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.

Effects of Boot-Shaped Rib On Heat Transfer Characteristics of Internal Cooling Turbine Blades

2020 ◽  
Author(s):  
Ky-Quang Pham ◽  
Quang-Hai Nguyen ◽  
Tai-Duy Vu ◽  
Cong-Truong Dinh
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Wall Friction ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Toe Angle

Abstract Gas turbine engine has been widely applied to many heavy industries, such as marine propulsion and aerospace fields. Increasing turbine inlet temperature is one of the major ways to improve the thermal efficiency of gas turbines. Internal cooling for gas turbine cooling system is one of the most commonly used approaches to reduce the temperature of blades by casting various kinds of ribs in serpentine passages to enhance the heat transfer between the coolant and hot surface of gas turbine blades. This paper presents an investigation of boot-shaped rib design to increase the heat transfer performances in the internal cooling turbine blades for gas turbine engines. By varying the design parameter configuration, the airflow is taken with higher momentum, and the minor vortex being at the front rib is relatively removed. The object of this investigation is increasing the reattachment airflow to wall and reducing the vortex occurring near the rib for improving the performances of heat transfer using three-dimensional Reynolds-averaged Navier-Stokes with the SST model. A parametric study of the boot-shaped rib design was performed using various geometric parameters related to the heel-angle, toe-angle, slope-height and rib-width to find their effect on the Nusselt number, temperature on the ribbed wall, friction factor ratio of the channel and thermal performance factor. The numerical results showed that the heat transfer performances are significantly increased with the heel-angle, toe-angle, slope-height, while that remained relatively constant with the rib-width.

scholarly journals Cooling and Sealing Air System in Industrial Gas Turbine Engines

1996 ◽  
Author(s):  
A. W. Reichert ◽  
M. Janssen
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Inlet Temperature ◽  
Turbine Inlet ◽  
Air System ◽  
Calculation System ◽  
Cooling Air

Siemens heavy duty Gas Turbines have been well known for their high power output combined with high efficiency and reliability for more than 3 decades. Offering state of the art technology at all times, the requirements concerning the cooling and sealing air system have increased with technological development over the years. In particular the increase of the turbine inlet temperature and reduced NOx requirements demand a highly efficient cooling and sealing air system. The new Vx4.3A family of Siemens gas turbines with ISO turbine inlet temperatures of 1190°C in the power range of 70 to 240 MW uses an effective film cooling technique for the turbine stages 1 and 2 to ensure the minimum cooling air requirement possible. In addition, the application of film cooling enables the cooling system to be simplified. For example, in the new gas turbine family no intercooler and no cooling air booster for the first turbine vane are needed. This paper deals with the internal air system of Siemens gas turbines which supplies cooling and sealing air. A general overview is given and some problems and their technical solutions are discussed. Furthermore a state of the art calculation system for the prediction of the thermodynamic states of the cooling and sealing air is introduced. The calculation system is based on the flow calculation package Flowmaster (Flowmaster International Ltd.), which has been modified for the requirements of the internal air system. The comparison of computational results with measurements give a good impression of the high accuracy of the calculation method used.

Recent Advances of Internal Cooling Techniques for Gas Turbine Airfoils

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Minking K. Chyu ◽  
Sin Chien Siw
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Demand ◽  
Major Elements ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Performance Goal ◽  
Turbine Inlet Temperature ◽  
Air Breathing ◽  
Turbine Inlet

The performance goal of modern gas turbine engines, both land-base and air-breathing engines, can be achieved by increasing the turbine inlet temperature (TIT). The level of TIT in the near future can reach as high as 1700 °C for utility turbines and over 1900 °C for advanced military engines. Advanced and innovative cooling techniques become one of the crucial major elements supporting the development of modern gas turbines, both land-based and air-breathing engines with continual increment of turbine inlet temperature (TIT) in order to meet higher energy demand and efficiency. This paper discusses state-of-the-art airfoil cooling techniques that are mainly applicable in the mainbody and trailing edge section of turbine airfoil. Potential internal cooling designs for near-term applications based on current manufacturing capabilities are identified. A literature survey focusing primarily on the past four to five years has also been performed.

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

2016 ◽  
Author(s):  
E. Burberi ◽  
D. Massini ◽  
L. Cocchi ◽  
L. Mazzei ◽  
A. Andreini ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Flow Field ◽  
Transfer Coefficient ◽  
Numerical Investigation ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Cooling System ◽  
Leading Edge ◽  
Internal Cooling

Increasing turbine inlet temperature is one of the main strategies used to accomplish the demands of increased performance of modern gas turbines. As a consequence, optimization of the cooling system is of paramount importance in gas turbine development. Leading edge represents a critical part of cooled nozzles and blades, given the presence of the hot gases stagnation point and the unfavourable geometry for cooling. This paper reports the results of a numerical investigation aimed at assessing the rotation effects on the heat transfer distribution in a realistic leading edge internal cooling system of a high pressure gas turbine blade. The numerical investigation was carried out in order to support and to allow an in-depth understanding of the results obtained in a parallel experimental campaign. The model is composed of a trapezoidal feeding channel which provides air to the cold bridge system by means of three large racetrack-shaped holes, generating coolant impingement on the internal concave leading edge surface, whereas four big fins assure the jets confinement. Air is then extracted through 4 rows of 6 holes reproducing the external cooling system composed of shower-head and film cooling holes. Experiments were performed in static and rotating conditions replicating the typical range of jet Reynolds number (Rej) from 10000 to 40000 and Rotation number (Roj) up to 0.05, for three crossflow cases representative of the working condition that can be found at blade tip, midspan and hub, respectively. Experimental results in terms of flow field measurements on several internal planes and heat transfer coefficient on the LE internal surface have been performed on two analogous experimental campaigns at University of Udine and University of Florence respectively. Hybrid RANS-LES models were used for the simulations, such as Scale Adaptive Simulation (SAS) and Detached Eddy Simulation (DES), given their ability to resolve the complex flow field associated with jet impingement. Numerical flow field results are reported in terms of both jet velocity profiles and 2D vector plots on symmetry and transversal internal planes, while the heat transfer coefficient distributions are presented as detailed 2D maps together with radial and tangential averaged Nusselt number profiles. A fairly good agreement with experimental measurements is observed, which represent a validation of the adopted computational model. As a consequence, the computed aerodynamic and thermal fields also allow an in-depth interpretation of the experimental results.

scholarly journals Development of Ceramic Stator Vane for 1500°C Class Gas Turbine

1996 ◽  
Author(s):  
Takashi Machida ◽  
Masato Nakayama ◽  
Katsuo Wada ◽  
Tooru Hisamatsu ◽  
Isao Yuri ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Loading ◽  
Cooling System ◽  
Internal Cooling ◽  
Ceramic Shell ◽  
Metal Core ◽  
Combustion Gas ◽  
Stator Vane

Employing ceramic materials for the critical components of industrial gas turbines is anticipated to improve the thermal efficiency of power plants. We have developed a first stage ceramic stator vane for a 1500°, 20MW class industrial gas turbine by improving our original one for a 1300°C class gas turbine. Our stator vane has a hybrid ceramic/metal structure composed of a ceramic shell, a metal core and a heat insulating layer. This composition increases the strength of the brittle ceramic parts and reduces the amount of cooling air. To improve the durability and reliability of the stator vane in 1500°C combustion gas, the ceramic shell uses silicon carbide instead of silicon nitride, and its configuration is improved. Furthermore, we use an internal cooling system to control the temperature of the metal core. Thermal loading cascade tests are conducted to prove the reliability and cooling performance of the stator vane.

New Insights From Conceptual Design of an Additive Manufactured 300 W Micro Gas Turbine Towards UAV Applications

2020 ◽  
Author(s):  
Lukas Badum ◽  
Boris Leizeronok ◽  
Beni Cukurel
Keyword(s):  
Heat Transfer ◽  
Energy Density ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Energy ◽  
High Energy Density ◽  
Heat Transfer Analysis ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Micro Gas Turbine

Abstract Owing to high energy density of hydrocarbon fuels, ultra-micro gas turbines with power outputs below 1 kW have potential as battery replacement in drones. To overcome the obstacles observed in previous works on gas turbines of this scale, novel gas turbine architecture is proposed based on conventional roller bearing technology that operates at up to 500,000 RPM and additively manufactured monolithic rotor in cantilevered configuration, equipped with internal cooling blades. The optimum turbomachinery design is elaborated using diabatic cycle calculation, coupled with turbomachinery meanline design. This approach provides new insights on interdependencies of heat transfer, component efficiency and system electric efficiency. Thereby, reduced design pressure ratio of 2.5 with 1200 K turbine inlet temperature is identified as most suitable for 300 W electric power output. In following, material properties and design constraints for the monolithic rotor are obtained from available additive manufacturing technologies. Rotordynamic simulations are then conducted for four available materials using simplified rotor model. CFD simulations are conducted to quantify compressor efficiency and conjugate heat transfer analysis is performed to assess the benefit of internal cooling cavity and vanes for different rotor materials. It is demonstrated that the cavity flow absorbs large heat flux from turbine to compressor, thus cooling the rotor structure and improving the diabatic cycle efficiency. Finally, results of this conceptual study show that ultra-micro gas turbine with electric efficiency of up to 5% is feasible, while energy density is increased by factor of 3.6, compared to lithium-ion batteries.

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.

Parametric Study of Inlet Cooling With Varied COP on Gas Turbine Performance

2014 ◽  
Author(s):  
Maryam Besharati-Givi ◽  
Xianchang Li
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
High Efficiency ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Turbine Performance ◽  
Compressor Inlet

Gas turbines play an important role in power generation, and it is therefore desired to operate gas turbines with high efficiency and power output. One of the most influential parameters on the performance of a gas turbine is the ambient condition. It is known that inlet cooling can improve the gas turbine performance, especially when the ambient temperature is high. This study examines the effect of inlet cooling with different operating parameters such as compressor inlet temperature, turbine inlet temperature, air fuel ratio, and pressure ratio. Furthermore, the coefficient of performance (COP) of the cooling system is considered a function of the ambient temperature. Aspen Plus software is used to simulate the system under a steady-flow condition. The results indicate that the cooling of the compressor inlet air can substantially improve the power output as well as the overall efficiency of system. More importantly, there exists an optimal temperature at which the inlet cooling should be operated to achieve the highest efficiency.

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.

New Insights From Conceptual Design of an Additive Manufactured 300 W Micro Gas Turbine Towards UAV Applications

2020 ◽  
Author(s):  
L. Badum ◽  
B. Leizeronok ◽  
B. Cukurel
Keyword(s):  
Heat Transfer ◽  
Energy Density ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Energy ◽  
High Energy Density ◽  
Heat Transfer Analysis ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Micro Gas Turbine

Abstract Owing to the high energy density of hydrocarbon fuels, ultra-micro gas turbines with power outputs below 1 kW have clear potential as battery replacement in drones. However, previous works on gas turbines of this scale revealed severe challenges due to air bearing failures, heat transfer from turbine to compressor, rotordynamic instability and manufacturing limitations. To overcome these obstacles, a novel gas turbine architecture is proposed based on conventional roller bearing technology that operates at up to 500,000 RPM and an additively manufactured monolithic rotor in cantilevered configuration, equipped with internal cooling blades. The optimum turbomachinery design is elaborated using diabatic cycle calculation, coupled with turbomachinery meanline design code. This approach provides new insights on the interdependencies of heat transfer, component efficiency and system electric efficiency. Thereby, a reduced design pressure ratio of 2.5 with 1200 K turbine inlet temperature is identified as most suitable for 300 W electric power output. In following, a review of available additive manufacturing technologies yields material properties, surface roughness and design constraints for the monolithic rotor. Rotordynamic simulations are then conducted for four available materials using a simplified rotor model to identify valid permanent magnet dimensions that would avoid operation close to bending modes. To complete the baseline engine architecture, a novel radial inflow combustor concept is proposed based on porous inert media combustion. CFD simulations are conducted to quantify compressor efficiency and conjugate heat transfer analysis of the monolithic rotor is performed to assess the benefit of the internal cooling cavity and vanes for different rotor materials. It is demonstrated that the cavity flow absorbs large amount of heat flux from turbine to compressor, thus cooling the rotor structure and improving the diabatic cycle efficiency. Finally, the results of this conceptual study show that ultra-micro gas turbine with electric efficiency of up to 5% is feasible, while energy density is increased by factor of 3.6, compared to lithium-ion batteries.

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