肋角度对气膜冷却特性的影响  

Effect of rib orientation on film cooling performance

作　　者：骆剑霞 朱惠人[1] 刘存良[1] 贾广森[1] 

机构地区：[1]西北工业大学动力与能源学院,西安710072

出　　处：《航空动力学报》2014年第7期1615-1622,共8页Journal of Aerospace Power

基　　金：国家重点基础研究发展计划(2013CB035702);国家自然科学基金(51306152)

摘　　要：在光滑二次流通道的基础上,分析对比了两种带肋通道(135°肋和45°肋)对气膜冷却特性的影响.采用瞬态液晶测试技术获得了气膜孔下游表面传热系数比与气膜冷却效率分布.使用Fluent软件RANS数值方法对相应结构进行了数值模拟,并使用了realizable k-ε湍流模型.光滑二次流通道模型中,气膜孔内流线呈螺旋状分布,导致较大的孔内速度分离与流动损失.冷气射流分成两部分,其中一股形成一对偏斜的对转涡.135°肋结构中,二次流通道上部分的旋转涡为顺时针方向,使得气流易于流入气膜孔,气膜孔内流线呈直线分布.45°肋结构中,二次流通道上部分旋转涡为逆时针方向,增强了气膜孔内旋转涡.45°肋结构中冷气流入气膜孔之后的流动结构与光滑二次流通道结构相似.135°肋结构气膜冷却效率最大而表面传热系数比最低.Based on the smooth secondary flow crossflow channel case,two ribbed channels（135 °ribs and 45° ribs）were compared to find out the orientation effect on film cooling performances.The heat transfer coefficient ratio and local film cooling effectiveness were measured by a transient liquid crystal technique.Reynolds averaged Navier Stokes（RANS）simulations with realizable k-εturbulence model and enhanced wall treatment were performed using a commercial code Fluent.In the smooth secondary flow channel case,a helical motion of secondary flow was observed in the film hole,and this motion induced strong velocity separation and flow loss.The cooling air jet was divided into two parts,one consisting of a pair of skewed vortices.In the 135° ribs case,the vortex in the upper half region of the secondary flow channel rotates clockwise,inducing the coolant much easier to flow into the film hole,and straight stream lines in film hole are observed in this case.In the 45° ribs case,the vortex close to the film hole rotates counter clockwise,which enhances the vortices in the film hole.Flowing into the film hole,the flow structure of the coolant in the 45° ribs case is similar with the smooth crossflow channel case.The highest film cooling effectiveness and lowest heat transfer coefficient ratio is observed in the 135° ribs case.

关 键 词：横流 气膜孔 流动结构 对转涡 气膜冷却效率 表面传热系数比 

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]