Short-Duration Measurements and Numerical Simulation of Heat Transfer Along the Suction Side of a Film-Cooled Gas Turbine Blade

1985 ◽  
Vol 107 (4) ◽  
pp. 991-997 ◽  
Author(s):  
C. Camci ◽  
T. Arts
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Suction Side ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Isentropic Compression ◽  
Curvature Effects ◽  
Convex Wall

This paper deals with an experimental investigation of heat transfer across the suction side of a high-pressure, film-cooled gas turbine blade and with an attempt to numerically predict this quantity both with and without film cooling. The measurements were performed in the VKI isentropic compression tube facility under well-simulated gas turbine conditions. Data measured in a stationary frame, with and without film cooling, are presented. The predictions of convective heat transfer, including streamwise curvature effects, are compared with the measurements. A new approach to determine the augmented mixing lengths near the ejection holes on a highly convex wall is discussed and numerical results agree well with experimentally determined heat transfer coefficients in the presence of film cooling.

scholarly journals Detailed Film Cooling Measurements over a Gas Turbine Blade Using a Transient Liquid Crystal Image Technique

2001 ◽  
Vol 7 (6) ◽  
pp. 415-424 ◽  
Author(s):  
Hui Du ◽  
Srinath V. Ekkad ◽  
Je-Chin Han ◽  
C. Pang Lee
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Blowing Ratio ◽  
Image Technique

Detailed heat transfer coefficient and film effectiveness distributions over a gas turbine blade with film cooling are obtained using a transient liquid crystal image technique. The test blade has three rows of film holes on the leading edge and two rows each on the pressure and suction surfaces. A transient liquid crystal technique maps the entire blade midspan region, and helps provide detailed measurements, particularly near the film hole. Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity is5.3×105. Two different coolants (air andCo2) were used to simulate coolant density effect. Coolant blowing ratio was varied between 0.8 and 1.2 for air injection and 0.4–1.2 forCo2injection. Results show that film injection promotes earlier laminar-turbulent boundary layer transition on the suction surface and also enhances local heat transfer coefficients (up to 80%) downstream of injection. An increase in coolant blowing ratio produces higher heat transfer coefficients for both coolants. This effect is stronger immediately downstream of injection holes. Film effectiveness is highest at a blowing ratio of 0.8 for air injection and at a blowing ratio of 1.2 forCo2injection. Such detailed results will help provide insight into the film cooling phenomena on a gas turbine blade.

Heat Transfer Coefficients and Film Cooling Effectiveness on the Squealer Tip of a Gas Turbine Blade

2003 ◽  
Vol 125 (4) ◽  
pp. 648-657 ◽  
Author(s):  
Jae Su Kwak ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Rotor Blade ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Heat Transfer Coefficients ◽  
Blowing Ratio

Experimental investigations were performed to measure the detailed heat transfer coefficients and film cooling effectiveness on the squealer tip of a gas turbine blade in a five-bladed linear cascade. The blade was a two-dimensional model of a first stage gas turbine rotor blade with a profile of the GE-E3 aircraft gas turbine engine rotor blade. The test blade had a squealer (recessed) tip with a 4.22% recess. The blade model was equipped with a single row of film cooling holes on the pressure side near the tip region and the tip surface along the camber line. Hue detection based transient liquid crystals technique was used to measure heat transfer coefficients and film cooling effectiveness. All measurements were done for the three tip gap clearances of 1.0%, 1.5%, and 2.5% of blade span at the two blowing ratios of 1.0 and 2.0. The Reynolds number based on cascade exit velocity and axial chord length was 1.1×106 and the total turning angle of the blade was 97.9 deg. The overall pressure ratio was 1.2 and the inlet and exit Mach numbers were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7%. Results showed that the overall heat transfer coefficients increased with increasing tip gap clearance, but decreased with increasing blowing ratio. However, the overall film cooling effectiveness increased with increasing blowing ratio. Results also showed that the overall film cooling effectiveness increased but heat transfer coefficients decreased for the squealer tip when compared to the plane tip at the same tip gap clearance and blowing ratio conditions.

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.

Unsteady Wake Effect on Film Temperature and Effectiveness Distributions for a Gas Turbine Blade

1999 ◽  
Vol 122 (2) ◽  
pp. 340-347 ◽  
Author(s):  
Shuye Teng ◽  
Dong Kee Sohn ◽  
Je-Chin Han
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Suction Side ◽  
Boundary Layer Transition ◽  
Gas Turbine Blade ◽  
Wake Effect ◽  
Layer Transition ◽  
Film Cooling Effectiveness ◽  
Unsteady Wake

The film effectiveness and coolant jet temperature profile on the suction side of a gas turbine blade were measured using a transient liquid crystal and a cold-wire technique, respectively. The blade has only one row of film holes near the gill hole portion on the suction side of the blade. Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity was 5.3×105. Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. Coolant blowing ratio was varied from 0.6 to 1.2. Wake Strouhal number was kept at 0 and 0.1. Results show that unsteady wake reduces film cooling effectiveness. Results also show that film injection enhances local heat transfer coefficient while the unsteady wake promotes earlier boundary-layer transition. The development of coolant jet temperature profiles could be used to explain the film cooling performance. [S0889-504X(00)00402-5]

Effect of Squealer Geometry Arrangement on a Gas Turbine Blade Tip Heat Transfer

2002 ◽  
Vol 124 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Gm Salam Azad ◽  
Je-Chin Han ◽  
Ronald S. Bunker ◽  
C. Pang Lee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Pressure Ratio ◽  
Suction Side ◽  
Pressure Side ◽  
Gas Turbine Blade ◽  
Blade Tip

This study investigates the effect of a squealer tip geometry arrangement on heat transfer coefficient and static pressure distributions on a gas turbine blade tip in a five-bladed stationary linear cascade. A transient liquid crystal technique is used to obtain detailed heat transfer coefficient distribution. The test blade is a linear model of a tip section of the GE E3 high-pressure turbine first stage rotor blade. Six tip geometry cases are studied: (1) squealer on pressure side, (2) squealer on mid camber line, (3) squealer on suction side, (4) squealer on pressure and suction sides, (5) squealer on pressure side plus mid camber line, and (6) squealer on suction side plus mid camber line. The flow condition during the blowdown tests corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial chord of 1.1×106. Results show that squealer geometry arrangement can change the leakage flow and results in different heat transfer coefficients to the blade tip. A squealer on suction side provides a better benefit compared to that on pressure side or mid camber line. A squealer on mid camber line performs better than that on a pressure side.

Effect of Squealer Geometry Arrangement on Gas Turbine Blade Tip Heat Transfer

2001 ◽  
Author(s):  
Gm Salam Azad ◽  
Je-Chin Han ◽  
Ronald S. Bunker ◽  
C. Pang Lee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Pressure Ratio ◽  
Suction Side ◽  
Pressure Side ◽  
Gas Turbine Blade ◽  
Blade Tip

Abstract This study investigates the effect of a squealer tip geometry arrangement on heat transfer coefficient and static pressure distributions on a gas turbine blade tip in a five-bladed stationary linear cascade. A transient liquid crystal technique is used to obtain detailed heat transfer coefficient distribution. The test blade is a linear model of a tip section of the GE E3 high-pressure turbine first stage rotor blade. Six tip geometry cases are studied: 1) squealer on pressure side, 2) squealer on mid camber line, 3) squealer on suction side, 4) squealer on pressure and suction sides, 5) squealer on pressure side plus mid camber line, and 6) squealer on suction side plus mid camber line. The flow condition corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial chord of 1.1 × 106. Results show that squealer geometry arrangement can change the leakage flow and results in different heat transfer coefficients to the blade tip. A squealer on suction side provides a better benefit compared to that on pressure side or mid camber line. A squealer on mid camber line performs better than that on a pressure side.

Film Cooling of a Gas Turbine Blade

1978 ◽  
Vol 100 (3) ◽  
pp. 476-481 ◽  
Author(s):  
S. Ito ◽  
R. J. Goldstein ◽  
E. R. G. Eckert
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Momentum Flux ◽  
Flux Ratio ◽  
Large Momentum ◽  
Gas Turbine Blade ◽  
Momentum Flux Ratio ◽  
Concave Wall ◽  
Convex Wall

The local film-cooling produced by a row of jets on a gas turbine blade is measured by a mass transfer technique. The density of the secondary fluid is from 0.75 to two times that of the mainflow and the range of the mass flux ratio is from 0.2 to three. The effect of blade-wall curvature on the film-cooling effectiveness is very significant. On the convex wall, a near tangential jet is pushed towards the wall by the static pressure force around the jet. For a small momentum flux ratio, this results in a higher effectiveness compared with that on a flat wall. At a large momentum flux ratio, however, the jet tends to move away from the curved wall because of the effect of inertia of the jet resulting in a smaller effectiveness on the convex wall. On the concave wall, the effects of curvature are the reverse of those described for the convex wall.

Sign in / Sign up

Export Citation Format

Share Document