Effect of RANS-Type Turbulence Models on Adiabatic Film Cooling Effectiveness over a Scaled Up Gas Turbine Blade Leading Edge Surface

Abstract In this work, the area-averaged film cooling effectiveness (AAFCE) on a gas turbine blade leading edge was predicted by employing an artificial neural network (ANN) using as input variables: hole diameter, injection angle, blowing ratio, hole and columns pitch. The database used to train the network was built using computational fluid dynamics (CFD) based on a two level full factorial design of experiments. The CFD numerical model was validated with an experimental rig, where a first stage blade of a gas turbine was represented by a cylindrical specimen. The ANN architecture was composed of three layers with four neurons in hidden layer and Levenberg-Marquardt was selected as ANN optimization algorithm. The AAFCE was successfully predicted by the ANN with a regression coefficient R2<0.99 and a root mean square error RMSE=0.0038. The ANN weight coefficients were used to estimate the relative importance of the input parameters. Blowing ratio was the most influential parameter with relative importance of 40.36 % followed by hole diameter. Additionally, by using the ANN model, the relationship between input parameters was analyzed.

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Effect of Shaped-Hole on Film Cooling Effectiveness of Gas Turbine Blade

10th International Energy Conversion Engineering Conference ◽

10.2514/6.2012-3986 ◽

2012 ◽

Author(s):

Eslam Abdelghany ◽

Ahmed Alsayed ◽

Mahmoud Fouad ◽

Essam Khalil

Keyword(s):

Gas Turbine ◽

Turbine Blade ◽

Film Cooling ◽

Gas Turbine Blade ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness ◽

Shaped Hole

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Numerical Analysis on the Leading Edge Film Cooling of Bifurcation Holes for Gas Turbine Blade

ASME 2021 Heat Transfer Summer Conference ◽

10.1115/ht2021-62615 ◽

2021 ◽

Author(s):

Zhonghao Tang ◽

Gongnan Xie ◽

Honglin Li ◽

Wenjing Gao ◽

Chunlong Tan ◽

...

Keyword(s):

Turbine Blade ◽

Film Cooling ◽

Turbulence Models ◽

Leading Edge ◽

Spanwise Direction ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness ◽

Blowing Ratio ◽

Cylindrical Holes ◽

Lift Off

Abstract Film cooling performance of the cylindrical film holes and the bifurcated film holes on the leading edge model of the turbine blade are investigated in this paper. The suitability of different turbulence models to predict local and average film cooling effectiveness is validated by comparing with available experimental results. Three rows of holes are arranged in a semi-cylindrical model to simulate the leading edge of the turbine blade. Four different film cooling structures (including a cylindrical film holes and other three different bifurcated film holes) and four different blowing ratios are studied in detail. The results show that the film jets lift off gradually in the leading edge area as the blowing ratio increases. And the trajectory of the film jets gradually deviate from the mainstream direction to the spanwise direction. The cylindrical film holes and vertical bifurcated film holes have better film cooling effectiveness at low blowing ratio while the other two transverse bifurcated film holes have better film cooling effectiveness at high blowing ratio. And the film cooling effectiveness of the transverse bifurcated film holes increase with the increasing the blowing ratio. Additionally, the advantage of transverse bifurcated holes in film cooling effectiveness is more obvious in the downstream region relative to the cylindrical holes. The Area-Average film cooling effectiveness of transverse bifurcated film holes is 38% higher than that of cylindrical holes when blowing ratio is 2.

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Improvement of Film Cooling Effectiveness in the Gas Turbine Endwall by Use of Optimization Framework

Volume 3B: Fluid Applications and Systems ◽

10.1115/ajkfluids2019-5368 ◽

2019 ◽

Author(s):

Daisuke Hata ◽

Kazuto Kakio ◽

Yutaka Kawata ◽

Masahiro Miyabe

Keyword(s):

Pressure Gradient ◽

Gas Turbine ◽

Turbine Blade ◽

Film Cooling ◽

Leading Edge ◽

Horseshoe Vortex ◽

Combined Cycle ◽

Inlet Temperature ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness

Abstract Recently, the number of gas turbine combined cycle plants is rapidly increasing in substitution of nuclear power plants. The turbine inlet temperature (TIT) is constantly being increased in order to achieve higher effectiveness. Therefore, the improvement of the cooling technology for high temperature gas turbine blades is one of the most important issue to be solved. In a gas turbine, the main flow impinging at the leading edge of the turbine blade generates a so called horseshoe vortex by the interaction of its boundary layer and generated pressure gradient at the leading edge. The pressure surface leg of this horseshoe vortex crosses the passage and reaches the blade suction surface, driven by the pressure gradient existing between two consecutive blades. In addition, this pressure gradient generates a cross-flow along the endwall. This all results into a very complex flow field in proximity of the endwall. For this reason, burnouts tend to occur at a specific position in the vicinity of the leading edge. In this research, a methodology to cool the endwall of the turbine blade by means of film cooling jets from the blade surface and the endwall is proposed. The cooling performance is investigated using the transient thermography method. CFD analysis is also conducted to investigate the phenomena occurring at the endwall and calculate the film cooling effectiveness.

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Simulation Film Cooling in the Leading Edge Region of a Turbine Blade (Trench Effect on Film Effectiveness from Cylinder in Crossflow)

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.554.317 ◽

2014 ◽

Vol 554 ◽

pp. 317-321

Author(s):

Mohamad Rasidi Bin Pairan ◽

Norzelawati Binti Asmuin ◽

Hamidon bin Salleh

Keyword(s):

Gas Turbine ◽

Turbine Blade ◽

Film Cooling ◽

Leading Edge ◽

Edge Region ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness ◽

Blowing Ratio ◽

Hot Gas ◽

Cooling Technique

Film cooling is one of the cooling techniques applied to the turbine blade. Gas turbine used film cooling technique to protect turbine blade from directly expose to the hot gas to avoid the blade from defect. The focus of this investigation is to investigate the effect of embedded three difference depth of trench at coolant holes geometry. Comparisons are made at four difference blowing ratios which are 1.0, 1.25 and 1.5. Three configuration leading edge with depth Case A (0.0125D), Case B (0.0350D) and Case C (0.713D) were compared to leading edge without trench. Result shows that as blowing ratio increased from 1.0 to 1.25, the film cooling effectiveness is increase for leading edge without trench and also for all cases. However when the blowing ratio is increase to 1.5, film cooling effectiveness is decrease for all cases. Overall the Case B with blowing ratio 1.25 has the best film cooling effectiveness with significant improvement compared to leading edge without trench and with trench Case A and Case C.

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