the mid-chord and trailing edge region of a typical gas turbine blade under stationary and rotating conditions. The test section comprised of two channels with aspect ratio (AR) of 2:1 (mid-chord) and 4:1 (trailing edge), where the coolant was fed into the AR = 2:1 channel from the root. Rib turbulators with a pitch-to-rib height ratio (p/e) of 10 and rib height-to-channel hydraulic diameter ratio (e/Dh) of 0.075 were placed in the AR = 2:1 channel at an angle of 60° relative to the direction of flow. The coolant after entering this section was routed to the AR = 4:1 section through a set of crossover jets. The purpose of the crossover jets was to induce sideways impingement onto the pin fins that were placed in the 4:1 section to enhance heat transfer. The 4:1 section had a realistic trapezoidal shape that mimics the trailing edge of an actual gas turbine blade. The pin fins were arranged in a staggered array with a center-to-center spacing of 2.5 times the pin diameter in both spanwise and streamwise directions. The trailing edge section consisted of both radial and cutback exit holes for flow exit. Experiments were performed for a Reynolds number (ReDh(AR = 2:1)) of 20,000 at Rotation numbers (RoDh(AR = 2:1)) of 0, 0.1 and 0.14. The channel averaged heat transfer coefficient on trailing side was ∼28% (AR = 2:1) and ∼7.6% (AR = 4:1) higher than the leading side for Rotation number (Ro) of 0.1. It is shown that the combination of crossover jets and pin-fins can be an effective method for cooling wedge shaped trailing edge channels over axial cooling flow designs.

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.

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