Fundamental Gas Turbine Heat Transfer

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Industrial Applications ◽  
Future Research ◽  
Gas Turbine Heat Transfer ◽  
Cooling Air

Gas turbines are used for aircraft propulsion and land-based power generation or industrial applications. Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperatures (RIT). Current advanced gas turbine engines operate at turbine RIT (1700 °C) far higher than the melting point of the blade material (1000 °C); therefore, turbine blades are cooled by compressor discharge air (700 °C). To design an efficient cooling system, it is a great need to increase the understanding of gas turbine heat transfer behaviors within complex 3D high-turbulence unsteady engine-flow environments. Moreover, recent research focuses on aircraft gas turbines operating at even higher RIT with limited cooling air and land-based gas turbines burn coal-gasified fuels with a higher heat load. It is important to understand and solve gas turbine heat transfer problems under new harsh working environments. The advanced cooling technology and durable thermal barrier coatings play critical roles for the development of advanced gas turbines with near zero emissions for safe and long-life operation. This paper reviews fundamental gas turbine heat transfer research topics and documents important relevant papers for future research.

Advanced Cooling in Gas Turbines 2016 Max Jakob Memorial Award Paper

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Cooling System ◽  
Turbine Rotor ◽  
Research Trend ◽  
Future Research ◽  
Gas Turbine Heat Transfer

Gas turbines have been extensively used for aircraft engine propulsion, land-based power generation, and industrial applications. Power output and thermal efficiency of gas turbines increase with increasing turbine rotor inlet temperatures (RIT). Currently, advanced gas turbines operate at turbine RIT around 1700 °C far higher than the yielding point of the blade material temperature about 1200 °C. Therefore, turbine rotor blades need to be cooled by 3–5% of high-pressure compressor air around 700 °C. To design an efficient turbine blade cooling system, it is critical to have a thorough understanding of gas turbine heat transfer characteristics within complex three-dimensional (3D) unsteady high-turbulence flow conditions. Moreover, recent research trend focuses on aircraft gas turbines that operate at even higher RIT up to 2000 °C with a limited amount of cooling air, and land-based power generation gas turbines (including 300–400 MW combined cycles with 60% efficiency) burn alternative syngas fuels with higher heat load to turbine components. It is important to understand gas turbine heat transfer problems with efficient cooling strategies under new harsh working environments. Advanced cooling technology and durable thermal barrier coatings (TBCs) play most critical roles for development of new-generation high-efficiency gas turbines with near-zero emissions for safe and long-life operation. This paper reviews basic gas turbine heat transfer issues with advanced cooling technologies and documents important relevant papers for future research references.

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.

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.

Pulsed Impingement Turbine Cooling and its Effect on the Efficiency of Gas Turbines With Pressure Gain Combustion

2020 ◽  
Author(s):  
Nicolai Neumann ◽  
Dieter Peitsch ◽  
Arne Berthold ◽  
Frank Haucke ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Impingement Cooling ◽  
Turbine Cooling ◽  
Pressure Gain Combustion ◽  
Cooling Air ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Abstract Performance improvements of conventional gas turbines are becoming increasingly difficult and costly to achieve. Pressure Gain Combustion (PGC) has emerged as a promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine cycle. Previous cycle analyses considering turbine cooling methods have shown that the application of pressure gain combustion may require more turbine cooling air. This has a direct impact on the cycle efficiency and reduces the possible efficiency gain that can potentially be harvested from the new combustion technology. Novel cooling techniques could unlock an existing potential for a further increase in efficiency. Such a novel turbine cooling approach is the application of pulsed impingement jets inside the turbine blades. In the first part of this paper, results of pulsed impingement cooling experiments on a curved plate are presented. The potential of this novel cooling approach to increase the convective heat transfer in the inner side of turbine blades is quantified. The second part of this paper presents a gas turbine cycle analysis where the improved cooling approach is incorporated in the cooling air calculation. The effect of pulsed impingement cooling on the overall cycle efficiency is shown for both Joule and PGC cycles. In contrast to the authors’ anticipation, the results suggest that for relevant thermodynamic cycles pulsed impingement cooling increases the thermal efficiency of Joule cycles more significantly than it does in the case of PGC cycles. Thermal efficiency improvements of 1.0 p.p. for pure convective cooling and 0.5 p.p. for combined convective and film with TBC are observed for Joule cycles. But just up to 0.5 p.p. for pure convective cooling and 0.3 p.p. for combined convective and film cooling with TBC are recorded for PGC cycles.

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.

Experimental and Numerical Analysis of Gas Turbine Blades With Different Internal Cooling Geometries

2009 ◽  
Author(s):  
M. Eifel ◽  
V. Caspary ◽  
H. Ho¨nen ◽  
P. Jeschke
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Base Flow ◽  
Internal Cooling ◽  
Turbine Rotor Blade ◽  
Flow Phenomena ◽  
Sst Turbulence Model

This paper presents the effects of major geometrical modifications to the interior of a convection cooled gas turbine rotor blade. The analysis of the flow is performed experimentally with flow visualization via paint injection into water whereas the flow and the heat transfer are investigated numerically with Ansys CFX utilizing the SST turbulence model. Two sets of calculations are carried out, one under the same conditions as the experiments and another according to realistic hot gas conditions with conjugate heat transfer. The aim is to identify flow phenomena altering the heat transfer in the blade and to manipulate them in order to reduce the thermal load of the material. The operating point of the geometric base configuration is set to Re = 50,000 at the inlet while for the modified geometries the pressure ratio is held constant compared to the base. Flow structures and heat transfer conditions are evaluated and are linked to specific geometric features. Among several investigated configurations one could be identified that leads to a cooling effectiveness 15% larger compared to the base.

Gas Turbine Combustor Cooling by Augmented Backside Convection

1979 ◽  
Vol 101 (1) ◽  
pp. 109-115 ◽  
Author(s):  
D. M. Evans ◽  
M. L. Noble
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Film Cooling ◽  
Cooling System ◽  
Exhaust Gas ◽  
Confined Space ◽  
Gas Turbine Combustor ◽  
Exhaust Gas Emission ◽  
Cooling Air ◽  
Cooling Methods

Traditionally, gas turbine combustor walls have been cooled by one or more of the various film cooling methods. The current motivation to control exhaust gas emission composition has led to the serious consideration of backside convection wall cooling, where the cooling air is introduced to the main gas stream not prior to the dilution zone. Due to the confined space and the severe nature of the wall cooling problem, it is essential to maximize the heat transfer/pumping power characteristic, which suggests an augmented convection technique. A particular heat transfer design of a combustor cooled by means of transverse rib turbulence promoters applied to the exterior wall of the annular spaces surrounding the primary and secondary zones is described. Analytical methods for designing such a cooling system are reviewed and a comparison between analytical and experimental results is presented.

Experimental and Numerical Analysis of Gas Turbine Blades With Different Internal Cooling Geometries

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
M. Eifel ◽  
V. Caspary ◽  
H. Hönen ◽  
P. Jeschke
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Base Flow ◽  
Internal Cooling ◽  
Turbine Rotor Blade ◽  
Flow Phenomena ◽  
Sst Turbulence Model

This paper presents the effects of major geometrical modifications to the interior of a convection cooled gas turbine rotor blade. The analysis of the flow is performed experimentally with flow visualization via paint injection into water, whereas the flow and the heat transfer are investigated numerically with ANSYS CFX, utilizing the SST turbulence model. Two sets of calculations are carried out: one under the same conditions as the experiments and another according to realistic hot gas conditions with conjugate heat transfer. The aim is to identify flow phenomena altering the heat transfer in the blade and to manipulate them in order to reduce the thermal load of the material. The operating point of the geometric base configuration is set to Re=50,000 at the inlet while for the modified geometries, the pressure ratio is held constant compared with the base. Flow structures and heat transfer conditions are evaluated and are linked to specific geometric features. Among several investigated configurations one could be identified that leads to a cooling effectiveness 15% larger compared with the base.

Experimental and Numerical Analysis of the Flow Structure and Dust Separation Inside a Pre-Swirl Cooling Air System

2003 ◽  
Author(s):  
O. Schneider ◽  
H. J. Dohmen ◽  
F.-K. Benra ◽  
D. Brillert
Keyword(s):  
Numerical Analysis ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Flow Conditions ◽  
Test Rig ◽  
Complex Flow ◽  
Air System ◽  
Cooling Air

Improvements in efficiency and performance of gas turbines require a better understanding of the internal cooling air system which provides the turbine blades with cooling air. With the increase of cooling air passing through the internal air system, a greater amount of air borne particles is transported to the film cooling holes at the turbine blade surface. In spite of their small size, these holes are critical for blockage. Blockage of only a few holes could have harmful effects on the cooling film surrounding the blade. As a result, a reduced mean time between maintenance or even unexpected operation faults of the gas turbine during operation could occur. Experience showed a complex interaction of cooling air under different flow conditions and its particle load. To get more familiar with all these influences and the system itself, a test rig has been built. With this test rig, the behavior of particles in the internal cooling air system can be studied at realistic flow conditions compared to a modern, heavy duty gas turbine. It is possible to simulate different particle sizes and dust concentrations in the coolant air. The test rig has been designed to give information about the quantity of separated particles at various critical areas of the internal air system [1]. The operation of the test rig as well as analysis of particles in such a complex flow system bear many problems, addressed in previous papers [1,2,3]. New theoretical studies give new and more accurate results, compared to the measurements. Furthermore the inspection of the test rig showed dust deposits at unexpected positions of the flow path, which will be discussed by numerical analysis.

scholarly journals Heat Transfer Phenomena in Gas Turbines

1980 ◽  
Author(s):  
J. R. Taylor
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Gas Turbine Engine ◽  
Transfer Coefficients ◽  
Turbine Engine ◽  
Film Cooling Effectiveness ◽  
Heat Transfer Coefficients

A discussion of the problems encountered in prediction of heat transfer in the turbine section of a gas turbine engine is presented. Areas of current gas turbine engine is presented. Areas of current concern to designers where knowledge is deficient or lacking are elucidated. Consideration is given to methods and problems associated with determination of heat transfer coefficients, external gas temperatures, and, where applicable, film cooling effectiveness. The paper is divided into parts dealing with turbine airfoil heat transfer, endwall heat transfer, and heat transfer in the internal cavities of cooled turbine blades. Recent literature dealing with these topics is listed.

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