南京航空航天大学学报  2016, Vol. 48 Issue (3): 326-333 PDF

1. 南京航空航天大学能源与动力学院，江苏省航空动力系统重点实验室，南京，210016 ;
2. 先进航空发动机协同创新中心，北京，100191 ;
3. 中国航空工业集团公司中国燃气涡轮研究院,成都，610500

Experimental Study on eat Transfer Coefficient of Typical Irregular Cooling Configuration in Double-Deck Turbine Guide Vane
Tu Zecan1, Mao Junkui1,2, Su Yunliang3, Guo Wen3
1. College of Energy and Power Engineering,Nanjing University of Aeronautics&Astronautics,Jiangsu Province Key Laboratory of Aerospace Power System,Nanjing,210016,China ;
2. Collaborative Innovation Center for Advanced Aero-Engine,Beijing,100191,China ;
3. China Gas Turbine Establishment,Aviation Industry Corporation of China,Chengdu,610500,China
Abstract: Cooling structures with playground and oval section are concluded according to the real internal geometry of double-decker turbine guide vane. Experiments are carried out to investigate heat transfer coefficient of hybrid cooling configuration applied in those cooling structures. The influences of coolant Reynolds number,outflow of the film cooling,relative position of impingement holes and film holes on heat transfer characteristics are analyzed in details. There exist periodic peaks and troughs of local heat transfer coefficient due to the impingement. The heat transfer upstream is weakened because of the coolant suction of film outflow,while it can also result in some heat transfer enhancement in the very near region around film hole. It is also found that the performance of hybrid cooling structure increases with the increasing of inlet Reynolds number. Experimental results show that the cooling configuration affects heat transfer coefficient greatly and the rules are complicated. For the cooling configuration with playground section,higher cooling performance can be achieved when film holes are arrayed with jet holes sequentially. In the cases of oval section,higher cooling performance is gotten when the impingement holes and the film holes are staggered.
Key words: propulsion system     jet impingement     film cooling     heat transfer     irregular cooling configuration

1 研究模型及实验系统 1.1 研究模型和实验件设计

 图 1 涡轮叶片内部冷却结构示意图 Figure 1 Schematic of hybrid cooling configuration

 图 2 冲击孔和气膜孔相对位置示意图 Figure 2 Schematic of relative location among impingement holes and film holes

 图 3 实验件安装示意图及照片 Figure 3 Installation instruction and photos of test piece

 图 4 温度测点及加热膜位置示意图 Figure 4 Locations of thermocouples and heated foils

1.2 实验系统和实验工况

 图 5 实验系统示意图 Figure 5 Diagram of experimental system

1.3 实验数据处理

 $Nu=\frac{\left( Q-{{Q}_{loss}} \right)D}{\left( {{T}_{w}}-{{T}_{in}} \right)A{{\lambda }_{sir}}}$ (1)
 ${{Q}_{loss}}={{Q}_{con}}+{{Q}_{rad}}$ (2)
 ${{Q}_{con}}=\lambda A\left( {{T}_{w}}-T{{'}_{w}} \right)/\delta$ (3)
 ${{Q}_{rad}}=\varepsilon \sigma A\left( T_{\mathsf{w}}^{4}-T_{b}^{4} \right)$ (4)

2 实验结果及分析 2.1 冲击靶面的基本换热特性

 图 6 冲击靶面Line 2和Line 5上的Nu数分布 Figure 6 Distribution of Nu on Line 2 and Line 5

2.2 通道截面形状不同时Re数的影响

 图 7 Re数对冲击靶面换热特性的影响 Figure 7 Influences of Re number on heat transfer coefficient

2.3 冲击孔和气膜孔相对位置的影响

 图 8 冲击孔和气膜孔相对位置对冲击靶面换热特性的影响 Figure 8 Influences of relative location between impingement holes and film holes on heat transfer coefficient

 图 9 操场形通道中截面的流线图 Figure 9 Streamline picture of middle section of playground channel

2.4 通道截面形状的影响

 图 10 通道截面形状对冲击靶面换热特性的影响 Figure 10 Influences of cooling configuration on heat transfer coefficient

 图 11 各因素对平均Nuavg数的综合影响 Figure 11 Average heat transfer coefficient affected by different parameters

3 结论

(1) 异形冷却结构通道内，冲击靶面上的局部Nu数呈中心对称的波浪形分布，并且气膜孔上游的局部强化换热整体要低于下游，只有在靠近通道中心区域气膜孔上游的局部强化换热效果略高于下游。

(2) 随着进口Re数的增加，无论是操场形还是椭圆形冷却结构，冲击靶面换热效果都会加强，并且波浪状的局部Nu数分布规律基本保持不变。

(3) 截面形状不同的通道换热特性规律不同，通道截面形状、冲击孔和气膜孔相对位置对冲击靶面换热特性的影响呈现交织的特性。对于操场形通道,冲击孔和气膜孔顺排时冷却效果较好；对于椭圆形冷却通道，冲击孔和气膜孔错排时冷却效果较好。

(4) 在进口Re数相同的情况下，通道截面为椭圆形，冲击孔和气膜孔之间为错排时，冲击靶面的换热效果最佳。