{"title":"Numerical assessment of thermal insulation and stress responses in film-cooled turbine vane thermal barrier coatings under CMAS deposition conditions","authors":"","doi":"10.1016/j.surfcoat.2024.131158","DOIUrl":null,"url":null,"abstract":"<div><p>Deposition of CaO-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (CMAS) significantly contributes to the spalling of thermal barrier coatings (TBCs) on turbine vanes. A thorough understanding of the thermodynamic properties during CMAS deposition is critical for advancing the lifetime design of TBCs. This study employs the CMAS gas thermal shock test to determine the deposition characteristics, which were then analyzed using the critical velocity model. The results of this analysis align closely with experimental outcomes. Based on the numerical simulation of the fluid-solid coupling method, we further explored the insulation efficiency and stress distribution in TBCs under CMAS deposition conditions. It was observed that CMAS predominantly accumulates on the pressure side and within the film pores of the vane TBCs, with minimal deposition on the suction side. Such deposition patterns result in an increased overall temperature of the vane, concurrently diminishing the TBCs' insulation efficiency. Specifically, CMAS deposition raised the maximum surface temperature of the vane by 100 K and decreased the peak insulation performance of the TBCs by 16 %. Additionally, the deposition induced higher stresses within both the TBCs and the underlying vane substrate, with a 7 % increase in the maximum principal stresses at the TBC surface and a 6 % increase in the substrate. Consequently, under CMAS deposition conditions, TBCs in regions of low insulation efficiency and high stress on turbine vanes are prone to cracking and subsequent spallation.</p></div>","PeriodicalId":22009,"journal":{"name":"Surface & Coatings Technology","volume":null,"pages":null},"PeriodicalIF":5.3000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Surface & Coatings Technology","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0257897224007898","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, COATINGS & FILMS","Score":null,"Total":0}
引用次数: 0
Abstract
Deposition of CaO-MgO-Al2O3-SiO2 (CMAS) significantly contributes to the spalling of thermal barrier coatings (TBCs) on turbine vanes. A thorough understanding of the thermodynamic properties during CMAS deposition is critical for advancing the lifetime design of TBCs. This study employs the CMAS gas thermal shock test to determine the deposition characteristics, which were then analyzed using the critical velocity model. The results of this analysis align closely with experimental outcomes. Based on the numerical simulation of the fluid-solid coupling method, we further explored the insulation efficiency and stress distribution in TBCs under CMAS deposition conditions. It was observed that CMAS predominantly accumulates on the pressure side and within the film pores of the vane TBCs, with minimal deposition on the suction side. Such deposition patterns result in an increased overall temperature of the vane, concurrently diminishing the TBCs' insulation efficiency. Specifically, CMAS deposition raised the maximum surface temperature of the vane by 100 K and decreased the peak insulation performance of the TBCs by 16 %. Additionally, the deposition induced higher stresses within both the TBCs and the underlying vane substrate, with a 7 % increase in the maximum principal stresses at the TBC surface and a 6 % increase in the substrate. Consequently, under CMAS deposition conditions, TBCs in regions of low insulation efficiency and high stress on turbine vanes are prone to cracking and subsequent spallation.
期刊介绍:
Surface and Coatings Technology is an international archival journal publishing scientific papers on significant developments in surface and interface engineering to modify and improve the surface properties of materials for protection in demanding contact conditions or aggressive environments, or for enhanced functional performance. Contributions range from original scientific articles concerned with fundamental and applied aspects of research or direct applications of metallic, inorganic, organic and composite coatings, to invited reviews of current technology in specific areas. Papers submitted to this journal are expected to be in line with the following aspects in processes, and properties/performance:
A. Processes: Physical and chemical vapour deposition techniques, thermal and plasma spraying, surface modification by directed energy techniques such as ion, electron and laser beams, thermo-chemical treatment, wet chemical and electrochemical processes such as plating, sol-gel coating, anodization, plasma electrolytic oxidation, etc., but excluding painting.
B. Properties/performance: friction performance, wear resistance (e.g., abrasion, erosion, fretting, etc), corrosion and oxidation resistance, thermal protection, diffusion resistance, hydrophilicity/hydrophobicity, and properties relevant to smart materials behaviour and enhanced multifunctional performance for environmental, energy and medical applications, but excluding device aspects.