Wang Jian-Xin, Sun Hong-Tu, Gong Qing-Tao, Li Feng-Xun, Li Zhen-Zhe
School of Business, Ludong University, Shandong 264025, China.
Ulsan Ship and Ocean College, Ludong University, Shandong 264025, P.R. China.
ACS Omega. 2023 Mar 31;8(14):13048-13058. doi: 10.1021/acsomega.3c00307. eCollection 2023 Apr 11.
Thermal barrier coating (TBC) systems are widely adopted in gas turbine blades to improve the thermal efficiency of gas turbine engines. However, TBC failure will happen due to the thermal stress between the different layers of the TBC systems. The traditional two-layer theoretical model only considers TGO (thermally grown oxide) and a substrate in the inner cooling hole with the surface uncoated, which results in poor prediction of the deformations of the TBC systems. It should be mentioned that the effect of TBC is very important because the thickness of TBC is much larger than the TGO thickness. In this study, a new three-layer theoretical model was derived, which is composed of the cylindrical TGO and TBC mounted in the substrate with a circular hole, and the stress and strain of TGO near the cooling hole under the condition of the thermal cycles were calculated. The high temperature characteristics of TGO and the substrate including the high temperature strength and growth ratio were from the experiments. The results show that the strain of the developed three-layer model is irrelevant with increasing number of cycles, which indicates that TBC in the cooling hole significantly inhibits the deformation of TGO near the cooling hole. Therefore, aimed at confirming the feasibility of the three-layer theoretical model, the finite element analysis with coating in the cooling hole and on the surface was carried out with a three-layer axisymmetric model, which proves that the 3-layer theoretical model can predict the deformation trend near the cooling hole.
热障涂层（TBC）系统被广泛应用于燃气轮机叶片，以提高燃气轮机发动机的热效率。然而，由于TBC系统不同层之间的热应力，TBC会发生失效。传统的两层理论模型仅考虑内部冷却孔中未涂层表面的TGO（热生长氧化物）和基体，这导致对TBC系统变形的预测效果不佳。应该指出的是，TBC的影响非常重要，因为TBC的厚度远大于TGO的厚度。在本研究中，推导了一种新的三层理论模型，该模型由安装在带有圆孔的基体中的圆柱形TGO和TBC组成，并计算了热循环条件下冷却孔附近TGO的应力和应变。TGO和基体的高温特性，包括高温强度和生长率，均来自实验。结果表明，所建立的三层模型的应变与循环次数的增加无关，这表明冷却孔中的TBC显著抑制了冷却孔附近TGO的变形。因此，为了证实三层理论模型的可行性，采用三层轴对称模型对冷却孔内和表面有涂层的情况进行了有限元分析，结果证明三层理论模型能够预测冷却孔附近的变形趋势。
