scholarly journals Investigation of Cooling Performances of a Non-Film-Cooled Turbine Vane Coated with a Thermal Barrier Coating Using Conjugate Heat Transfer

Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 1000 ◽  
Author(s):  
Prasert Prapamonthon ◽  
Soemsak Yooyen ◽  
Suwin Sleesongsom ◽  
Daniele Dipasquale ◽  
Huazhao Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Conjugate Heat Transfer ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Turbine Vane

Analysis of Conjugate Heat Transfer Between Cooling Film and Thermal Barrier Coatings Based on Micro-Structure

2016 ◽  
Author(s):  
Yuzhang Wang ◽  
Jiali Li ◽  
Hongzhao Liu ◽  
Yiwu Weng
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Conjugate Heat Transfer ◽  
Spatial Variations ◽  
Thermal Barrier ◽  
Micro Structure ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Micro Structures

Due to different preparation processes and long term operation, the micro structure of thermal barrier coating is different. The different micro structures have great effect on the thermal insulation properties of thermal barrier coatings and the conjugate heat transfer between the cooling film and thermal barrier coatings. In this work, different micro structures of thermal barrier coating were reconstructed using the scanning electron microscopy (SEM) images of two kinds of real thermal barrier coatings. The developed numerical calculation program based on the lattice Boltzmann method (LBM) was used to analyze the conjugate flow field and heat transfer between cooling film and porous thermal barrier coatings. The results show that the micro structures of thermal barrier coatings have a great influence on the stability of the surface film. Weak spatial variations in fluid velocity appear over the coating surface. The spatial variations in velocity over the layered coatings are larger because of its rough surfaces. The ratio of the vertical velocity to the bulk flow velocity can reach 2.5%. There is obvious vortex flow at the interface of coatings and cooling film, and weak flow in the interior perpendicular pores of the columnar coatings.

THERMAL BARRIER COATING AND TURBULENCE INTENSITY EFFECTS ON LEADING EDGE COOLING USING CONJUGATE HEAT TRANSFER ANALYSIS

2017 ◽  
Vol 41 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Prasert Prapamonthon ◽  
Huazhao Xu ◽  
Zhaoqing Ke ◽  
Wenshuo Yang ◽  
Jianhua Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Conjugate Heat Transfer ◽  
Numerical Study ◽  
Guide Vane ◽  
Leading Edge ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Free Stream Turbulence ◽  
Barrier Coating

This is a numerical study of thermal barrier coating (TBC) and turbulence on leading edge (LE) cooling of a guide vane. Numerical results were carried out using 3D CFD with conjugate heat transfer analysis. Important phenomena were revealed. (1) TBC is effective in the LE region especially when free stream turbulence (Tu) increases. (2) At each Tu, TBC near the hub of the vane provides the most effective protection and at the highest Tu, TBC improves overall cooling effectiveness there by about 25%. (3) Near the exits of film hole, TBC may have negative effect, because of heat transfer impedance from the solid structure into the mixing fluid between mainstream and cooling air emitted from film holes.

Uncertainty Quantification and Conjugate Heat Transfer: A Stochastic Analysis

2012 ◽  
Author(s):  
F. Montomoli ◽  
A. D’Ammaro ◽  
S. Uchida
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Uncertainty Quantification ◽  
Thermal Barrier Coating ◽  
Coating Thickness ◽  
Conjugate Heat Transfer ◽  
Metal Temperature ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Pressure Nozzle

Conjugate Heat Transfer studies are a common method to predict the thermal loading in high pressure nozzles. Despite the accuracy of nowadays tools, it is not clear how to include the uncertainties associated to the turbulence level, the temperature distribution or the thermal barrier coating thickness in the numerical simulations. All these parameters are stochastic even if their value is commonly assumed to be deterministic. For the first time, in this work a stochastic analysis is used to predict the metal temperature in a real high pressure nozzle. The domain is the complete high pressure nozzle of F-type Mitsubishi Heavy Industries gas turbine with impingement, film and trailing edge cooling. The stochastic variations are included by coupling Uncertainty Quantification Methods and Conjugate Heat Transfer. Two Uncertainty Quantification methods have been compared: a Probabilistic Collocation Method (PCM) and a Stochastic Collocation Method (SCM). The stochastic distribution of thermal barrier coating thickness, used in the simulations, has been measured at the midspan. A Gaussian distribution for the turbulence intensity and hot core location has been assumed. By using PCM and SCM, the probability to obtain specific metal temperature at midspan is evaluated. The two methods predict the same distribution of temperature with a maximum difference of 0.6% and the results are compared with the experimental data measured in the real engine. The experimental data are inside the uncertainty band associated to the CFD predictions except near at the trailing edge on the pressure side. This work shows that one of the most important parameters affecting the metal temperature uncertainty is the pitch-wise location of the hot core. Assuming a probability distribution for this location, with a standard deviation of 1.7 degrees, the metal temperature at midspan can change up to 30%. The impact of turbulence level and thermal barrier coating thickness is one order of magnitude less important.

Uncertainty Quantification and Conjugate Heat Transfer: A Stochastic Analysis

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
F. Montomoli ◽  
A. D’Ammaro ◽  
S. Uchida
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Uncertainty Quantification ◽  
Thermal Barrier Coating ◽  
Coating Thickness ◽  
Conjugate Heat Transfer ◽  
Metal Temperature ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Pressure Nozzle

Conjugate heat transfer is gaining acceptance for predicting the thermal loading in high pressure nozzles. Despite the accuracy nowadays of numerical solvers, it is not clear how to include the uncertainties associated to the turbulence level, the temperature distribution, or the thermal barrier coating thickness in the numerical simulations. All these parameters are stochastic even if their value is commonly assumed to be deterministic. For the first time, in this work a stochastic analysis is used to predict the metal temperature in a real high-pressure nozzle. The domain simulated is the high pressure nozzle of an F-type Mitsubishi Heavy Industries gas turbine. The complete coolant system is included: impingement, film, and trailing edge cooling. The stochastic variations are included by coupling uncertainty quantification methods and conjugate heat transfer. Two uncertainty quantification methods have been compared: a probabilistic collocation method (PCM) and a stochastic collocation method (SCM). The stochastic distribution of thermal barrier coating thickness, used in the simulations, has been measured at the midspan. A Gaussian distribution for the turbulence intensity and hot core location has been assumed. By using PCM and SCM, the probability to obtain a specific metal temperature at midspan is evaluated. The two methods predict the same distribution of temperature with a maximum difference of 0.6%, and the results are compared with the experimental data measured in the real engine. The experimental data are inside the uncertainty band associated to the CFD predictions. This work shows that one of the most important parameters affecting the metal temperature uncertainty is the pitch-wise location of the hot core. Assuming a probability distribution for this location, with a standard deviation of 1.7 deg, the metal temperature at midspan can change up to 30%. The impact of turbulence level and thermal barrier coating thickness is 1 order of magnitude less important.

Comparison of Predictions From Conjugate Heat Transfer Analysis of a Film-Cooled Turbine Vane to Experimental Data

2013 ◽  
Author(s):  
Ron-Ho Ni ◽  
William Humber ◽  
George Fan ◽  
John P. Clark ◽  
Richard J. Anthony ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Conjugate Heat Transfer ◽  
Metal Temperature ◽  
Heat Transfer Analysis ◽  
Barrier Coating ◽  
Turbine Vane ◽  
Flux Measurements ◽  
Surface Metal ◽  
Air Force Research Laboratory

Conjugate heat transfer analysis was conducted on a 648 hole film cooled turbine vane using Code Leo and compared to experimental results obtained at the Air Force Research Laboratory Turbine Research Facility. An unstructured mesh with fully resolved film holes for both fluid and solid domains was used to conduct the conjugate heat transfer simulation on a desktop PC with eight cores. Initial heat flux and surface metal temperature predictions showed reasonable agreement with heat flux measurements but under prediction of surface metal temperature values. Root cause analysis was performed, leading to two refinements. First, a thermal barrier coating layer was introduced into the analysis to account for the insulating properties of the Kapton layer used for the heat flux gauges. Second, inlet boundary conditions were updated to more accurately reflect rig measurement conditions. The resulting surface metal temperature predictions showed excellent agreement relative to measured results (+/− 5 degrees K).

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