| 摘要: |
| 基于CFD模拟获得的气膜冷却涡轮导叶不均匀温度场，考虑TGO热生长增厚和合金材料的塑性和蠕变行为，对涂层热应力进行了模拟。结果表明，高温区域出现在叶盆和叶背中后部，以及叶栅入口处端壁边缘，涂层使得叶身处合金材料最高温度下降了30℃。在高温工作初期，涂层热应力集中范围更广，易发生早期开裂，而随着高温时间累积，合金材料的蠕变和塑性行为减小了涂层及合金的应力集中范围，并在200~400 h内趋于稳定。TC在叶身处的应力集中区出现在邻近尾缘区域、叶背最大曲率处，以及进气边靠近上下端壁的气膜孔区域；在端壁处的应力集中区初期主要出现在叶栅入口处的进气侧边缘和上端壁气膜孔区域，高温工作时间累积后仅集中在上端壁气膜孔区域。TGO热生长区域应力集中明显，400 h后厚度达到4.79 μm，易诱发涂层剥落。 |
| 关键词: 热障涂层 热应力 气膜冷却 涡轮导叶 数值模拟 |
| DOI：10.11933/j.issn.1007-9289.20171116002 |
| 分类号:TG174.442 |
| 基金项目:国家自然科学基金（11305266） |
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| Numerical Modeling of Thermal Stress of Thermal Barrier Coatings on a Turbine Vane with Film Cooling Structure |
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LIU Jian-hua1, LIU Yong-bao1, LIU Li2, HE Xing1
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1.College of Power Engineering, Naval University of Engineering, Wuhan 430033;2.College of Physics Science and Engineering Technology, Yichun University, Yichun 336000, Jiangxi
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| Abstract: |
| Based on the non-homogenous temperature field of a film cooling turbine vane, the thermal stress of coatings was modeled considering the thermally growing of oxidation and plastic and creep behavior of the alloy. The results show that the high temperature zones are in the posterior of the suction side and pressure side, as well as the edge of the endwalls near the cascade inlet. The coatings provide a 30℃ decline of the maximum temperature of the alloy in the body of the vane. At the beginning, thermal stresses concentrate in larger area in the coatings and maybe more prone to induce early crack. However, the plasticity and creep behavior of the alloy release the thermal stresses of the coatings and alloy with the working time accumulation. The thermal stresses reach stable in 200-400 h. In the body of the vane, the thermal stresses of TC concentrate in the zones nearby the tailing edge, the zones with max curvature at the suction side, and the zones at the leading edge but adjacent to the endwalls. In the endwalls, the stress first concentrates in the zones near the cascade inlet and the zones near the film cooling holes at the upper endwall. However, the stress only concentrates in the zones near the film cooling holes at the upper endwall with the working time accumulation. In the thermally growing zones, TGO thickness reaches 4.79 μm after 400 h, which results in intensive thermal stresses and maybe trigger spallation. |
| Key words: thermal barrier coatings thermal stress film cooling turbine vane numerical modeling |
