计及机匣相对运动的涡轮叶片叶顶凹槽流动研究

杜金霖; 邹正平; 黄霖; 轩笠铭; 王元鹏

doi:10.11729/syltlx20200073

计及机匣相对运动的涡轮叶片叶顶凹槽流动研究

杜金霖^1,,
邹正平^{1, 2, ,},
黄霖¹,
轩笠铭¹,
王元鹏¹

1.
北京航空航天大学能源与动力工程学院, 航空发动机气动热力国防科技重点实验室, 北京 100191
2.
北京航空航天大学航空发动机研究院, 北京 102206

基金项目:

国家自然科学基金 51676005

详细信息

作者简介:
杜金霖(1997-), 男, 河南泌阳人, 硕士研究生。研究方向: 涡轮叶尖泄漏流动。通信地址: 北京市海淀区学院路37号北京航空航天大学能源与动力工程学院(100191)。E-mail: djlindy@126.com

通讯作者:
邹正平, E-mail: zouzhengping@buaa.edu.cn

中图分类号: V211.7
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出版历程
- 收稿日期: 2020-06-09
- 修回日期: 2020-08-03
- 刊出日期: 2021-03-31

Experimental and numerical study of squealer tip flow field considering relative casing motion

1.
National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics, School of Energy & Power Engineering, Beihang University, Beijing 100191, China
2.
Research Institute of Aero-Engine, Beihang University, Beijing 102206, China

摘要

摘要: 叶尖泄漏流是造成航空发动机涡轮内部损失的重要因素，而凹槽叶尖是控制叶尖泄漏流的有效手段，准确了解凹槽内的流动结构有助于认识泄漏流的流动规律和泄漏损失的物理机制。为了详细研究考虑机匣相对运动时叶尖凹槽腔内流动结构变化及其对泄漏流的影响，搭建了可模拟机匣相对运动的低速平面叶栅实验台，该实验台可以进行不同叶型、不同叶顶结构以及不同攻角等因素的研究。采用PIV技术设计了一种可以在机匣相对运动时对凹槽腔内流动进行测量的可视化测量方法。使用该测量方法捕捉到了凹槽腔内旋涡的流动结构，结合数值结果分析了不同机匣运动状态下凹槽腔内流动结构的演化过程，结果表明：刮削涡在凹槽腔内形成类似气动篦齿的封严效果，减小了间隙出口有效流通面积，降低了凹槽叶尖的射流系数，从而达到了控制泄漏流动的目的；选择合适的负荷分布和凹槽几何能够提升刮削涡的堵塞效果并扩大控制范围；均匀加载叶片使用叶尖凹槽时控制泄漏流的效果更加明显；径向间隙的大小直接影响叶顶凹槽内部流动结构的产生和演化，从而改变凹槽叶尖控制叶尖泄漏的效果。
- 叶栅 /
- 机匣运动 /
- 凹槽叶尖 /
- 泄漏流动 /
- PIV
Abstract: The tip leakage flow is an important factor that causes the internal loss of the aeroengine turbine. The squealer tip can effectively control the tip leakage flow. Accurate understanding of the tip leakage flow structures in the cavity contributes to the understanding of the flow characteristics of the leakage flow and the physical mechanism of the leakage loss. In order to study the change of flow structures in the tip cavity when considering the relative casing motion and the effect on the leakage flow, a low-speed turbine cascade testing facility is built that can model the relative casing motion. The test facility can study factors such as blade profiles, different tip structures, and different incidence angles. A visual testing method of Particle Image Velocimetry (PIV) is proposed to obtain the complex flow structures within the tip cavity. The measurement method developed can obtain the complex flow field and successfully capture the scraping vortex in the tip cavity. In addition, the evolution of the flow structures in the tip cavity is analyzed with the help of numerical results under different casing motion conditions. An aero-labyrinth like sealing effect is formed by the scraping vortex. This sealing effect reduces the equivalent flow area at the gap outlet and diminishes the discharge coefficient of the squealer tip, therefore finally achieving the purpose of controlling the leakage flow. Choosing the appropriate blade load distribution and cavity geometry can improve the clogging effect and expand the control range of the scraping vortex. Mid-loaded blades have a more obvious effect on controlling the leakage flow when using the cavity tip. The tip gap height affects the generation and evolution of the flow structure in the tip cavity by which changes the effect of controlling the leakage flow.
- cascade /
- casing motion /
- squealer tip /
- leakage flow /
- PIV

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图 1 实验设施整体布局^[20]

Fig. 1 Structural sketch of wind tunnel and testing facility^[20]

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图 2 收缩曲线示意图

Fig. 2 Schematic of the contraction

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图 3 风洞出口速度场分布

Fig. 3 Wind tunnel exit velocity field distribution

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图 4 叶栅实验台

Fig. 4 Cascade test platform

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图 5 调节挡板

Fig. 5 Adjustable plate

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图 6 不同攻角状态示意图

Fig. 6 Sketch of bottom plate at different incidence angles

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图 7 端壁运动机构

Fig. 7 Moving casing simulator

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图 8 实验段

Fig. 8 Testing facility

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图 9 涡轮叶栅

Fig. 9 Turbine cascade

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图 10 两种叶型与原叶型对比

Fig. 10 Comparison of two blades with original blade

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图 11 叶栅出口周期性验证^[21]

Fig. 11 Periodic verification of cascade outlet^[21]

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图 12 测量方法示意图

Fig. 12 Sketch of PIV test method

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图 13 测量截面沿流向的分布

Fig. 13 Distribution of test section along the flow direction

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图 14 拍摄视场

Fig. 14 View field

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图 15 计算网格示意图

Fig. 15 Schematic of computing grid

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图 16 网格无关性验证

Fig. 16 Grid independence verification

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图 17 叶顶测压孔分布

Fig. 17 Distribution of pressure hole

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图 18 叶顶静压分布对比

Fig. 18 Comparison of blade tip static pressure distribution

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图 19 间隙出口泄漏量沿流向分布

Fig. 19 Leakage flow rate distribution along the streamwise direction at the gap outlet

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图 20 射流系数沿流向分布

Fig. 20 Distribution of discharge coefficient along the streamwise direction

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图 21 间隙出口有效流通面积沿流向分布

Fig. 21 Distribution of equivalent flow area along the streamwise direction

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图 22 凹槽叶尖主要流动结构

Fig. 22 Vortices in the tip region

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图 23 不同截面的流动结构(实验结果)

Fig. 23 Flow structure at different test sections (experimental results)

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图 24 凹槽腔内流线分布(数值结果)

Fig. 24 Distribution of streamlines in the cavity (numerical results)

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图 25 各截面泄漏流速度矢量图(数值结果)

Fig. 25 Velocity vector of leakage flow at different sections (numerical results)

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图 26 凹槽尾缘截面泄漏流速度矢量图(数值结果)

Fig. 26 Velocity vector of leakage flow near the cavity end (numerical results)

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图 27 叶片负荷分布

Fig. 27 Blade load distribution

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图 28 后加载叶片间隙出口泄漏量沿流向分布

Fig. 28 Leakage flow rate distribution along the streamwise direction at the gap outlet of after-loaded blade

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图 29 后加载叶片射流系数沿流向分布

Fig. 29 Distribution of discharge coefficient along the streamwise direction of after-loaded blade

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图 30 后加载叶片间隙出口有效流通面积沿流向分布

Fig. 30 Distribution of equivalent flow area along the streamwise direction of after-loaded blade

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图 31 后加载叶片不同截面流动结构(实验结果)

Fig. 31 After-loaded blade Flow structure (experimental results)

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图 32 均匀加载叶片间隙出口泄漏量沿流向分布

Fig. 32 Leakage flow rate distribution along the streamwise direction at the gap outlet of mid-loaded blade

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图 33 均匀加载叶片射流系数沿流向分布

Fig. 33 Distribution of discharge coefficient along the streamwise direction of mid-loaded blade

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图 34 均匀加载叶片间隙出口有效流通面积沿流向分布

Fig. 34 Distribution of equivalent flow area along the streamwise direction of mid-loaded blade

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图 35 均匀加载叶片不同截面流动结构(实验结果)

Fig. 35 Mid-loaded blade flow structure (experimental results)

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图 36 不同加载叶片周向平均总压损失系数分布

Fig. 36 Distributions of the pitch-wise averaged total pressure loss coefficient of different loaded blades

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图 37 不同加载叶片累计泄漏量

Fig. 37 Accumulated leakage flow rate of different loaded blades

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图 38 不同加载叶片平均总压损失系数

Fig. 38 Total pressure loss coefficient of different loaded blades

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图 39 不同加载叶片累计泄漏量差值

Fig. 39 Difference of cumulative leakage flow rate of different loaded blades

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图 40 2 mm间隙不同截面流动结构(实验结果)

Fig. 40 Flow structure of 2 mm gap (experimental results)

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图 41 4 mm间隙不同截面流动结构(实验结果)

Fig. 41 Flow structure of 4 mm gap (experimental results)

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图 42 不同间隙平均总压损失系数

Fig. 42 Total pressure loss coefficient of different gaps

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图 43 不同间隙累计泄漏量差值

Fig. 43 Difference of cumulative leakage flow rate of different gaps

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表 1 叶片几何参数

Table 1 Blade geometries

Geometry parameter	Value
Blade chord	109.8 mm
Axial blade chord	77.8 mm
Blade pitch	85.5 mm
Blade height	180 mm
Number of blades	7
Gap height	2~4 mm

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表 2 计算域网格信息

Table 2 Computing domain grid information

	Number of nodes in the gap	Total number of elements/10⁶
Grid1	21	2.37
Grid2	29	2.63
Grid3	37	2.90
Grid4	45	3.16
Grid5	53	3.43

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