Film Cooling Performance in a Transonic High-pressure Vane: Decoupled Simulation and Conjugate Heat Transfer Analysis

A high-pressure vane equipped with a realistic film-cooling configuration has been studied. The vane is characterized by the presence of multiple rows of fan-shaped holes along pressure and suction side while the leading edge is protected by a showerhead system of cylindrical holes. Steady three-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulations have been performed. A preliminary grid sensitivity analysis with uniform inlet flow has been used to quantify the effect of spatial discretization. Turbulence model has been assessed in comparison with available experimental data. The effects of the relative alignment between combustion chamber and high-pressure vanes are then investigated considering realistic inflow conditions in terms of hot spot and swirl. The inlet profiles used are derived from the EU-funded project TATEF2. Two different clocking positions are considered: the first one where hot spot and swirl core are aligned with passage and the second one where they are aligned with the leading edge. Comparisons between metal temperature distributions obtained from conjugate heat transfer simulations are performed evidencing the role of swirl in determining both the hot streak trajectory within the passage and the coolant redistribution. The leading edge aligned configuration is resulted to be the most problematic in terms of thermal load, leading to increased average and local vane temperature peaks on both suction side and pressure side with respect to the passage aligned case. A strong sensitivity of both injected coolant mass flow and heat removed by heat sink effect has also been highlighted for the showerhead cooling system.

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Conjugate Heat Transfer Analysis to Assess Overall Cooling Effectiveness of High Pressure Turbine Nozzle With Optimized Film Cooling Hole Arrangements

Volume 5A: Heat Transfer ◽

10.1115/gt2019-91194 ◽

2019 ◽

Author(s):

Young Seok Kang ◽

Dong-Ho Rhee ◽

Sanga Lee ◽

Bong Jun Cha

Keyword(s):

Heat Transfer ◽

High Pressure ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Heat Transfer Analysis ◽

Internal Cooling ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness ◽

Baseline Design ◽

Pressure Surface

Abstract Conjugate heat transfer analysis method has been highlighted for predicting heat exchange between fluid domain and solid domain inside high-pressure turbines, which are exposed to very harsh operating conditions. Then it is able to assess the overall cooling effectiveness considering both internal cooling and external film cooling at the cooled turbine design step. In this study, high-pressure turbine nozzles, which have three different film cooling holes arrangements, were numerically simulated with conjugate heat transfer analysis method for predicting overall cooling effectiveness. The film cooling holes distributed over the nozzle pressure surface were optimized by minimizing the peak temperature, temperature deviation. Additional internal cooling components such as pedestals and rectangular rib turbulators were modeled inside the cooling passages for more efficient heat transfer. The real engine conditions were given for boundary conditions to fluid and solid domains for conjugate heat transfer analysis. Hot combustion gas properties such as specific heat at constant pressure and other transport properties were given as functions of temperature. Also, the conductivity of Inconel 718 was also given as a function of temperature to solve the heat equation in the nozzle solid domain. Conjugate heat transfer analysis results showed that optimized designs showed better cooling performance, especially on the pressure surface due to proper staggering and spacing hole-rows compared to the baseline design. The overall cooling performances were offset from the adiabatic film cooling effectiveness. Locally concentrated heat transfer and corresponding high cooling effectiveness region appeared where internal cooling effects were overlapped in the optimized designs. Also, conjugate heat transfer analysis results for the optimized designs showed more uniform contours of the overall cooling effectiveness compared to the baseline design. By varying the coolant mass flow rate, it was observed that pressure surface was more sensitive to the coolant mass flow rate than nozzle leading edge stagnation region and suction surface. The CHT results showed that optimized designs to improve the adiabatic film cooling effectiveness also have better overall cooling effectiveness.

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Clocking Effects of Inlet Nonuniformities in a Fully Cooled High-Pressure Vane: A Conjugate Heat Transfer Analysis

Journal of Turbomachinery ◽

10.1115/1.4031864 ◽

2015 ◽

Vol 138 (2) ◽

Cited By ~ 13

Author(s):

Duccio Griffini ◽

Massimiliano Insinna ◽

Simone Salvadori ◽

Francesco Martelli

Keyword(s):

Heat Transfer ◽

High Pressure ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Cooling System ◽

Hot Spot ◽

Three Dimensional ◽

Leading Edge ◽

Suction Side ◽

Heat Transfer Analysis

A high-pressure vane (HPV) equipped with a realistic film-cooling configuration has been studied. The vane is characterized by the presence of multiple rows of fan-shaped holes along pressure and suction side, while the leading edge (LE) is protected by a showerhead system of cylindrical holes. Steady three-dimensional Reynolds-averaged Navier–Stokes simulations have been performed. A preliminary grid sensitivity analysis with uniform inlet flow has been used to quantify the effect of spatial discretization. Turbulence model has been assessed in comparison with available experimental data. The effects of the relative alignment between combustion chamber and HPVs are then investigated, considering realistic inflow conditions in terms of hot spot and swirl. The inlet profiles used are derived from the EU-funded project TATEF2. Two different clocking positions are considered: the first in which hot spot and swirl core are aligned with passage; and the second in which they are aligned with the LE. Comparisons between metal temperature distributions obtained from conjugate heat transfer (CHT) simulations are performed, evidencing the role of swirl in determining both the hot streak trajectory within the passage and the coolant redistribution. The LE aligned configuration is determined to be the most problematic in terms of thermal load, leading to increased average and local vane temperature peaks on both suction side and pressure side with respect to the passage-aligned case. A strong sensitivity to both injected coolant mass flow and heat removed by heat sink effect has also been highlighted for the showerhead cooling system.

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Conjugate Heat Transfer Analysis of a Film Cooled High-Pressure Turbine Vane Under Realistic Combustor Exit Flow Conditions

Volume 5A: Heat Transfer ◽

10.1115/gt2014-25280 ◽

2014 ◽

Cited By ~ 11

Author(s):

Massimiliano Insinna ◽

Duccio Griffini ◽

Simone Salvadori ◽

Francesco Martelli

Keyword(s):

Heat Transfer ◽

High Pressure ◽

Boundary Conditions ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Heat Transfer Analysis ◽

Annular Combustor ◽

Turbulent Closure ◽

High Pressure Stage ◽

Turbulence Length

In this paper conjugate heat transfer analysis of the cooled vane of the MT1 research high-pressure stage is presented. Inlet boundary conditions (including non-uniform total temperature, non-uniform total pressure, swirl, turbulence intensity and turbulence length scale) are obtained considering the exit flow field of a reactive annular combustor simulator. The combustor model has been designed in order to reproduce data available in literature about exit profiles of real combustion chambers and other combustor simulators. Steady simulations are performed on a hybrid unstructured grid obtained from a grid dependence study. The transitional kT-kL-ω model by Walters and Cokljat is used as turbulent closure. Thermal fields obtained from CHT analysis of the vane considering two different clocking positions with respect to the combustor are compared. Results, including film cooling parameters and High-Pressure Vane aerodynamics, are also compared with a uniform inlet case showing the crucial importance of considering realistic boundary conditions for thermal analysis of turbine components.

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Evaluation of CFD simulations of film cooling performance on a turbine vane including conjugate heat transfer effects

International Journal of Heat and Fluid Flow ◽

10.1016/j.ijheatfluidflow.2014.08.010 ◽

2014 ◽

Vol 50 ◽

pp. 279-286 ◽

Cited By ~ 10

Author(s):

Thomas E. Dyson ◽

David G. Bogard ◽

Sean D. Bradshaw

Keyword(s):

Heat Transfer ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Transfer Effects ◽

Cfd Simulations ◽

Cooling Performance ◽

Turbine Vane ◽

Heat Transfer Effects

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IMPROVING THE FILM COOLING PERFORMANCE OF A TURBINE ENDWALL WITH MULTI-FIDELITY MODELING CONSIDERING CONJUGATE HEAT TRANSFER

Journal of Turbomachinery ◽

10.1115/1.4052018 ◽

2021 ◽

pp. 1-20

Author(s):

Hongyan Bu ◽

Yufeng Yang ◽

Liming Song ◽

Jun Li

Keyword(s):

Heat Transfer ◽

Design Optimization ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Inlet Temperature ◽

High Fidelity ◽

Cooling Performance ◽

Fine Mesh ◽

Film Cooling Holes ◽

Component Temperature

Abstract The gas turbine endwall is bearing extreme thermal loads with the rapid increase of turbine inlet temperature. Therefore, the effective cooling of turbine endwalls is of vital importance for the safe operation of turbines. In the design of endwall cooling layouts, numerical simulations based on conjugate heat transfer (CHT) are drawing more attention as the component temperature can be predicted directly. However, the computation cost of high-fidelity CHT analysis can be high and even prohibitive especially when there are many cases to evaluate such as in the design optimization of cooling layout. In this study, we established a multi-fidelity framework in which the data of low-fidelity CHT analysis was incorporated to help the building of a model that predicts the result of high-fidelity simulation. Based upon this framework, multi-fidelity design optimization of a validated numerical turbine endwall model was carried out. The high and low fidelity data were obtained from the computation of fine mesh and coarse mesh respectively. In the optimization, the positions of the film cooling holes were parameterized and controlled by a shape function. With the help of multi-fidelity modeling and sequentially evaluated designs, the cooling performance of the model endwall was improved efficiently.

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Application of Conjugate Heat Transfer Analysis to Improvement of Cooled Turbine Vane and Blade for Industrial Gas Turbine

Volume 5A: Heat Transfer ◽

10.1115/gt2018-75669 ◽

2018 ◽

Author(s):

Takeshi Horiuchi ◽

Tomoki Taniguchi ◽

Ryozo Tanaka ◽

Masanori Ryu ◽

Masahide Kazari

Keyword(s):

Heat Transfer ◽

Gas Turbine ◽

Conjugate Heat Transfer ◽

Metal Temperature ◽

Heat Transfer Analysis ◽

Estimation Accuracy ◽

Cooling Performance ◽

Measurement Results ◽

Turbine Airfoils ◽

Industrial Gas Turbine

In this paper, the Conjugate Heat Transfer (CHT) analysis, which utilizes commercial software STAR-CCM+ with detailed models and practical mesh size, was performed to the first stage cooled turbine airfoils for an industrial gas turbine produced by Kawasaki Heavy Industries, Ltd. (KHI). First its estimation accuracy was evaluated by comparing with the measurement results obtained with thermal index paint (TIP) and a pyrometer. After the validation of the CHT analysis, the metal temperature distribution was understood with the flow phenomena associated with it from the analysis results. To the parts where the metal temperature is locally high, then, the improvements of the cooling performance were considered with the CHT analysis and their effects were finally confirmed by measuring the metal temperature in the actual engine. The investigation reveals that the CHT analysis, which is validated with measurement results, makes it possible for cooling designers to efficiently improve the cooling performance of turbine airfoils with the adequate estimation accuracy, thus enhancing their durability for the reliability of gas turbines.

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Improving the Film Cooling Performance of a Turbine Endwall With Multi-Fidelity Modeling Considering Conjugate Heat Transfer

10.1115/gt2021-59015 ◽

2021 ◽

Author(s):

Hongyan Bu ◽

Yufeng Yang ◽

Liming Song ◽

Jun Li

Keyword(s):

Heat Transfer ◽

Design Optimization ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Inlet Temperature ◽

High Fidelity ◽

Cooling Performance ◽

Fine Mesh ◽

Film Cooling Holes ◽

Component Temperature

Abstract The gas turbine endwall is bearing extreme thermal loads with the rapid increase of turbine inlet temperature. Therefore, the effective cooling of turbine endwalls is of vital importance for the safe operation of turbines. In the design of endwall cooling layouts, numerical simulations based on conjugate heat transfer (CHT) are drawing more attention as the component temperature can be predicted directly. However, the computation cost of high-fidelity CHT analysis can be high and even prohibitive especially when there are many cases to evaluate such as in the design optimization of cooling layout. In this study, we established a multi-fidelity framework in which the data of low-fidelity CHT analysis was incorporated to help the building of a model that predicts the result of high-fidelity simulation. Based upon this framework, multi-fidelity design optimization of a validated numerical turbine endwall model was carried out. The high and low fidelity data were obtained from the computation of fine mesh and coarse mesh respectively. In the optimization, the positions of the film cooling holes were parameterized and controlled by a shape function. With the help of multi-fidelity modeling and sequentially evaluated designs, the cooling performance of the model endwall was improved efficiently.

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