Optimum Trailing Edge Ejection for Cooled Gas Turbine Blades

1989 ◽  
Vol 111 (4) ◽  
pp. 510-514 ◽  
Author(s):  
T. Schobeiri
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Velocity Ratio ◽  
Turbine Blades ◽  
Slot Width ◽  
Width Ratio ◽  
Ejection Velocity ◽  
Trailing Edge ◽  
Gas Turbine Blades ◽  
Mixing Losses

The effect of trailing edge ejection on the flow downstream of a cooled gas turbine blade is investigated. Parameters that affect the mixing losses and therefore the efficiency of cooled blades are the ejection velocity ratio, the cooling mass flow ratio, the slot-width ratio, and the ejection angle. For ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream to the cooled blade. For given cooling mass flow ratios, optimum slot-width/trailing edge ratios are found, which correspond to the minimum mixing loss coefficients.

Optimization of Trailing Edge Ejection Mixing Losses: A Theoretical and Experimental Study

1999 ◽  
Vol 121 (1) ◽  
pp. 118-125 ◽  
Author(s):  
M. T. Schobeiri ◽  
K. Pappu
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Mass Flow ◽  
Velocity Ratio ◽  
Turbine Blades ◽  
Ejection Velocity ◽  
Trailing Edge ◽  
Gas Turbine Blades ◽  
Flow Deflection ◽  
Mixing Losses

The aerodynamic effects of trailing edge ejection on mixing losses downstream of cooled gas turbine blades were experimentally investigated and compared with an already existing one-dimensional theory by Schobeiri (1989). The significant parameters determining the mixing losses and, therefore, the efficiency of cooled blades, are the ejection velocity ratio, the cooling mass flow ratio, the temperature ratio, the slot thickness ratio, and the ejection flow angle. To cover a broad range of representative turbine blade geometry and flow deflections, a General Electric power generation gas turbine blade with a high flow deflection and a NASA-turbine blade with intermediate flow deflection and different thickness distributions were experimentally investigated and compared with the existing theory. Comprehensive experimental investigations show that for the ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream of the cooled gas turbine blade to a minimum, which is in agreement with the theory. For the given cooling mass flow ratios that are dictated by the heat transfer requirements, optimum slot thickness to trailing edge thickness ratios are found, which correspond to the minimum mixing loss coefficients. The results allow the turbine aerodynamicist to minimize the mixing losses and to increase the efficiency of cooled gas turbine blades.

scholarly journals Optimization of Trailing Edge Ejection Mixing Losses: A Theoretical and Experimental Study

1997 ◽  
Author(s):  
K. R. Pappu ◽  
M. T. Schobeiri
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Mass Flow ◽  
Velocity Ratio ◽  
Turbine Blades ◽  
Ejection Velocity ◽  
Trailing Edge ◽  
Gas Turbine Blades ◽  
Flow Deflection ◽  
Mixing Losses

The aerodynamic effects of trailing edge ejection on mixing losses downstream of cooled gas turbine blades were experimentally investigated and compared with an already existing one-dimensional theory by Schobeiri (1989). The significant parameters determining the mixing losses and therefore the efficiency of cooled blades are the ejection velocity ratio, the cooling mass flow ratio, the temperature ratio, the slot thickness ratio and the ejection flow angle. To cover a broad range of representative turbine blade geometry and flow deflections, a General Electric power generation gas turbine blade with high flow deflection and a NASA-turbine blade with intermediate flow deflection and different thickness distributions were experimentally investigated and compared with the existing theory. Comprehensive experimental investigations show that for the ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream of the cooled gas turbine blade to a minimum which is in agreement with the theory. For the given cooling mass flow ratios that are dictated by the heat transfer requirements, optimum slot thickness to trailing edge thickness ratios are found, which correspond to the minimum mixing loss coefficients. The results allow the turbine aerodynamicist to minimize the mixing losses and to increase the efficiency of cooled gas turbine blades.

Experimental Investigation of Film Cooling With Ejection From a Row of Holes for the Application to Gas Turbine Blades

1975 ◽  
Vol 97 (1) ◽  
pp. 21-27 ◽  
Author(s):  
C. Liess
Keyword(s):  
Boundary Layer ◽  
Gas Turbine ◽  
Velocity Ratio ◽  
Turbine Blades ◽  
Main Flow ◽  
Adiabatic Wall ◽  
Lateral Direction ◽  
Gas Turbine Blades ◽  
Flow Boundary ◽  
Displacement Thickness

The adiabatic wall effectiveness and the heat transfer coefficient is determined experimentally on a flat plate downstream of a row of inclined circular ejection holes. The measuring technique provides local values in downstream direction and averaged values in lateral direction. The ejection geometry is kept constant, i.e., ejection angle β = 35 deg, spacing to diameter ratio of ejection holes s/d = 3. The range of flow parameters corresponds closely to the conditions encountered on gas turbine blades. The main flow Mach number varies from 0.3 to 0.9, the mass velocity ratio from 0.1 to 2.0. Two favorable pressure gradients in the main flow are applied and several ratios of main flow boundary layer displacement thickness to ejection hole diameter. The main flow boundary layer upstream of the ejection is laminar and turbulent.

Numerical Predictions of Three-Dimensional Unsteady Turbulent Film-Cooling for Trailing Edge of Gas-Turbine Blade Using Large Eddy Simulation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Ahmed Khalil ◽  
Hatem Kayed ◽  
Abdallah Hanafi ◽  
Medhat Nemitallah ◽  
Mohamed Habib
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Trailing Edge ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Gas Turbine Blades ◽  
Blowing Ratio ◽  
Eddy Simulation

This work investigates the performance of film-cooling on trailing edge of gas turbine blades using unsteady three-dimensional numerical model adopting large eddy simulation (LES) turbulence scheme in a low Mach number flow regime. This study is concerned with the scaling parameters affecting effectiveness and heat transfer performance on the trailing edge, as a critical design parameter, of gas turbine blades. Simulations were performed using ANSYS-fluentworkbench 17.2. High quality mesh was adapted, whereas the size of cells adjacent to the wall was optimized carefully to sufficiently resolve the boundary layer to obtain insight predictions of the film-cooling effectiveness on a flat plate downstream the slot opening. Blowing ratio, density ratio, Reynolds number, and the turbulence intensity of the mainstream and coolant flow are optimally examined against the film-cooling effectiveness. The predicted results showed a great agreement when compared with the experiments. The results show a distinctive behavior of the cooling effectiveness with blowing ratio variation as it has a dip in vicinity of unity which is explained by the behavior of the vortex entrainment and momentum of coolant flow. The negative effect of the turbulence intensity on the cooling effectiveness is demonstrated as well.

UDIMET L-605

Alloy Digest ◽  
2004 ◽  
Vol 53 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Gas Turbine ◽  
Oxidation Resistance ◽  
Turbine Blades ◽  
Heat Treating ◽  
Gas Turbine Blades ◽  
Temperature Performance

Abstract Udimet L-605 is a high-temperature aerospace alloy with excellent strength and oxidation resistance. It is used in applications such as gas turbine blades and combustion area parts. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: CO-109. Producer or source: Special Metals Corporation.

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