Influence of hole blockage caused by thermal barrier coatings on the turbine vane endwall film cooling performance

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-10-21 DOI:10.1016/j.ijthermalsci.2024.109491

Kun Du , Xiangpeng Pei , Cunliang Liu , Bengt Sunden

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引用次数: 0

Abstract

Thermal barrier coating (TBC) is extensively employed to protect hot components in modern gas turbines due to its high thermal resistance. Laser spraying is used to apply ceramic coating powder onto the target surface. However, when coating the junction region between the endwall and vane, the angle of the sprayer cannot face the surface directly. As a result, excessive spraying in a specific direction will result in hole blockages. Such blockages can disrupt cooling jet outflow, impacting downstream film cooling performance. This study investigated the adiabatic effectiveness of turbine nozzle guide vane endwalls, considering hole blockages. The experiments utilizing pressure sensitive paint (PSP) technique and simulations were both conducted, and the numerical turbulence model was validated. For a turbine cascade vane endwall, the blockage mainly occurred on the film holes near the boundary. These blockages significantly altered film flow direction, and increased the cooling jet momentum. For the endwall with cylindrical holes, the impact of blockages on the endwall cooling performance varied with blowing ratios. For the endwall with fan-shaped holes, blockages enhanced the cooling performance. In contrast, blockages reduced the cooling performance of endwall with converging slot holes.

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隔热涂层造成的孔洞堵塞对涡轮叶片端壁薄膜冷却性能的影响

热障涂层（TBC）具有高耐热性，被广泛用于保护现代燃气轮机中的高温部件。采用激光喷涂技术将陶瓷涂层粉末喷涂到目标表面。然而，在对端壁和叶片之间的交界区域进行喷涂时，喷涂器的角度不能直接面对表面。因此，向特定方向过度喷涂会导致孔洞堵塞。这种堵塞会破坏冷却射流的流出，影响下游薄膜的冷却性能。考虑到孔堵塞问题，本研究对涡轮喷嘴导叶端壁的绝热效果进行了研究。利用压敏涂料（PSP）技术进行了实验和模拟，并对数值湍流模型进行了验证。对于涡轮级联叶片端壁，堵塞主要发生在边界附近的薄膜孔上。这些堵塞明显改变了薄膜的流动方向，并增加了冷却射流的动量。对于带圆柱孔的端壁，阻塞对端壁冷却性能的影响随吹气比的变化而变化。对于带扇形孔的内壁，堵塞会提高冷却性能。相反，堵塞物降低了带有汇聚槽孔的内壁的冷却性能。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.