Review of Gas Turbine Internal Cooling Improvement Technology

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Farah Nazifa Nourin ◽  
Ryoichi S. Amano
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Cooling System ◽  
Guide Vane ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Pin Fins ◽  
Rib Turbulators

Abstract The higher firing temperature reflects the higher efficiency of the gas turbine. However, using higher temperatures is limited as it may cause a rupture, bending, or failure of the turbine blades. Hence, the development of an effective internal cooling system of the gas turbine blade is essential. At the same time, it is necessary to ensure the lowest possible penalty on the thermodynamics performance cycle. Researchers are working over the years to find out the efficient cooling channel design with high transfer while the lowest pressure drop. They ran several cases both numerically and experimentally. This paper reviews the published research in the various methods of gas turbine internal cooling, such as using rib turbulators, dimples, jet impingement, pin fins, and guide vane, of the gas turbine blade.

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.

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.

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.

Novel Technology for Gas Turbine Blade Effusion Cooling

2006 ◽  
Author(s):  
Lorenzo Battisti ◽  
Roberto Fedrizzi ◽  
Giovanni Cerri
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Innovative Technology ◽  
Gas Turbine Blade ◽  
Combustion Chambers ◽  
Reliable Technique

Gas turbine combustion chambers and turbine blades require better cooling techniques to cope with the increase in operating temperatures with each new engine model. Current gas turbine inlet temperatures are approaching 2000 K. Such extreme temperatures, combined with a highly dynamic environment, result in major stress on components, especially combustion chamber and blades of the first turbine stages. A technique that has been extensively investigated is transpiration cooling, for both combustion chambers and turbine blades. Transpiration-cooled components have proved an effective way to achieve high temperatures and erosion resistance for gas turbines operating in aggressive environments, though there is a shortage of durable and proven technical solutions. Effusion cooling (full-coverage discrete hole film cooling), on the other hand, is a relatively simpler and more reliable technique offering a continuous coverage of cooling air over the component’s hot surfaces. This paper presents an innovative technology for the efficient effusion cooling of the combustor wall and turbine blades. The dedicated electroforming process used to manufacture effusive film cooling systems, called Poroform®, is illustrated. A numerical model is also presented, developed specifically for designing the distributions of the diameter and density of the holes on the cooled surface with a view to reducing the metal’s working temperature and achieving isothermal conditions for large blade areas. Numerical simulations were used to design the effusive cooling system for a first-stage gas turbine blade. The diameter, density and spacing of the holes, and the adiabatic film efficiency are discussed extensively to highlight the cooling capacity of the effusive system.

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.

Influence of converging conical hole angles on jet impingement blade cooling of gas turbine blade leading edge

2022 ◽  
Author(s):  
S. Sathish ◽  
S. Seralathan ◽  
Mohan Sai Narayan Ch ◽  
V. Mohammed Rizwan ◽  
U. Prudhvi Varma ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Gas Turbine Blade ◽  
Blade Cooling ◽  
Blade Leading Edge

Comparison of Showerhead Jet Impingement Configurations on Leading Edge of a Gas Turbine Blade

2019 ◽  
Author(s):  
Alankrita Singh ◽  
B. V. S. S. S. Prasad
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Test Section ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Jet Impingement ◽  
Turbulent Intensity ◽  
Gas Turbine Blade ◽  
Mean Velocity ◽  
Jet Interactions

Abstract Anemometry measurements are made on three novel, equilaterally staggered showerhead cooling configurations of jet impingement, for the leading edge of a gas turbine blade. In all the configurations, there are five jet impingement tubes in the form of a showerhead, wherein the central jet is circular and the remaining four neighboring jets have either circular or ±45° chamfer at one of its end. Flow characteristics of these jet configurations are analyzed by determining the mean velocity and the turbulent intensity of jets. The differences in the flow characteristics of these arrangements occur due to the changes in jet velocity profile and jet-to-jet interactions. The turbulent intensity is primarily responsible for augmentation in heat transfer of the test section. The uniform cooling of test section is represented by an “uniformity index” a high value of which is desirable for material durability. The Nusselt number is correlated with Reynolds number and turbulent intensity for all the three configurations.

Effect of Rotation on a Gas Turbine Blade Internal Cooling System: Numerical Investigation

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
E. Burberi ◽  
D. Massini ◽  
L. Cocchi ◽  
L. Mazzei ◽  
A. Andreini ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Internal Heat ◽  
Jet Impingement ◽  
Experimental Results ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Eddy Simulation

Increasing turbine inlet temperature is one of the main strategies used to accomplish the demand for increased performance of modern gas turbines. Thus, optimization of the cooling system is becoming of paramount importance in gas turbine development. Leading edge (LE) represents a critical part of cooled nozzles and blades, given the presence of the hot gases stagnation point, and the unfavorable geometrical characteristics for cooling purposes. This paper reports the results of a numerical investigation, carried out to support a parallel experimental campaign, aimed at assessing the rotation effects on the internal heat transfer coefficient (HTC) distribution in a realistic LE cooling system of a high pressure blade. Experiments were performed in static and rotating conditions replicating a typical range of jet Reynolds number (10,000–40,000) and Rotation number (0–0.05). The experimental results consist of flowfield measurements on several internal planes and HTC distributions on the LE internal surface. Hybrid RANS–large eddy simulation (LES) models were exploited for the simulations, such as scale adaptive simulation and detached eddy simulation, given their ability to resolve the complex flowfield associated with jet impingement. Numerical flowfield results are reported in terms of both jet velocity profiles and 2D vector plots on two internal planes, while the HTC distributions are presented as detailed 2D maps together with averaged Nusselt number profiles. A fairly good agreement with experiments is observed, which represents a validation of the adopted modeling strategy, allowing an in-depth interpretation of the experimental results.

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