气膜孔堵塞对凹槽叶顶冷却传热性能的影响  

Effects of Film Cooling Hole Blockage on Cooling and Heat Transfer Performance at Squealer Tip

作　　者：徐柯文 何坤[1] 晏鑫[1] XU Kewen;HE Kun;YAN Xin(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2024年第6期139-152,共14页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(52076165)

摘　　要：采用数值方法,研究了燃气透平叶片气膜孔堵塞条件下凹槽叶顶的冷却传热性能,获得了3种吹风比M=0.5, 1.0, 1.5和不同堵塞比B=0, 0.2, 0.4, 0.6, 0.8条件下的凹槽叶顶的气膜冷却效率和传热系数分布。研究表明:气膜孔堵塞会导致凹槽叶顶气膜冷却性能下降、热负荷升高,堵塞比越大,凹槽叶顶的冷却传热性能越差。气膜孔堵塞显著改变了叶顶区域的流场结构,加剧冷气的抬升效应,导致冷气过早离开凹槽。吹风比是影响堵塞工况下凹槽叶顶冷却传热性能的重要因素,吹风比为1.0、堵塞比为0.8时,凹槽叶顶的面积平均气膜冷却效率相比于未堵塞时下降了64.88%、传热系数上升了13.01%。减小吹风比可以改善小堵塞比工况下的叶顶气膜冷却性能,吹风比为0.5、堵塞比为0.4时,叶顶平均气膜冷却效率仅下降了6.82%,但小吹风比会导致大堵塞比工况下的气膜冷却性能恶化严重,吹风比为0.5、堵塞比为0.8时,平均气膜冷却效率下降了82.09%。增大吹风比,可改善大堵塞比工况下的叶顶气膜冷却性能,吹风比为1.5、堵塞比为0.8条件下叶顶平均气膜冷却效率下降了51.34%、传热系数上升了11.52%。Film cooling and heat transfer performance on the squealer tip with different degrees of cooling-hole blockage are investigated using numerical methods.The film cooling effectiveness and heat transfer coefficient distribution on the squealer tip are obtained under three blowing ratios(M=0.5,1.0,and 1.5)and five different blockage ratios(B=0,0.2,0.4,0.6,and 0.8).The results show that the cooling-hole blockage causes decrease of film cooling effect and increase of thermal load on the squealer tip.The film cooling effect and heat transfer performance on the squealer tip are deteriorated with increasing the blockage ratio.The blockage in film cooling holes significantly alters the flow structures in the squealer tip gap.With cooling-hole blockage,the lift-off effect of coolant in the squealer cavity will be aggravated,resulting in earlier leave of cooling flow from the squealer cavity.Generally,the blowing ratio is an important factor that affects the heat transfer and film cooling effect on the squealer tip under blockage conditions.Compared with the unblocked cases,the area-averaged film cooling effectiveness on the squealer tip decreases by 64.88%,and the heat transfer coefficient increases by 13.01%,at blowing ratio M=1.0 and blockage ratio B=0.8.Reducing the blowing ratio is conducive to the improvement of film cooling effectiveness on the squealer tip with small blockage ratio.The area-averaged film cooling effectiveness on the squealer tip only decreases by 6.82%at blowing ratio M=0.5 and blocking ratio B=0.4.However,in the case of small blow ratio,for example M=0.5,the film cooling effect on the squealer tip is deteriorated significantly under the condition of large blockage ratio.At blowing ratio M=0.5 and blocking ratio B=0.8,the area-averaged film cooling effectiveness on the squealer tip decreases by 82.09%compared with the unblocked case.The increase in blowing ratio can improve the film cooling effect on the squealer tip with large blockage ratio.Compared with the unblocked case,the area-averaged film c

关 键 词：燃气透平 凹槽叶顶 气膜孔堵塞 气膜冷却 传热 吹风比 

分 类 号：TK474.7[动力工程及工程热物理—动力机械及工程]