紧凑凸肋通道对尾缘劈缝气膜冷却特性的影响  

Influence of compact-ribbed passage on trailing-edge cutback film cooling performance

作　　者：叶林 刘存良[1,2] 朱安冬 周天亮 YE Lin;LIU Cunliang;ZHU Andong;ZHOU Tianliang(School of Power and Energy,Northwestern Polytechnical University,Xi'an 710072,China;Shaanxi Key Laboratory of Thermal Sciences in Aero-engine System,Northwestern Polytechnical University,Xi'an 710129,China)

机构地区：[1]西北工业大学动力与能源学院,西安710072 [2]西北工业大学陕西省航空动力系统热科学重点实验室,西安710129

出　　处：《航空学报》2022年第3期167-180,共14页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(51776173);陕西省杰出青年科学基金(2021JC-11)。

摘　　要：以稳态压敏漆技术和瞬态热色液晶技术为测量方法,实验研究了尾缘区域凸肋内冷供气通道对外部气膜冷却特性的影响,详细对比分析了直肋间距和吹风比对尾缘劈缝扩张表面的气膜冷却效率、对流换热系数和劈缝流量系数的影响,并引入热流密度比来衡量对比紧凑凸肋通道对劈缝表面的综合冷却效率增强性能。实验结果表明:劈缝流量系数受吹风比的影响较小,随肋间距的增大而减小;凸肋通道明显加强了射流的混乱程度,导致其与主流掺混程度加剧,降低了劈缝表面远下游区域的气膜冷却效率,小肋间距结构气膜冷却效率略高于大肋间距结构,随着吹风比的增大,凸肋通道结构与基准结构的气膜冷却效率差异减小;凸肋通道结构可提升基准结构缝出口区域的低换热性能,尤其对于小肋间距结构,大吹风比时,缝出口的换热核心区沿流向延伸效果增强;具有小肋间距的凸肋通道对尾缘劈缝的综合冷却性能有促进作用,其中肋间距p/h=4结构可提升15%~20%的综合冷却性能,而大肋间距结构明显降低了基准结构的综合冷却性能。The influence of the coolant convex-ribbed passage in the trailing-edge internal region on the external film cooling characteristics is experimentally studied,using the steady pressure sensitive paint technology and transient thermochromic liquid crystal technology as the measurement methods.The effects of the straight-rib pitch and the blowing ratio on the film cooling effectiveness and convective heat transfer coefficient of the expanded trailing-edge cutback surface as well as the cutback discharge coefficient are analyzed,and the heat flux ratio introduced to evaluate the enhancement effect on the comprehensive cooling effectiveness of the compact-ribbed cases by comparing with the baseline case.The experimental results show that the cutback discharge coefficient is less affected by the blowing ratio and decreases with the increase of the rib-pitch.The convexity of the jet flow is clearly enhanced by the convex-ribbed passage,aggravating the mixing degree with the mainstream,and reducing the film cooling effectiveness in the far-downstream region of the cutback surface.The film cooling effectiveness of the ribbed case with a small rib-pitch is slightly higher than that of the case with a large rib-pitch.With the increase of the blowing ratio,the difference of the film cooling effectiveness between the cases with convex ribs and the baseline case decreases.The compact-ribbed passage can improve the heat transfer performance of the region near the slot exit,particularly for the cases with the small rib-pitch.At a high blowing ratio,the core heat transfer area near the slot exit extends along the flow direction.The convex-ribbed passage with a small rib-pitch can promote the comprehensive cooling performance of the trailing edge cutback,among which the case with rib-pitch p/h=4 improves the comprehensive cooling performance by 15%-20%,while the large rib-pitch cases significantly reduce the comprehensive cooling performance compared with the baseline case.

关 键 词：涡轮叶片尾缘 肋间距 直肋 气膜冷却 压力敏感漆 瞬态热色液晶 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]