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.

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.

Novel Gas Turbine Blade Leading Edge Cooling Configuration Using Advanced Double Swirl Chambers

2015 ◽  
Author(s):  
Karsten Kusterer ◽  
Gang Lin ◽  
Takao Sugimoto ◽  
Dieter Bohn ◽  
Ryozo Tanaka ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Leading Edge ◽  
Gas Turbine Blade ◽  
Stagnation Line ◽  
Impingement Cooling ◽  
Cooling Technology ◽  
Cooling Air ◽  
Blade Leading Edge

The Double Swirl Chambers (DSC) cooling technology, which has been introduced and developed by the authors, has the potential to be a promising cooling technology for further increase of gas turbine inlet temperature and thus improvement of the thermal efficiency. The DSC cooling technology establishes a significant enhancement of the local internal heat transfer due to the generation of two anti-rotating swirls. The reattachment of the swirl flows with the maximum velocity at the center of the chamber leads to a linear impingement effect on the internal surface of the blade leading edge nearby the stagnation line of gas turbine blade. Due to the existence of two swirls both the suction side and the pressure side of the blade near the leading edge can be very well cooled. In this work, several advanced DSC cooling configurations with a row of cooling air inlet holes have been investigated. Compared with the standard DSC cooling configuration the advanced ones have more suitable cross section profiles, which enables better accordance with the real blade leading edge profile. At the same time these configurations are also easier to be manufactured in a real blade. These new cooling configurations have been numerically compared with the state of the art leading edge impingement cooling configuration. With the same configuration of cooling air supply and boundary conditions the advanced DSC cooling presents 22–26% improvement of overall heat transfer and 3–4% lower total pressure drop. Along the stagnation line the new cooling configuration can generate twice the heat flux than the standard impingement cooling channel. The influence of spent flow in the impinging position and impingement heat transfer value is in the new cooling configurations much smaller, which leads to a much more uniform heat transfer distribution along the chamber axial direction.

Experimental Analysis of the Heat Transfer Variations Within an Internal Passage of a Typical Gas Turbine Blade Using Varied Internal Geometries

2012 ◽  
Author(s):  
Todd Hahn ◽  
Bryant Deakins ◽  
Andrew Buechler ◽  
Sourabh Kumar ◽  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Gas Turbine ◽  
Heat Transfer Rate ◽  
Turbine Blade ◽  
Experimental Analysis ◽  
Transfer Rate ◽  
Copper Foil ◽  
Nusselt Numbers ◽  
Turbulent Air Flow

This paper describes the experimental analysis of the heat transfer rate within an internal passage of a typical gas turbine blade using varied internal geometries. This method of alteration, using rib turbulator’s within the serpentine cooling passages of a hollow turbine blade, has proven to drastically cool turbine blades more significantly than a smooth channel alone. Our emphasis is to determine which rib geometry will yield the highest heat transfer rate, which was examined in the form of a comparison between theoretical to experimental Nusselt numbers. For testing purposes, an enclosed 2 in. × 2 in. square Plexiglas channel was constructed to model an internal cooling passage within a turbine blade. Silicon heat strips, wrapped in copper foil, were placed on the bottom surface of the channel to ensure even heat distribution throughout. To measure internal surface temperatures, thermocouples were placed on the surface of heat plate as well as in the opening of the channel throughout. The four different rib geometries which were individually wrapped in copper foil were then placed on top of the heating element. To compare the rib geometry results with a control, a test was run with no ribs. To simulate turbulent air flow through the channel, a blower supplied velocities of 23.88 m/s and 27.86 m/s. These velocities yielded a Reynolds number ranging between 70,000 and 90,000. Final results were found in the form of the experimental Nusselt number divided by the theoretical Nusselt number, a standard when comparing surface heat transfer rates. The 60 degree staggered arrow geometry pointing away from the inlet and outlet (geometry 4) proved to create the highest heat transfer rate through the way it produced turbulent air flow. The average Nusselt number of this design was found to be 718.2 and 868.3 for 23.88 and 27.86 m/s respectively. From the calculated data it was found that higher Nusselt numbers were more prone to occur in higher air velocities.

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.

Recent Advances in the Study of Film Cooling on the Gas Turbine Blade

2014 ◽  
Vol 971-973 ◽  
pp. 143-147 ◽  
Author(s):  
Ping Dai ◽  
Shuang Xiu Li
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbines ◽  
High Performance ◽  
Leading Edge ◽  
Development Trend ◽  
Research Progress ◽  
Gas Turbine Blade ◽  
New Generation

The development of a new generation of high performance gas turbine engines requires gas turbines to be operated at very high inlet temperatures, which are much higher than the allowable metal temperatures. Consequently, this necessitates the need for advanced cooling techniques. Among the numerous cooling technologies, the film cooling technology has superior advantages and relatively favorable application prospect. The recent research progress of film cooling techniques for gas turbine blade is reviewed and basic principle of film cooling is also illustrated. Progress on rotor blade and stationary blade of film cooling are introduced. Film cooling development of leading-edge was also generalized. Effect of various factor on cooling effectiveness and effect of the shape of the injection holes on plate film cooling are discussed. In addition, with respect to progress of discharge coefficient is presented. In the last, the future development trend and future investigation direction of film cooling are prospected.

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